TDI diesel engine. The most reliable Volkswagen diesel engines according to owner reviews

05.08.2023

Used only on commercial vehicles. Such engines in passenger cars are a real curiosity for Russian car enthusiasts. Previously, foreign manufacturers (including VAG) did not officially supply such engines to the domestic market. But now cars and crossovers from Volkswagen with a TDI engine have begun to appear. What it is? Let's look at it in our article.

Characteristic

First, we note that engines with this abbreviation are found not only on Volkswagens.

Audi also has these units. TDI engines are engines with turbocharged diesel injection (hence the abbreviation). These units are also distinguished by the direct supply of Common Rail fuel.

Peculiarities

The main feature is the turbine that is equipped with the TDI engine. a mechanism that provides forced air supply, thereby increasing torque and power of the motor. But unlike other engines, the 2.0 TDI has a special turbine design - with variable geometry. How is it different from conventional compressors? This design allows you to regulate the magnitude and direction of the exhaust gas flow. This gives a significant increase in power and high fuel efficiency. So, from two liters of volume you can get up to 170 horsepower. And thanks to the direct injection system, fuel consumption is about 5.5 liters in the combined cycle.

Some TDI engines in Volkswagen are equipped with a VNT turbine.

This abbreviation means that it is a compressor with a variable nozzle. The supplier of such turbines for Volkswagen is Garrett. The design of this unit assumes the presence of:

Vacuum drive.
Control mechanism.
Guide vanes.

The latter are designed to change the speed of exhaust gas flow. This occurs by adjusting the channel cross-section. Thus, the blades can rotate around their axis at a certain angle. This action is performed using a control mechanism. It consists of a lever and a ring. The mechanism is activated by a vacuum drive. It is he who acts on the lever through a special rod. The vacuum drive is equipped with a boost pressure limiting valve. It is connected to the electronic engine management system. The mechanism is activated by the boost pressure and intake air temperature.

TDI and Audi TT

The TT is one of the most popular coupes from Audi. Previously, the car was equipped only with gasoline power plants. Diesel units were previously considered “vegetable” and had low traction. In addition, such a sports coupe simply needed a high-speed engine. But after using the TDI engine on the Audi TT, all stereotypes were dispelled.

This diesel engine had simply incredible performance. With a two-liter displacement, it developed 170 horsepower and as much as 350 Nm of torque. This gave a significant increase in dynamics. The car accelerated to hundreds in 7 and a half seconds. And the maximum speed was 226 kilometers per hour. And now the most important point is fuel consumption. And this unit consumed only 5.3 liters per hundred in mixed mode. You won't believe it, but this is real passport data from the manufacturer.

Ecologically pure

The TDI line of engines has held a leading position on the market for 20 years. One of them featured Clean Diesel technology. It provides deep cleaning of exhaust gases by converting nitrogen oxides into water vapor. The system has already been put into practice and has been successfully used in the USA since 2014. The 3.0 TDI engine meets all standards for the content of harmful substances in the exhaust. CO emissions per kilometer are only 130 grams.

What are the advantages of the TDI engine?

We have already found out what it is. Now let's look at the main advantages of these turbocharged units. In general, after Audi joined the VAG concern, the latter took a leading position in the list of diesel engine manufacturers. Thanks to innovative engineering solutions, their engines are distinguished by:

High fuel efficiency.
Low noise level (almost inaudible at idle).
High dynamics and torque.

Also, these power plants meet modern environmental requirements (Euro 6 exhaust standard). A significant increase in power was achieved thanks to the special design of the turbine. Unlike other engines, those from VAG are capable of operating at a pressure of 2 thousand bar.

Modern analogues produce only 1300 Bar. Also in TDI engines the injector is combined with a pump. This allows for maximum control over fuel injection.

Conclusion

So, we found out what features the TDI engine has, what it is and what its advantages are. At the moment, TDI engines are among the most powerful, quiet and environmentally friendly. It is not surprising that they occupy a leading position in the global market.

The abbreviation HDI is assigned to motors that are based on technology Common Rail (developed by Bosch in 1993). The engine itself and HDI technology were developed by the world famous automobile concern PSA Peugeot Citroen. HDI, as I already said, belongs to the line of engines with direct injection, the characteristic differences are reduced fuel consumption by ~15%, reduced noise by ~10 dB, while simultaneously increasing power by as much as ~40%. Motors with the HDI prefix are considered more durable and “tenacious”.

TDI engine

The abbreviation TDI is perhaps the most popular and easiest to decipher. The first letter "T" in this abbreviation denotes the presence of turbocharging, which allows you to get a serious increase in power. It has all the properties inherent in turbocharged engines, it is more economical, has cleaner exhaust, and is more expensive to maintain. In addition, few people know that most turbines installed on turbo engines are designed for ~150-200 thousand km. mileage, and this despite the fact that the engine itself, as a rule, is “millionaire”.

SDI engine

SDI class motors are distinguished by their long life and simplicity of design. Long mileage is not a problem for SDI, the motors are very durable and reliable, but if repairs are still required, the cost is unlikely to please you.

CDI engine

The motor with the CDI nameplate is a Mercedes development, which is based on the same Common Rail technology as the above power units. Engines of the CDI line are more demanding in terms of fuel quality (the fuel system, injectors, etc. often “compost the brains”), while they are very economical and dynamic on the road.

Well, that's all. I hope I clearly explained the difference between HDI, TDI, SDI, and CDI, now you can easily navigate and choose the engine that is suitable for your type and class. Thank you for your attention and see you again on .

The TDI family of engines is a line of diesel power units produced by the German auto giant Volkswagen. Diesel engines, designated by the abbreviation TDI (Turbocharged Direct Injection), are units with a turbocharger and are equipped with a direct fuel injection system. These internal combustion engines can be found on various diesel car models, the manufacturers of which are part of the WAG concern (Audi, Volkswagen, Skoda, etc.)

Read in this article

The history of the TDI engine

The diesel engine has always attracted various companies with its untapped potential. The main task set before the engineers was to transform a noisy, low-speed and low-speed unit into a motor that could be easily installed in passenger cars. The result was the creation of a powerful, economical and environmentally friendly diesel engine, which in its performance characteristics was as close as possible to a gasoline power unit.

The pioneer in this direction was the Audi company, which back in 1980 installed a 1.6-liter diesel 54-horsepower engine under the hood of its popular Audi 80 model. Further improvement and development of technology led to the fact that already in 1989 Audi was the first in the world to establish and launched into mass production a compact, high-torque and powerful turbodiesel engine, which received the designation TDI, widely known today.

The first TDI was a 5-cylinder diesel engine, had a displacement of 2.5 liters, and was equipped with a turbocharger with an intercooler (charge air intercooling system). The maximum power of this engine was 120 hp. The torque indicator was at around 256 Nm and was achieved at 2250 rpm.

Since its appearance on the market, this power unit has become quite popular, as it was a worthy alternative not only to diesel engines from other manufacturers, but was also quite capable of competing with gasoline engines. Audi's TDI provided excellent dynamics, while fuel consumption was significantly lower compared to other analogues.

Features and benefits of the TDI engine

After Audi joined WAG, the Volkswagen concern took first place in the list of diesel engine manufacturers. Innovative engineering solutions and proven production technologies provided TDI engines with:

low noise level during operation;
high torque;
low fuel consumption;
reduction of exhaust gas toxicity;

Today, the TDI diesel engine has a number of advantages compared to its analogues, among which fuel efficiency and efficiency are highlighted. One of the main advantages is deservedly considered to be higher injection pressure compared to the performance of other systems. The injection pressure in TDI engines is at around 2050 bar, while analogues produce only 1350 bar.

In TDI, the injector is combined with a pump, which allows for maximum control over all fuel injection processes. This solution provides the TDI engine with high torque, as well as flexible operation of this diesel engine in different modes. Thanks to this fuel supply system, the combustion process of diesel fuel in TDI engines is more uniform and occurs “delicately,” that is, with minimal shock loads. For this reason, the noise level during diesel operation has significantly decreased, and the content of nitrogen oxide in the exhaust gases has also dropped. In other words, the TDI diesel engine is powerful, quiet, least harmful to the environment and the most economical engine among diesel power units available on the market.

Reliability of diesel TDIs

The installation of turbocharging allowed the diesel engine to develop more power, and the diesel efficiency also increased. As for TDI engines, these engines are quite reliable if used correctly. The health of these internal combustion engines is most strongly influenced by the quality of the fuel and timely maintenance. With proper care, the engine itself can even turn out to be a “millionaire”.

The weak point of TDI is the injectors and turbocharger. The service life of the injectors directly depends on the quality of the diesel fuel and the general condition of the TDI diesel power system. The service life of the turbine can vary, the average resource is 120-160 thousand km.

Fuel injection in TDI engines

In the early stages of the development of diesel internal combustion engines, the pressure in the system, which involves the presence of a fuel injection pump in conjunction with simple mechanical injectors, was only 20-40 bar. A modern diesel engine has a minimum pressure of 1600 Bar and higher. The tendency to increase fuel injection pressure is due to the fact that diesel engines have a very short time allotted for the mixture formation process.

If the crankshaft rotates at 2000 rpm, then only 3-4 milliseconds are allocated to mix a portion of diesel fuel with air. Increasing the crankshaft speed further shortens this time period. Also, the preparation of a homogeneous fuel-air mixture becomes possible only by increasing the injection pressure. In the case of low pressure, the fuel mixture will be of poor quality, and the combustion process will be low efficient. The result is increased toxicity of diesel exhaust and low efficiency.

Previously, the fuel injection pump on diesel engines was responsible for fuel injection, which works in tandem with mechanical injectors; today, common rail systems are installed on diesel engines. Since the combustion process in a diesel engine is an explosion from the contact of a portion of diesel fuel with air heated during the compression stroke, the injection time is very limited.

The fuel injection pump in a modern diesel engine simply creates pressure in the common line, and TDI piezo injectors (piezoelectric injectors) are capable of injecting a clearly defined amount of diesel fuel into the cylinders of a diesel engine in a very short period of time (less than 0.2 milliseconds) at the command of the ECU.

Also in some designs of diesel internal combustion engine power systems you can find so-called pump injectors. This means that each injection nozzle is equipped with its own high pressure pump. It turns out that the development of diesel technology today comes down to increasing injection pressure and maximum efficiency of the turbocharging system. This way it is possible to solve the main problems: increase power and reduce the level of exhaust gas toxicity.

TDI turbocharging: variable geometry turbine

Not only dynamics, but also efficiency and environmental friendliness largely depend on the efficiency of the TDI turbocharger. Correct air pressure must be realized over as wide a range as possible. For this reason, TDI engines are equipped with a turbocharger with variable turbine geometry.

The leading turbine manufacturers in the world use the following names:

VGT turbine (from the English Variable Geometry Turbocharger, which means turbocharger with variable geometry). Produced by BorgWarner.
Turbocharger for diesel VNT (from the English Variable Nozzle Turbine, which means a turbine with a variable nozzle). This name is used by Garrett.

A variable geometry turbocharger differs from a conventional turbine in that it has the ability to adjust both the direction and magnitude of the exhaust gas flow. This feature allows you to achieve the most suitable turbine speed in relation to a specific operating mode of the internal combustion engine. In this case, the compressor performance increases greatly.

For example, the VNT turbine is based on special guide vanes. Additionally, there is a control mechanism, and the presence of a vacuum drive is also noted. These turbine blades rotate at the required angle around their axis, thereby being able to change the speed and direction of the exhaust flow. This occurs due to a change in the cross-sectional area of the channel.

The control mechanism is responsible for rotating the blades. Structurally, the mechanism has a ring and a lever. The lever is influenced by a vacuum drive, which controls the operation of the mechanism through a special rod. The vacuum drive is controlled by a separate valve that limits the boost pressure. The valve is an integral element of the electronic engine control system and is activated depending on the boost pressure. This value is measured by separate sensors:

a temperature sensor that measures the intake air temperature;
boost pressure sensor;

In other words, the turbocharging on the TDI works so that the charge air pressure is always optimal at different engine speeds. In fact, the turbine doses the energy of the exhaust gas flow.

As is known, at low engine speeds the exhaust flow rate (energy) is quite low. In this mode, the guide vanes are usually closed, thereby achieving a minimum cross-section in the channel. As a result of passing through such a channel, even a small amount of gases spins the turbine more efficiently, causing the compressor wheel to rotate noticeably faster. It turns out that the turbocharger provides greater performance at low speeds.
If the driver sharply presses the gas, then the effect of the so-called “turbo lag” occurs in a conventional turbine. Turbo lag should be understood as a delayed response to pressing the gas pedal, that is, not an immediate increase in power, but a pick-up after a short pause. This feature is due to the inertia of the turbocharging system, as a result of which the gas flow is insufficient at the moment of a sharp increase in crankshaft speed. In turbines with variable geometry, the guide vanes rotate with a certain delay, which allows you to maintain the required boost pressure and practically get rid of turbo lag.
When driving at high and close to maximum engine speeds, the exhaust gases have maximum energy. To prevent the creation of excess boost pressure, the blades in variable geometry turbines are rotated so that a powerful flow of gases moves through a wide channel with the largest cross section.

We also recommend reading the article about the service life of diesel turbines. From this article you will learn about the service life of this unit in comparison with gasoline analogues, and will also get the opportunity to familiarize yourself with the basic tips and recommendations for increasing the service life of a diesel engine turbine.

The relatively short service life of the turbocharger is due to the fact that only variable geometry turbines are installed on the TDI. During engine operation, the turbocharger spins up to 200 thousand rpm and constantly interacts with the flow of exhaust gases heated to 1000 degrees Celsius. Such thermal and mechanical loads, as well as the individual design features of these turbines, relatively quickly lead to the need to repair or replace the turbocharger.

Let's sum it up

Thanks to the developments and engineering solutions of Audi, the diesel engine managed to rise to a new stage in its evolution. The efficiency of TDI engines is a kind of record. The Audi 100 TDI covered 4,814.4 kilometers on just one full tank of fuel. The average speed was about 60 km/h, while the average fuel consumption was just over 1.7 liters per 100 km. Also, TDI engines closely compete with gasoline units not only on the streets, but also on race tracks. An excellent example is the diesel Audi R10 TDI, which regularly wins victories on the most difficult tracks.

Finally, we would like to add that the main guarantee of a long life for both a TDI engine and any other is the correct selection and timely replacement of engine oil, proper operation and driving on high-quality fuel, as well as professional service. Compliance with these conditions will allow the engine and other related systems to remain operational for hundreds of thousands of kilometers.

Which is better HDI, TDI, SDI, or CDI? What do these abbreviations stand for, and what is the difference between these engines?

It is no secret that diesel engines are more profitable than gasoline engines, but deciding on the type of fuel does not mean deciding on the type of diesel engine itself. A fairly common problem for many beginners is confusion between numerous abbreviations (HDI, TDI, SDI, CDI), on which a lot depends in the future.

It depends on the “character” of the car, its “susceptibility” to breakdowns, as well as the cost of repairing these breakdowns, as well as fuel consumption and much more. In this article, I will try to explain as clearly as possible what the differences are between different modifications of diesel engines, so that you can get your bearings and choose the most suitable option for yourself.

Looking ahead, I will say that the last two letters “.DI” of all the above abbreviations mean Direct Injection - direct injection. Direct injection technology, or as it is also called, is one of the most advanced today and provides for the presence of a common channel through which fuel is supplied.

HDI engine

TDI engine

The abbreviation TDI is perhaps the most popular and easiest to decipher. The first letter “T” in this abbreviation denotes the presence of turbocharging, which allows you to get a serious increase in power. A turbo engine has all the properties inherent in turbocharged engines; it is more economical, has cleaner exhaust, and is more expensive to maintain. In addition, few people know that most turbines installed on turbo engines are designed for ~150-200 thousand km. mileage, and this despite the fact that the engine itself, as a rule, is “millionaire”.

Current: How to check a diesel engine turbine? Diagnosing faults at home

SDI engine

CDI engine

The motor with the CDI nameplate is a Mercedes development, which is based on the same Common Rail technology as the above power units. Engines of the CDI line are more demanding in terms of fuel quality (often the fuel pump, injectors, etc. “compost the brains”), while they are very economical and dynamic on the road.

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TDI (Turbocharged Direct Injection) engine: what is it?

The TDI diesel engine (the abbreviation stands for Turbocharged Direct Injection) is the brainchild of engineers from the Volkswagen automobile concern, work on which began in the 70s of the twentieth century. The name TDI itself is a trademark protected by a patent, to which the concern has exclusive rights, which means that the origin of the engine can be unmistakably determined by such an inscription.

Similar power units are installed on the entire subsidiary range of the German automobile giant, be it cars, trucks, jeeps, minibuses. Also, some models of companies with which Volkswagen has collaborated for some time have TDI engines. Let's take a closer look at what a TDI engine is? What are its advantages and is it reliable and promising?

Overall assessment of the benefits of TDI

Among the identified advantages of the Turbocharged Direct Injection power plant, one cannot help but pay attention to the following:

power;
efficiency;
compactness;
environmental friendliness.

This set was not determined immediately and not even after the appearance on the market in 1980 of the Audi 80 with a TDI under the hood, but only after numerous modifications and improvements, which led to the launch in 1989 of a new powerful turbodiesel, which in many ways is not inferior to gasoline units.

Experts recognize that TDI is one of the best modern diesel engines, the efficiency of which is determined based on the ratio of initial power and torque per unit of cylinder volume and fuel consumed.

The role of the variable geometry turbine

The main advantage of the engine, along with the direct injection system, is variable geometry turbocharging, which makes this type of engine competitive not only in related circles, but also in gasoline ones. In such a turbocharger, the direction and parameters of the exhaust gas flow can be adjusted, thanks to which it is possible to achieve the most suitable turbine rotation speed, and this has a very positive effect on performance. A conventional turbine does not provide such a possibility.

The VNT turbine, for example, is equipped with guide vanes, a vacuum drive and a control system. Moving around their own axis, the blades occupy a position at the desired angle, thus changing the cross-section of the channel. This allows you to adjust the speed and vector of the exhaust.

The rotation of the blades is controlled by a control mechanism equipped with a ring and a lever that receives the influence of a vacuum drive, regulated by a separate rod. In turn, the drive is controlled by a valve that is part of the engine ECU and responds to changes in boost pressure thanks to signals from the temperature sensor (at the intake) and the boost pressure sensor.

In general, a TDI turbine is a kind of exhaust flow energy dispenser that provides the required air pressure in any engine operating mode.

Read also: What is a TSI engine, its design, pros and cons.

Technological differences TDI

TDI is economical in fuel consumption and shows respectable efficiency. It is worth noting the high efficiency of the installation due to the increased injection pressure, reaching 2050 bar, and this despite the fact that analogue models show only 1350 bar. As is known, the injection pump is responsible for maintaining the total pressure in the line, and piezoelectric injectors, based on a signal from the electronic control unit, carry out strictly dosed injection, spending less than 0.2 ms.

A significant step towards increasing the efficiency of diesel engines was the introduction of the Common rail system (battery supply system), thanks to which the dependence of the injection mechanism on the crankshaft angle and engine operating mode is removed. This creates the conditions for fuel injection into the cylinder under high pressure when operating under light loads. Although the Common rail system is superior in maintainability to the conventional fuel supply system, its presence forces special requirements on fuel quality, in which it is somewhat inferior to the traditional system.

Among the atypical features of TDI engines are three points:

By combining the injector with the pump, it was possible to provide comprehensive control of the fuel injection mechanism, which increased torque and functional elasticity when changing operating conditions.
Fuel combustion is not accompanied by high shock loads, so the engine noise is low.
The concentration of nitrogen oxide in the exhaust is low, which explains the acceptable toxicity level, which remains a problem for other types of engines. This power unit is rightfully recognized as the most environmentally friendly among its peers.

TDI engine problems

According to specialized resources, the TDI reliability indicator is quite high and with properly organized maintenance it will withstand a million kilometers. The most modern compressors have also increased in reliability and sometimes “live” no less than the engine itself. However, on average, the service life of most turbines is limited to 150-200 thousand kilometers. This pattern is explained by the high temperature of the exhaust gases, reaching 1000℃, and the significant rotation speed, close to 200 thousand rpm.

Another vulnerability is the injectors, the service life of which is directly dependent on the quality of the fuel and the health of the power system.

To extend the life of TDI's weakest links, there are some important steps to keep in mind:

timely oil change;
timely replacement of the air filter;
regular diagnostics of boost pressure.

It remains to add that since Turbocharged Direct Injection engines are quite complex for self-service, the right solution would be to turn to the services of specialized services.

general analysis, pros and cons of the motor

The abbreviated name for the TDI diesel engine stands for Turbocharged Direct Injection. The creation of Volkswagen design engineers at the automobile concern.

The development of this engine began in the distant 70s. The concern has exclusive rights to the name TDI, since the name is protected by a patent, so it is always possible to determine the origin of such engines without errors.

The entire subsidiary range of cars of German origin is equipped with such power units, regardless of the type of vehicle, which includes minibuses, trucks, cars and jeeps.

Some other companies with which Volkswagen has signed a cooperation agreement also have the right to use TDI engines. To understand, it is necessary to characterize this power unit.

General analysis of TDI engines

The main characterizing advantages of such engines that you need to pay attention to are:

– environmental friendliness;

– efficiency;

– compactness;

– power.

All these positive characteristics did not appear immediately. Even after the market launch of the Audi 80 with TDI engine, such engine characteristics were not observed to prevail. Only after painstaking work and various types of modifications in 1989, manufacturers released a powerful turbodiesel, which was absolutely not inferior to gasoline engines.

Experts confirm that TDI engines are the best in modern times. Their effectiveness is determined from the proportion of the initial power and torque per 1 cylinder volume and consumed fuel.

Variable geometry turbine functions

Along with the direct injection system, the main indisputable advantage of the engine is variable geometry turbocharging, which makes such engines competitive not only among diesel, but also gasoline engines.

In this turbocharger, the distribution and performance of the exhaust gas flow are subject to regulation. Due to this, it is possible to achieve the desired turbine rotation speed, which has a positive effect on productivity. A simple turbine does not have this capability.

If we consider the VNT turbine, its design includes guide vanes, a control system and a vacuum drive. When moving around their axis, the blades are in the position of the desired angle, and due to this, the cross-section of the channel changes. Based on this, it becomes possible to adjust the speed and vector of the exhaust.

The control mechanism always keeps the rotation of the blades under control. It is equipped with a ring and a lever that receives the influence of a vacuum drive controlled by an independent draft.

The valve is a drive control; it is part of the engine ECU and is responsible for changing the boost pressure using signals that come from the temperature sensor and the boost pressure sensor.

The exhaust flow energy dispenser is a kind of turbine on a TDI engine. The dispenser provides the necessary air pressure under any engine operating conditions.

TDI technical differences

The AUDI v12 shows respectable efficiency and economical fuel consumption. Due to the increased injection pressure, which reaches 2050 bar, the installation is highly efficient. When compared with other models, their performance does not exceed 1350 bar.

Everyone knows that the injection pump is responsible for maintaining the overall pressure in the line. Based on a signal from the electronic control unit, piezoelectric injectors produce dosed injection at a time cost of less than 0.2 ms.

The common rail battery supply system has provided a way to improve the efficiency of diesel engines. Thanks to which the injection mechanism becomes independent of the crankshaft rotation angle and the operating mode of the engine.

Under increased pressure when working with light loads, the prerequisites are created for fuel injection into the cylinder. Compared to a simple fuel supply system, the Common rail system is superior in maintainability. Its presence requires increased demands on the quality of fuel, in which a simple system loses.

Based on the number of atypical features of TDI engines, several points can be corrected:

Integrated control of the fuel injection device originated from the connection of the injector with the pump. Due to this, when modifying the operating mode, the torque increased.

There are no high shock loads during fuel combustion, this is due to the low noise level of the engine.

The concentration of nitrogen oxide in the exhaust is low. In this regard, the toxicity indicator is acceptable, which cannot be said about other types of engines. Among its peers, this unit is rightfully considered the most environmentally friendly.

TDI engine malfunctions

The reliability indicator of TDI engines is quite high, according to data from specialized resources. With proper, well-organized maintenance, it can be used for millions of kilometers.

The degree of reliability of modern compressors has also increased and sometimes reaches no less than the service life of the engine itself. 150-200 thousand kilometers is the average resource of most turbines.

This resource is achieved due to the high temperature of the exhaust gases, which can reach 1000 degrees, as well as the high rotation speed, which approaches two hundred thousand revolutions per minute.

The service life of the injectors directly depends on the serviceability of the power supply system and the quality of the fuel, which is a disadvantage.

The most significant measures that will extend the life of TDI's weak links are:

– timely oil change;

– periodic change of the air filter;

– systematic diagnosis of boost pressure.

Turbocharged Direct Injection engines are quite difficult to maintain independently, so it is always recommended to contact specialized car services.

Summarizing

The diesel engine managed to rise to a completely new level, thanks to the developments and solutions of engineers. A record was set for the efficiency of TDI engines. On the first full tank of fuel, the Audi 100 TDI model covered a mileage of 4814.4 kilometers

Average fuel consumption was 1.7 liters per 100 km, and the average speed was 60 km/h. TDI engines take the lead over gasoline engines not only in the city, but also in racing competitions. The diesel Audi R10 TDI regularly achieves victories, even on the most difficult tracks.

With an error-free selection and timely replacement of engine oil, with proper operation and, of course, using specialized service, the TDI engine will live a long, carefree life. Subject to the simplest measures and conditions, these motors will remain operational for many thousands of kilometers.

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Features of the TDI engine in Volkswagen cars

The TDI engine offers increased power with low emissions.
The abbreviation TDI (Turbo Diesel Injection) refers to a diesel power unit that has increased torque, low fuel costs and high power. What other positive aspects and specific features does such a motor have?

The only Volkswagen model that comes with a TDI is the Toaureg all-wheel drive SUV. This type of engine is not the most popular in Volkswagen cars, unlike the TSI. Nowadays (2016) only TSI engines are installed on Passat B8, Passat CC, Tiguan. In addition to TSI, Golf and Jetta also have MPI engines.

Every modern engine with a turbocharger and direct injection in Volkswagen vehicles is labeled TDI. An important distinguishing feature for each such engine is that fuel injection, which is carried out under increased pressure along with variable turbine geometry, allows combustion to be carried out extremely efficiently.

When using direct fuel injection technology, an efficiency level of a maximum of 45 percent can be achieved. As a result, a significant portion of the possible fuel energy is converted into kinetic energy, that is, into motor power. Although this requires that the fuel burns almost completely and efficiently. This is achieved using a special configuration of the combustion chamber.

The main positive aspects of TDI

The TDI engine system is economical. Its most important positive aspects are:

low fuel consumption;
small volume of emissions of harmful substances;
the need to carry out auto service work and maintenance only occasionally.

Directly at low speeds, it is possible to significantly increase power up to the maximum rotational speed. There is an improvement in acceleration performance, and at the same time the quality of operating dynamics. The increased torque also ensures maximum driving comfort when equipped with a TDI engine.

Direct or pilot fuel injection?

Direct fuel injection engines burn fairly harshly. As a result, during a cool start, a distinctive hum usually appears. To avoid this, diesel fuel is pre-injected.

Before the main cycle, a small amount of fuel is supplied directly into the combustion chamber. The pressure in the chamber does not increase immediately, but gradually, so combustion becomes “soft”.

Reducing harmful emissions

After the fuel is pre-injected, a post-injection process occurs, resulting in a reduction in the emission of harmful substances. Nitrogen oxides in the exhaust are minimized due to the fact that a little fuel enters the combustion chamber based on the speed. When the air that is absorbed and at the same time the exhaust gases are mixed, the temperature in the chamber decreases, so the volume of nitrogen oxides decreases.

Engine turbocharger

TDI engines use a turbocharger with variable geometry, which allows the air that is absorbed to be compressed. Due to this, the volume of absorbed air in the chamber increases. As a result, engine power increases at the same volume and at the same speed.

Two turbines form the turbocharger device. The turbine located in the exhaust tract begins to rotate from the outgoing mass of exhaust gases. It begins to move the compressor wheel, which compresses the air directly at the inlet. The air heated during compression is cooled and then enters the chamber. Since when the temperature decreases, the volume of air also decreases, there is more of it in the chamber.

Changing turbine geometry

The VTG system is now quite successfully used in TDI engines. At low speeds and low gas volume, the control unit changes the location of the mechanical propelling blades, at which the diameter narrows. This accelerates the gas flow and increases pressure. As the engine speed increases, the exhaust pressure increases, so the control unit, on the contrary, increases the pipeline diameter. Such superchargers help provide additional power to the engine, reducing emissions and increasing throttle response.

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What is a TDI engine

Many countries are experiencing rapid growth in the popularity of diesel engines. That’s why motorists are actively interested in the most optimal options among cars that have internal combustion engines running on diesel fuel under the hood.

The TDI family of engines is deservedly considered one of the best diesel engines. This is a development by Volkswagen, which equips a wide range of models of its cars and cars that are part of WAG with such engines. This includes cars from Audi, Volkswagen, Skoda, etc. Although it would be fair to call the Audi developers the authors of the project. But since they are part of a single group, this is not of fundamental importance.

Although work on TDI began in the 70s of the last century, it was only in the 21st century that these installations became truly complete, operational and highly efficient. Many people want to buy a car with such an engine. And there are a number of objective reasons for this.

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But before making a final decision, it is recommended to study in detail all the features of these engines, consider their technical aspects, and take into account their strengths and weaknesses.

A little history

Diesel engines have always been considered as internal combustion engines with rather poorly realized potential. This attracted the attention of a large number of automakers.

The engineers' task was to make the engine less noisy, slower and higher-speed, which would make it possible to install similar internal combustion engines on passenger car models. All efforts and hard work were ultimately crowned with success, and the world saw a powerful, economical and very environmentally friendly diesel power unit, the performance characteristics of which were practically not inferior to its gasoline counterpart.

The pioneer is Audi, which in the 80s produced and installed on the Audi 80 a naturally-aspirated diesel engine with a displacement of 1.6 liters and a power of 54 horsepower. As technology developed and improved, already in 1989 it was possible to establish mass assembly of compact, but at the same time powerful and high-torque turbodiesels, which received the world famous name TDI.

The very first TDI was presented in the form of a 2.5-liter 5-cylinder engine with an intercooler and turbocharging. All this made it possible to achieve a power of 120 horsepower with a torque of 256 Nm.

The launch of this engine on the market showed that there is great demand for it. TDI has become an excellent alternative to gasoline units and has managed to impose competition. TDI differed favorably from other diesel engines with excellent dynamics and low fuel consumption.

Features and Benefits

First of all, car enthusiasts are interested in what a TDI engine is and what the abbreviation used stands for. In fact, it is not difficult to understand what TDI means and what the essence of this engine is, if you look at the full name. The full transcript sounds like Turbocharged Direct Injection.

Such engines can be found not only among the WAG model range. There are a number of cars where the engine is a TDI engine. These are products of companies with which Volkswagen cooperates.

It is important to note that the TDI acronym itself is a proprietary trademark. WAG has exclusive rights to it. This allows you to buy a car without any fear and be sure that the engine belongs to WAG.

When Audi became part of WAG, the Volkswagen automaker very quickly became a leader among the best manufacturers of diesel power plants. The innovative solutions and new technologies used have made it possible to obtain a huge list of advantages and privileges. At the same time, the main advantages of TDI turbodiesels are:

slight noise during operation;
excellent torque performance;
low consumption;
low level of toxicity of emitted exhaust.

Although TDI diesel engines offer significant advantages over their competitors, the most significant are their excellent efficiency and economy. These two factors predetermined the success of the project.

Similar characteristics were largely achieved due to higher injection pressure. If we compare it with analogues in which this indicator is at the level of 1350 bar and no higher, then TDI produces 2050 bar.

The engine uses a system in which the injector is combined with a fuel pump. This allows you to control all fuel injection processes. This innovation made it possible to achieve high torque levels with simultaneous smooth operation in different modes.

A special fuel supply system ensures uniform and gentle combustion of fuel, thereby reducing shock loads to a minimum. This has already led to another advantage in the form of quiet operation and reduced exhaust gas emissions.

An important step to improve the efficiency of diesel engines was the introduction of a battery supply system, that is, Common Rail. With its help, it was possible to get rid of the dependence of the injection mechanism on the current angle of rotation of the crankshaft and the operating mode of the engine. This created the conditions for fuel injection into the working cylinders under high pressure even when the engine was operating at minimal load.

Despite the fact that the battery fuel supply system is not inferior to traditional systems in terms of maintainability, and in some places surpasses it, it is extremely important to use the highest quality fuel. That is, it is better to refuel TDI at proven gas stations.

We can highlight several technological features of these engines that set them apart from their competitors and allow us to talk about some unique, non-standard or atypical solutions.

Since the injector is combined with a fuel pump, the system allows comprehensive control of the fuel injection mechanism. As a result, this led to an increase in torque, smoothness and elasticity of movement, regardless of the current operating mode of the engine.
When diesel combustion occurs in the engine, it is not accompanied by serious shock loads, which occurs on many analogues. This makes it possible to ensure a low noise level during the operation of the power unit.
TDIs are characterized by a very low concentration of nitrogen oxide in the exhaust produced. This explains the fairly adequate level of toxicity, which many other diesel engines cannot achieve. Among its competitors, it is the TDI that is deservedly and rightly considered the most environmentally friendly.

Such features bring the engine to a leading position. This is a very popular motor on the market, which largely justifies its cost.

For the price, this is not the most affordable diesel engine. Therefore, the cost factor sometimes scares away potential buyers. To make sure that your choice is fair and correct, you should further study the motor and be sure to become familiar with its potential faults.

To sum it up, TDI can rightly be called powerful, silent, environmentally friendly engines that minimally pollute the environment. It is not surprising that in Europe there is an increased demand for cars equipped with such engines.

Reliability factor

The fact that we are talking about a turbocharged diesel power unit makes some car enthusiasts doubt the reliability of these engines. Allegedly, due to the turbine, the durability and service life of the unit are significantly reduced.

But in reality everything is somewhat different. It is thanks to the turbocharging system that TDI engines have excellent power performance with a small displacement. This also entailed a noticeable increase in efficiency.

The diesel engines under consideration can rightly be called reliable. Everything directly depends on the specific operating conditions and directly on the car owner’s attitude towards his vehicle.

For engine reliability to really fail, you need to regularly refuel the car at cheap gas stations, where diesel fuel is only price and name. That is, it is the quality of diesel fuel that most strongly influences the performance and serviceability of TDI.

If the motorist chooses good gas stations, fills with proven and high-quality fuel, and also follows standard instructions for timely maintenance, which must be done with absolutely any engine, then in certain cases the viability of the TDI can reach 1 million kilometers. Moreover, these are not fantasies or indicators under absolutely ideal conditions.

To ensure that TDI does not fail, and the car owner can always count on the performance and reliability of his turbodiesel, it is enough to know the 3 main weak points of the engine:

low quality fuel;
fuel injectors;
turbocharger.

We figured out the quality of diesel fuel. Everything here is simple and obvious. Fill with good fuel and there will be minimal problems.

As for such a weak point as injectors, their performance and life cycle are most directly related to the first point, that is, to the quality of the fuel. If you fill in decent diesel fuel and maintain the fuel system in good general condition, the injectors can last a long time and reliably. If necessary, they can be changed. The procedure is not the most complicated and not particularly expensive if the car owner decides to seek help from a car service center.

Of particular note is the turbine, or turbocharger, used on the TDI to improve power, performance and efficiency. The turbine is always the weak point on any engine with a turbocharger, since its resource is noticeably less than the resource of the engine itself.

Practice shows that on average a TDI turbine can faithfully last from 120 to 160 thousand kilometers. Then replacement is required.

Considering the rate of turbocharger wear on many TDI competitor engines, the WAG design has a very respectable performance record. This resource looks quite acceptable and long-lasting for a turbo engine.

It is important to understand one more point here. The development of engines and machines is now carried out in such a way that manufacturers do not expect operation for 15-20 years. In Europe and the USA, it is customary to replace cars after 3-8 years, since they gradually exhaust their service life, environmental performance deteriorates, etc. In our country, even 10-15 years of operation is considered the norm.

The same Europeans are not particularly concerned that the turbine resource is 160 thousand kilometers. When this mileage is reached, the car is scrapped or sold abroad. Having bought such a car and changed the turbocharger, you can safely drive it for at least another 100-120 thousand kilometers.

Already understanding what TDI means and what the letters in this abbreviation stand for, it would be a good idea to take a closer look at the technical aspects of these turbodiesels. And then you can decide for yourself whether it is worth buying cars with engines under the hood designated TDI.

Fuel injection system

When diesel engines were in the earliest stages of their development, the joint operation of the fuel pump (fuel injection pump) and mechanical injectors made it possible to achieve a pressure of no more than 40 bar.

If you take a modern diesel engine, it is capable of delivering 1600 bar and even higher. This trend of pressure growth is explained by the fact that very little time is given for mixture formation in diesel engines.

When the crankshaft rotates at a speed of about 2 thousand revolutions per minute, it takes literally a few milliseconds to create a mixture of diesel fuel and air. The higher the shaft rotation speed, the shorter this time period.

To create a homogeneous and high-quality mixture, high pressure is required. If the pressure is low, the mixture is of poor quality and does not burn completely, which reduces efficiency and increases exhaust toxicity.

In old diesel engines, the unit responsible for pressure was the fuel injection pump, working in tandem with mechanical injectors. Modern diesel engines are equipped with a special system called Common Rail.

If the injection pump can simply create pressure in the line, then the piezoelectric injectors in the TDI system can supply (inject) a strictly defined volume of fuel into the cylinders in an extremely short period of time. The injection time and formation of the air-fuel mixture takes literally 0.2 milliseconds or even less. The corresponding commands are sent through the control unit.

In fact, the whole essence of the development of diesel engine technology is directly related to increasing fuel injection pressure and increasing the efficiency of the turbocharger.

Turbocharging system in TDI

In order for the turbo to operate as efficiently and correctly as possible, a wide range of operation is required. This is why the TDI uses a variable turbine geometry system.

Compared to a conventional turbine, the variable geometry design allows you to adjust the direction and magnitude of the exhaust gas flow. This feature contributes to a noticeable increase in turbine speed depending on the specific operating mode of the engine. The turbocharger thus receives increased performance.

That is, the TDI implements the principle according to which optimal pressure is always created in the engine at all modes and engine speeds. With the help of a supercharger, it is actually possible to dose the energy of the exhaust gas flow.

Here it is worth highlighting several nuances that largely explain the advantages of the turbocharging system in TDI engines.

When the engine is running at low speed, the exhaust flow rate is also low. While in this mode, the turbine guide vanes are often closed, which allows for the creation of a maximum small cross-section in the channel. When a small volume of gas passes through such a channel, it is able to effectively spin the turbine and stimulate the compressor wheel to rotate faster. So it turns out that at low speeds the performance of the turbocharger still remains high.
When you sharply press the gas pedal, a gap appears in a conventional turbine, which is called a turbo lag. That is, the engine’s response to the pressed accelerator pedal is delayed, and the increase in power does not occur instantly, but with a pause. This is explained by the fact that the turbocharging is inertial, and the available gas flow is not enough when the crankshaft speed increases sharply. But because the TDI uses a variable geometry turbine, the guide vanes rotate with some delay. This makes it possible to maintain high boost pressure. This actually prevents the motor from stalling. The effect of turbo lag is almost irrelevant for TDI.
When driving at high and maximum speeds, the exhaust gas has maximum energy. To prevent excessive turbocharging pressure, the blades rotate in a certain way. Thus, a large and powerful gas flow follows a wide channel with a large cross-section.

TDI has a relatively short turbine life. But there is a logical explanation for this. A turbine with variable geometry is used here. Therefore, during operation, the compressor rotates at a speed of up to 200 thousand revolutions per minute, in parallel interacting with air flows from the exhaust, the temperature of which can reach 1000 degrees Celsius.

It is these mechanical and thermal loads, as well as some design features of the TDI, that lead to wear. As a result, repair or complete replacement of a worn turbocharger is required.

How to avoid malfunctions

If you plan to operate a car equipped with a TDI engine for more than 5 years from the date of its release, then you will not be able to prevent wear and tear on the turbocharger even if you really want to. The system has its own resource, which is limited to a maximum of 200 thousand kilometers. When the mileage exceeds this value, the compressor will have to be replaced.

But for a modern car, a resource of 200 thousand is already not bad. After all, here we are talking only about a turbocharger, while a turbodiesel itself can easily last about 1 million kilometers.

By knowing the weak points of TDI, which are the injectors, turbine and dependence on the quality of diesel fuel, serious malfunctions can be prevented. To do this you need to follow a few simple rules.

Change your oil on time. Use engine oil only in accordance with the vehicle manufacturer's requirements and refill it at the specified intervals. Taking into account the weather and road conditions of our country, it is worth subtracting at least 20% from the replacement period recommended in the operating manual, and changing the oil a little more often. This will allow you to maintain the performance of the turbo engine, efficiently lubricate and cool the internal parts and rubbing surfaces. This extends service life and minimizes potential malfunctions.
Be sure to change the air filter. The operation of the turbine and the entire engine is greatly influenced by the quality of air purification. To prevent large amounts of debris from accumulating, try to periodically check the condition of the air filter. If it is heavily clogged, it is not recommended to try to clean it. The best solution would be replacement. In addition, the consumable is far from the most expensive, and such a replacement will not entail large expenses.
Check the boost pressure. This can be done during scheduled maintenance, as well as when replacing consumables during a visit to a car service center. Although for some it will not be difficult to check the pressure in the turbocharging system with their own hands. Such diagnostics will allow you to timely identify possible problems with the turbine, perform some repair work and extend the life of the compressor. If the turbine is almost worn out and its service life is coming to an end, it will have to be replaced completely. The pleasure is not the cheapest, but the TDI can last at least several more years without any serious and expensive malfunctions.
Refuel at proven gas stations with high-quality diesel fuel. The recommendation may seem banal and obvious, but it is this rule that is most often ignored by domestic owners of cars with TDI turbo engines. But fuel is the main cause of all the problems and malfunctions associated with an objectively excellent diesel engine. By not sparing money on more expensive, clean and safe diesel fuel, you will save significantly on the repair and maintenance of your TDI.

For all its advantages, the TDI design does not allow you to carry out a number of repairs on your own. It is not recommended to take risks and interfere with the design of a turbodiesel without the appropriate skills, experience and knowledge. It is better to get serviced at specialized car services, where they are perfectly familiar with all the nuances of TDI and will be able to carry out high-quality diagnostics and repair work.

TDI engines have become a real breakthrough in the world of diesel power plants. Moreover, the developers do not stop at the success achieved. They hold landmark records in terms of efficiency and environmental friendliness. Although such engines slightly increase the starting cost of the car, they are an excellent alternative not only to conventional diesel engines, but also to modern gasoline engines. Therefore, sometimes it is better to pay more, but get a motor with the abbreviation TDI under the hood.

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TDI engines - what are they? Features, characteristics

Until recently, diesel engines were used only in commercial vehicles. Such engines in passenger cars are a real curiosity for Russian car enthusiasts. Previously, foreign manufacturers (including VAG) did not officially supply such engines to the domestic market. But now cars and crossovers from Volkswagen with a TDI engine have begun to appear. What it is? Let's look at it in our article.

Characteristic

First, we note that engines with this abbreviation are found not only on Volkswagens.

Audi also has these units. TDI engines are engines with turbocharged diesel injection (hence the abbreviation). These units are also distinguished by the direct supply of Common Rail fuel.

Peculiarities

The main feature is the turbine that is equipped with the TDI engine. What it is? This is a mechanism that provides forced air supply, thereby increasing the torque and power of the motor. But unlike other engines, the 2.0 TDI has a special turbine design - with variable geometry. How is it different from conventional compressors? This design allows you to regulate the magnitude and direction of the exhaust gas flow. This gives a significant increase in power and high fuel efficiency. So, from two liters of volume you can get up to 170 horsepower. And thanks to the direct injection system, fuel consumption is about 5.5 liters in the combined cycle.

Some TDI engines in Volkswagen are equipped with a VNT turbine.

This abbreviation means that it is a compressor with a variable nozzle. The supplier of such turbines for Volkswagen is Garrett. The design of this unit assumes the presence of:

Vacuum drive.
Control mechanism.
Guide vanes.

TDI and Audi TT

Ecologically pure

What are the advantages of the TDI engine?

High fuel efficiency.
Low noise level (almost inaudible at idle).
High dynamics and torque.

Also, these power plants meet modern environmental requirements (Euro 6 exhaust standard). A significant increase in power was achieved thanks to the special design of the turbine. Unlike other engines, compressors from VAG units are capable of operating at a pressure of 2 thousand bar.

Modern analogues produce only 1300 Bar. Also in TDI engines the injector is combined with a pump. This allows for maximum control over fuel injection.

Conclusion

TDI engine ( Turbocharged Direct Injection, literally - turbocharger and direct injection) is a modern turbocharged diesel engine. The engine was developed by the Volkswagen Group, and the TDI name is a registered trademark.

Turbocharging of the TDI engine ensures high vehicle dynamics, efficiency and environmental safety.

To create optimal boost pressure over a wide range of speed conditions, the engine design uses a turbocharger with variable turbine geometry. Turbocharger has two common names, which are used by different manufacturers:, VGT Variable Geometry Turbocharger
(literally – variable geometry turbocharger) uses BorgWarner;, VNT Variable Nozzle Turbine (

literally - variable nozzle turbine) is used by Garrett.

Unlike a conventional turbocharger, a variable geometry turbocharger can regulate the direction and magnitude of exhaust gas flow, thereby achieving the optimal turbine speed and, accordingly, compressor performance.

The VNT turbine combines guide vanes, a control mechanism and a vacuum drive. The guide vanes are designed to change the speed and direction of the exhaust gas flow by changing the size of the channel cross-section. They rotate at a certain angle around their axis.

The blades are rotated using a control mechanism. The mechanism consists of a ring and a lever. The control mechanism is activated by a vacuum drive acting through a rod on the control lever. The operation of the vacuum drive is regulated by a boost pressure limiting valve connected to the engine management system.

The boost pressure control valve is activated depending on the boost pressure measured by two sensors: the boost pressure sensor and the intake air temperature sensor.

Working principle of supercharging a TDI engine exhaust gas energy is low. To use it effectively, the guide vanes are in the closed position, in which the exhaust gas channel area is smallest. Due to the small cross-sectional area, the flow of exhaust gases is enhanced and causes the turbine to rotate faster. Accordingly, the compressor wheel rotates faster, and the performance of the turbocharger increases.

With a sharp increase in engine speed, due to the inertia of the system, the energy of the exhaust gases becomes insufficient. Therefore, to pass through the “turbo lag,” the blades rotate with some delay, thereby achieving the optimal boost pressure.

At high engine speeds exhaust gas energy is maximum. To prevent excess boost pressure, the blades are rotated to a maximum angle, providing the largest cross-sectional area of the channel.

We present to your attention an overview of the most popular diesel engines of the Volkswagen concern.

1.9 TDI

Short description.

4-cylinder;

8 valve;

Pump injectors or direct injection;

With turbocharger;

Designed for small, compact or middle class cars.

This power unit was not the first “TDI” on the market, but it was the one that contributed to the fact that VW diesel engines became known almost all over the world. It was first used in the Audi 80 B4 in 1991. The 90-horsepower version of the 1.9 TDI turned out to be exemplary in its class. The car reached hundreds in less than 15 seconds and consumed about 5.5 liters per 100 km. In practice, this made it possible to travel 1200 km without refueling. An additional advantage was the absence of starting problems at low temperatures (typical of engines with direct fuel injection), as well as excellent reliability.

The 1.9 TDI was created on the basis of the 1.9 TD. The main differences: a new head and power system. Direct fuel injection from the injection pump is a key element in improving efficiency.

Higher power versions soon appeared - the most common being the 110-horsepower version. The engine went to the most popular models of the German concern: Audi, Seat, Skoda and Volkswagen.

In 1998, the next generation of the 1.9 TDI PD power unit entered the market. It is distinguished by the use of pump injectors, which replaced the classic scheme - injectors plus high-pressure fuel pump. The new solution made it possible to increase the injection pressure. This has further reduced fuel consumption and improved performance. However, there was a small side effect - a slight increase in operating costs.

The only drawback of the 1.9 TDI and 1.9 TDI PD is its rather noisy operation. Fortunately, this is only felt in lower class cars, and mainly at low speeds. When driving at a speed of about 100 km/h - due to various acoustic noises - the sound of the engine is no longer distinguishable.

It is worth noting that to reduce vibrations, the manufacturer used special engine mounts - oil-filled cushions. Cheap substitutes are made of rubber and metal, and therefore greatly reduce the level of comfort.

Interesting fact. The 1.9 TDI is easy to tune. Simple manipulations with the software can increase output by 20-30 hp. Specialists can easily double the maximum power.

Even the first 1.9 TDI is considered very durable. However, after 300,000 km, the first signs of aging appear: oil consumption increases, smoke appears when adding gas, oil leaks are observed, and power drops slightly. The newer 1.9 TDI PD is slightly less reliable, but compared to modern diesel units it is a role model.

Worn exhaust gas recirculation valve.

Typical symptoms of EGR valve failure are a drop in power, smoke, and sometimes a characteristic thud from under the hood. Repair comes down to diagnosing and eliminating related problems, and then replacing the element with a new one (cost about $100).

Wear of hydraulic valve tappets.

Noisy engine operation will indicate wear on the hydraulic tappets. Owners do not notice this, since the extraneous sound gradually increases from year to year, but fuel consumption and power do not change. The only cure is to install new ones. It is best to do this in conjunction with servicing the timing drive, since it will still have to be removed to replace it. One pusher costs about $6, and there are 8 in total.

Worn double flywheel.

A characteristic ringing sound when the engine is turned off indicates wear on the flywheel. Sometimes a metallic noise is also heard at idle. In such a situation, all that remains is to spend about $600 and replace the complete clutch kit along with the flywheel. It is worth noting that not all 1.9 TDI engines are equipped with a dual-mass flywheel. For example, the older 1Z does not have it.

Technical specifications 1.9 TDI – part I.

Versions	1.9 TDI 75	1.9 TDI 90	1.9 TDI 110	1.9 TDI PD 75	1.9 TDI PD 90
Supply system	injection pump	injection pump	injection pump	pump injectors	pump injectors
Working volume	1896 cm3	1896 cm3	1896 cm3	1896 cm3	1896 cm3
Cylinders/valves	R4/8	R4/8	R4/8	R4/8	R4/8
Max. power	75 hp / 4000	90 hp / 4000	110 hp / 4000	75 hp / 4000	90 hp / 4000
Max. torque	150 Nm / 1500	202 Nm / 1900	235 Nm / 1900	210 Nm / 1900	210 Nm / 1800-2500
Timing drive	toothed belt	toothed belt	toothed belt	toothed belt	toothed belt

Technical specifications 1.9 TDI – part II.

Versions	1.9 TDI PD 90	1.9 TDI PD 101	1.9 TDI PD 101	1.9 TDI PD 105
Supply system	pump injectors	pump injectors	pump injectors	pump injectors
Working volume	1896 cm3	1896 cm3	1896 cm3	1896 cm3
Cylinders/valves	R4/8	R4/8	R4/8	R4/8
Max. power	90 hp / 4000	101 hp / 4000	101 hp / 4000	105 hp / 4000
Max. torque	240 Nm / 1900	240 Nm / 1800-2400	250 Nm / 1900	240 Nm / 1800
Timing drive	toothed belt	toothed belt	toothed belt	toothed belt

Technical specifications 1.9 TDI – part III.

Versions	1.9 TDI PD 105	1.9 TDI PD 131	1.9 TDI PD 131	1.9 TDI PD 150
Supply system	pump injectors	pump injectors	pump injectors	pump injectors
Working volume	1896 cm3	1896 cm3	1896 cm3	1896 cm3
Cylinders/valves	R4/8	R4/8	R4/8	R4/8
Max. power	105 hp / 4000	131 hp / 4000	131 hp / 4000	150 hp / 1900
Max. torque	250 Nm / 1900	285 Nm / 1750-2500	310 Nm / 1900	320 Nm / 1900
Timing drive	toothed belt	toothed belt	toothed belt	toothed belt

Application.

Audi A3 I - 09.1996-05.2003;

Audi A3 II - 05.2003-05.2010;

Audi A3 Sportback - 09.2004-05.2010;

Audi 80 B4 - 09.1991-12.1994;

Audi A4 B5 - 01.1995-11.2000;

Audi A4 B6 - 11.2000-12.2004;

Audi A4 B7 - 11.2004-06.2008;

Audi A6 C4 - 06.1994-10.1997;

Audi A6 C5 - 04.1997-01.2005;

Seat Ibiza II - 08.1996-08.1999;

Seat Ibiza III - 08.1999-02.2002;

Seat Ibiza IV - 02.2002-11.2009;

Seat Leon I - 11.1999-06.2006;

Seat Leon II - 07.2005-09.2012;

Seat Toledo I - 08.1995-03.1999;

Seat Toledo II - 04.1999-05.2006;

Seat Toledo III - 10.2004-05.2009;

Seat Altea - 04.2004-03.2010;

Seat Alhambra I - 04.1996-3.2010;

Skoda Fabia II - 04.2007-03.2010;

Skoda Octavia I - 09.1996-03.2010;

Skoda Octavia II - 06.2004-12.2010;

Skoda Superb I - 12.2001-03.2008;

Skoda Superb II - 03.2008-03.2010;

Skoda Roomster - 03.2006-03.2010;

Volkswagen Polo 9N - 10.2001-11.2009;

Volkswagen Golf III - 09.1993-08.1997;

Volkswagen Golf III Cabriolet - 08.2005-06.2002;

Volkswagen Golf IV - 08.1997-06.2005;

Volkswagen Golf V - 10.2003-11.2008;

Volkswagen Golf Plus - 01.2005-01.2009;

Volkswagen Touran - 02.2003-05.2010;

Volkswagen New Beetle - 01.1998-06.2004;

Volkswagen Passat B4 - 10.1993-08.1996;

Volkswagen Passat B5 - 08.1996-05.2005;

Volkswagen Passat B6 - 03.2005-11.2008;

Volkswagen Sharan I - 09.1995-03.2010.

Ford Galaxy I, I FL: 03.1995-05.2006.

Volkswagen jealously guarded its successful powertrains and did not provide them to competitors. The only exception to this rule was the first generation Ford Galaxy. The car was a technical twin of the VW Sharan and Seat Alhambra and therefore received a wide range of TDI diesel engines with 90, 110, 115, 130 and 150 hp.

Conclusion.

This is one of the best engines in the history of the automotive industry. It is economical, and in more powerful versions – dynamic. Its main advantages are durability and inexpensive repairs. An alternative to it could be the 2.0 TDI CR.

1.4 TDI

Short description.

3-cylinder;

6 valve;

Injectors;

Turbocharger;

Designed for small city cars.

The 1.4 TDI (namely the 1.4 TDI PD) was created from the 1.9 TDI PD engine by “removing” one cylinder. The power unit debuted in the small Volkswagen Lupo. Quite quickly it found its way into other, larger models of the Volkswagen concern. It is most often found in the Audi A2, Seat Ibiza, Skoda Fabia and VW Polo.

This engine exhibits the greatest risk of malfunctions in export Skoda Octavias, especially in station wagons. The fact is that this particular car was often used in corporate garages. And there, as you know, cars are used harshly and carelessly. This greatly affects the condition of the motor.

Most car enthusiasts believe that the noisy 1.4 TDI PD is the optimal alternative to the naturally aspirated 1.9 SDI (it is not included in the review because it practically does not break down). Thanks to turbocharging, the 1.4-liter unit has better elasticity and greater efficiency. Real diesel fuel consumption on the highway is about 4 l/100 km, in the city - about 6.5 l.

Operation and typical malfunctions.

Just like the 1.9 TDI PD, the small 1.4 TDI PD has a cast iron block, aluminum head, timing belt and unit injectors. When used skillfully, it turns out to be practically trouble-free. In popular corporate cars (Skoda Fabia Combi, Roomster), the first signs of serious wear appear after 200,000 km - the result of full use.

Wear of pump injectors.

Symptoms are uneven engine operation and the glow plug indicator lights up while driving. Before deciding to replace or restore injectors, it is necessary to conduct a thorough diagnosis and eliminate wear of other elements of the fuel system.

Turbocharger wear.

A typical malfunction under high mileage and harsh operating conditions. Repairing the turbocharger of the 90-horsepower version is more expensive due to the variable geometry.

Technical specifications 1.4 TDI.

Versions	1.4 TDI PD 70	1.4 TDI PD 75	1.4 TDI PD 90
Supply system	pump injectors	pump injectors	pump injectors
Working volume	1422 cm3	1422 cm3	1422 cm3
Cylinders/valves	R3/6	R3/6	R3/6
Max. power	70 hp / 4000	75 hp / 4000	90 hp / 4000
Max. torque	155 Nm / 1600-2800	195 Nm / 2200	230 Nm / 1900
Timing drive	toothed belt	toothed belt	toothed belt

Application.

Audi A2 - 02.2002-08.2005;

Seat Arosa - 01.2000-06.2004;

Seat Ibiza III - 05.2002-11.2009;

Seat Ibiza IV - 07.2008-06.2010;

Seat Cordoba II - 10.2002-11.2009;

Skoda Fabia I - 01.2000-03.2008;

Skoda Fabia II - 01.2007-03.2010;

Skoda Roomster - 07.2006-03.2010;

Volkswagen Lupo - 01.1999-07.2005;

Volkswagen Fox - since 04.2005.

Conclusion.

This is a very economical engine. Its main drawback is uncomfortable work. It does not have a particulate filter, and therefore is best suited for the city. An alternative could be the junior 1.2 TDI, but it is more expensive to repair.

2.0 TDI

Short description.

4-cylinder;

8 or 16 valve;

Pump injectors or Common Rail;

Turbocharger;

Designed for compact and mid-class cars.

The 2.0 TDI is the successor to the popular 1.9 TDI. It was planned that he would repeat the success of his predecessor. But, unfortunately, this did not happen. The engine debuted in 2003 in an 8-valve version. In terms of technical parameters, the power unit has become better in all respects.

It gained notoriety under the hood of the Volkswagen Passat B6, where it proved to be very unreliable. However, a few years later the 2.0 TDI PD was offered in all VW models. Volkswagen even lent it to other manufacturers.

It is worth noting that the general name 2.0 TDI PD hides several different engine modifications. They differ in the degree of boost and technical details, such as the number of valves, the design of auxiliary equipment and even the layout of the lubrication system. It is for this reason that some models with 2.0 TDI PD do not bother their owners, while others, especially the Passat B6, constantly upset.

At the end of 2007, Volkswagen thoroughly modernized the power unit. The pump injectors were replaced with a Common Rail power supply system and most of the defects were eliminated. But the main reason for the reconstruction is the tightening of environmental standards and the reduction of production costs. Common Rail provides greater opportunities to control valve timing and injection. In addition, it is cheaper to produce.

The market is dominated by two CR versions - 140 and 170 hp. Interestingly, the Volkswagen diesel engine with pump injectors was also offered in two boost options - 140 and 170 hp. Therefore, at first glance, it is difficult to understand from the technical parameters which engine we are talking about.

Operation and typical malfunctions.

The reliability of the 2.0 TDI depends not only on operating conditions, but also on its version. Each option has its own code designation. It is included in the service book and is also indicated on the information plate, which is located in the trunk - in the niche for the spare wheel. The best reputation is enjoyed by the engine with the designation BKD, which was installed in the Audi A3 II, Skoda Octavia II, Seat Leon II, VW Golf V. The worst reviews were earned by the BKP series engine, used in the Passat B6.

Failure of pump injectors.

The injectors of the 2.0 TDI PD engines fail slightly more often than in the 1.9 TDI PD. But the worst thing is that they are more expensive. There are two types of injectors - Bosch and Siemens. The former cost about $250, the latter about $400.

Oil pump malfunction.

In some versions of the 2.0 TDI PD, such as the previously mentioned BKP, the oil pump drive wears out prematurely. As a result, the oil pump may fail, resulting in damage to the turbocharger and seized bearings. The oil pressure indicator will indicate that there is a problem, but this usually means it is too late. The pump drive can be repaired or replaced with a new one (about $500). However, this is a temporary solution. After such a malfunction, it is better to replace the engine, for example with a 2.0 TDI PD from Skoda Octavia II or VW Golf V.

Block head cracking.

In some versions of the 2.0 TDI PD, head damage often occurs. The defect affects 16-valve modifications. Repair is difficult and does not guarantee success. New heads cost between $500 and $800.

Particulate filter malfunctions.

In 2.0 TDI PD engines there are 2 types of DPF filters: dry and wet. The latter type was common in the Passat B5 FL Skoda Superb versions and was not particularly reliable.

Technical data 2.0 TDI – part I.

Versions	2.0 TDI PD	2.0 TDI PD	2.0 TDI PD	2.0 TDI PD
Supply system	pump injectors	pump injectors	pump injectors	pump injectors
Working volume	1968 cm3	1968 cm3	1968 cm3	1968 cm3
Cylinders/valves	R4/8	R4/16	R4/8	R4/16
Max. power	136 hp / 4000	136 hp / 4000	140 hp / 4000	140 hp / 4000
Max. torque	335 Nm / 1750	320 Nm / 1750	320 Nm / 1800-2500	320 Nm / 1750-2500
Timing drive	toothed belt	toothed belt	toothed belt	toothed belt

Technical data 2.0 TDI – part II.

Versions	2.0 TDI PD	2.0 TDI CR	2.0 TDI CR	2.0 TDI CR
Supply system	Injectors	Common Rail	Common Rail	Common Rail
Working volume	1968 cm3	1968 cm3	1968 cm3	1968 cm3
Cylinders/valves	R4/16	R4/16	R4/16	R4/16
Max. power	170 hp / 4200	110 hp / 4200	140 hp / 4200	170 hp / 4200
Max. torque	350 Nm / 1800-2500	250 Nm / 1500-2500	320 Nm / 1750-2500	350 Nm / 1750-2500
Timing drive	toothed belt	toothed belt	toothed belt	toothed belt

Application.

Currently, the 2.0 TDI engine is one of the most popular power units in Volkswagen models. In the compact class it can act as a sports power unit, for example the Seat Ibiza Cupra, and in the middle class it serves as a base unit, for example in the Passat.

Audi A3 II - 03.2003-03.2013;

Audi A3 II Sportback - 05.2004–03.2013;

Audi A4 B7 - 2004-2008;

Audi A4 B8 – from 09.2007;

Audi A6 C6 - 07.2004-03.2011;

Audi A6 C7 – from 10.2013;

Chrysler Sebring III - 03.2007-04.2009;

Mitsubishi Outlander II - 02.2007-10.2010;

Seat Ibiza IV – from 10.2009;

Seat Leon II - 2005-2012;

Seat Leon III – from 11.2012;

Seat Toledo III - 2004-2009;

Seat Altea - 03.2004-09.2010;

Seat Exeo - 04.2009-05.2013;

Seat Alhambra I FL - 10.2005-08.2010;

Seat Alhambra II – from 05.2010;

Skoda Octavia II - 06.2004-01.2013;

Skoda Superb I - 2004-2008;

Skoda Superb II – from 06.2008;

Skoda Yeti – since 2009;

Volkswagen Golf V - 08.2003-05.2009;

Volkswagen Golf Plus I, II – from 12.2004;

Volkswagen Golf VI - 10.2008-10.2012;

Volkswagen Golf VII - from 08.2012;

Volkswagen Beetle – from 02.2012;

Volkswagen Passat B5 FL - 11.2003–05.2005;

Volkswagen Passat B6 - 02.2005-07.2010;

Volkswagen Passat B7 – from 11.2010;

Volkswagen Tiguan – since 08.2007;

Volkswagen Touran I - 01.2003-05.2010;

Volkswagen Touran II – from 05.2010;

Volkswagen Scirocco – from 07.2008;

Volkswagen Sharan II - 10.2005-08.2010;

Volkswagen Sharan III – from 05.2010.

The 2.0 TDI engine was also installed in cars from other manufacturers:

Chrysler Sebring III;

Dodge Avenger, Caliber;

Jeep Compas;

Mitsubishi Grandis, Lancer VIII, Outlander II.

Conclusion.

The 2.0 TDI PD engine deserves very low ratings. In terms of performance, it's not bad, but its reliability calls into question the brand's reputation. The engine with the Common Rail power system deserves positive reviews.

2.5 TDI V6

Short description.

6-cylinder;

24-valve;

Direct injection;

Turbocharger;

Designed for middle class cars and above.

Market realities of the 90s forced VW to develop a modern diesel V-twin engine. Further improvement of the utilitarian 5-cylinder unit did not make any sense. This is how the 2.5 TDI V6 appeared - the first diesel V6 of the Volkswagen concern.

This engine debuted in 1997, initially in the Audi A8. The block was cast from cast iron, and the two heads were made from aluminum. The power unit received a gas distribution system unusual for that time: 4 valves per cylinder and only 4 camshafts (2 per head). The system was driven by a complex arrangement of timing belts. The main belt drove only the intake shafts, while the exhaust shafts had a separate belt. Fuel was supplied using a Bosch injection pump. This turbodiesel never had a particulate filter, and the EGR valve appeared only in a version that complies with the Euro-4 environmental standard.

Operation and typical malfunctions.

The 2.5 TDI V6 engine has a terrible reputation, which it quickly earned in the early 150 hp version. Later modifications with a power of 155-179 hp. have proven themselves to be much better. The BAU and BCZ models are worthy of recommendations.

Shaft wear.

This is the main problem with the 150 hp TDI V6. Wear on the shaft cams causes the engine to run more and more unevenly. Eventually, the shafts will have to be removed and subjected to a restoration process. This will require about $1000.

Pump failure V.P.

A technically advanced fuel injection pump with electronic control is prone to malfunctions due to a malfunction of the controller, or rather the fuel quantity calibration sensor. A new pump costs about $300. There are no analogues.

Oil leaks.

To eliminate oil leaks through the seals, it is usually necessary to remove the engine. You will have to spend almost 500-700 dollars on repairs.

Clogged crankcase ventilation system.

The appearance of white smoke and loss of power may indicate a clogged crankcase ventilation. It will cost about $70 to replace. For preventive purposes, it is better to carry it out every 50-60 thousand km.

Technical specifications 2.5 TDI V6.

Versions	2.5 TDI	2.5 TDI	2.5 TDI	2.5 TDI
Supply system	direct injection	direct injection	direct injection	direct injection
Working volume	2496 cm3	2496 cm3	2496 cm3	2496 cm3
Cylinders/valves	V6/24	V6/24	V6/24	V6/24
Max. power	150 hp / 4000	155 hp / 4000	163 hp / 4000	179 hp / 4000
Max. torque	310 Nm / 1400-3200	310 Nm / 1400-3200	310 Nm / 1400-3600	370 Nm / 1500-2500
Timing drive	toothed belt	toothed belt	toothed belt	toothed belt

Application.

Audi A8 D2 - 01.1997-2002;

Audi A6 C5 - 07.1997-01.2005;

Audi A4 B5, B6 - 09.1997-12.2004;

Volkswagen Passat B5 - 07.1998-05.2005;

Skoda Superb I - 12.2001-03-2008.

Conclusion.

The first experiment failed. Many other manufacturers also tried to create the perfect diesel V6, but without success. You should stay away from the 150 hp version. Options with a power of 163 and 179 hp are worthy of recommendations, but only those that comply with the Euro-3 standard. Later engines are troublesome. A good alternative would be petrol V6s.

2.7 and 3.0 TDI

Short description.

6-cylinder;

24-valve;

Common Rail direct injection;

Turbocharger;

Designed for middle-class and higher cars, SUVs.

The 2.7 and 3.0 TDI V6 engines were developed from scratch and have nothing in common with the old V6 2.5 TDI. These are modern turbodiesels with a Common Rail injection system and a system of three timing chains located in an inconvenient place - on the gearbox side. These engines provide fantastic performance and consume noticeably less fuel than the 2.5 TDI when driving quietly.

The 3-liter TDI debuted in 2004 in the Audi A8. It drew admiration from journalists and customers, who noted its fantastic dynamic performance. The power unit has a cast iron block and cylinders spaced at an angle of 90 degrees. In addition to a set of timing chains that drive the shafts, there is a timing belt that drives the Common Rail high-pressure pump, which generates a pressure of 1,600 bar. Fuel is supplied to the cylinders by Bosch piezoelectric injectors. The engine had two intercoolers located on the sides. The 2.7-liter unit featured a piston stroke reduced by 8 mm. All V6 TDIs with common rail have a DPF filter.

Most TDI models with more than 6 cylinders, such as the 4.2 TDI and 6.0 TDI, are obtained by increasing the number of cylinders. This does not apply to the 10-cylinder unit (known from the VW Touareg), which is de facto a combination of two 2.5-liter inline-fives.

Operation and typical malfunctions.

The technically complex 3.0 TDI requires a lot of effort and money for any repair. Here we are dealing with a “pack of equipment” that increases the cost of ownership. Unfortunately, the TDI CR V6 is practically unable to travel 300,000 km without repair. Often, serious problems begin to appear after 150,000 km.

Timing drive.

In many cars, the timing chain tensioner causes trouble. This manifests itself as a grinding noise upon startup. There is no point in delaying repairs. A comprehensive timing belt replacement with new tensioners will cost $2000-2500. Fortunately, there are few cases of chain jumping, but if this happens, a major engine overhaul will be required.

Piston burnout.

The first batches of 3.0 TDI were equipped with piezoelectric injectors, which quickly failed. They ensured that there was not enough fuel supplied to the cylinders. As a result, a mixture that was too lean led to an increase in temperature and burnout of the pistons.

Technical specifications 2.7 TDI.

Versions	2.7 TDI	2.7 TDI	2.7 TDI
Supply system	Common Rail	Common Rail	Common Rail
Working volume	2698 cm3	2698 cm3	2698 cm3
Cylinders/valves	V6/24	V6/24	V6/24
Max. power	180 hp / 3300	190 hp / 3500	204 hp / 3500
Max. torque	380 Nm / 1400-3500	400 Nm / 1400-3500	450 Nm / 1400-3500
Timing drive	chain	chain	chain

Technical specifications 3.0 TDI.

Versions	3.0 TDI	3.0 TDI	3.0 TDI	3.0 TDI	3.0 BiTDI
Supply system	Common Rail	Common Rail	Common Rail	Common Rail	Common Rail
Working volume	2967 cm3	2967 cm3	2967 cm3	2967 cm3	2967 cm3
Cylinders/valves	V6/24	V6/24	V6/24	V6/24	V6/24
Max. power	224 hp / 4000	233 hp / 4000	240 hp / 4000	245 hp / 4000	313 hp / 3900
Max. torque	450 Nm / 1400-3250	450 Nm / 1400-3250	500 Nm / 1400-3500	580 Nm / 1400-3250	650 Nm / 1450-2800
Timing drive	chain	chain	chain	chain	chain

Application.

Audi A4 B7, B8 - from 11.2004;

Audi A5 – from 06.2007;

Audi A6 C6, C7 – from 05.2004;

Audi A7 – from 10.2010;

Audi A8 D3, D4 – from 01.2004;

Audi Q5/SQ5 – from 11.2008;

Audi Q7 – from 03.2006;

Porsche Cayenne I - 02.2009-06.2010;

Porsche Cayenne II – from 06.2010;

Volkswagen Phaeton - from 09.2004;

Volkswagen Touareg I - 11.2004-01.2010;

Volkswagen Touareg II – from 01.2010.

Conclusion.

An excellent choice for those who do not have to consider operating costs. If you're buying a diesel to save money, then stay away from the 3.0 TDI. A good alternative would be the V6 3.0 TSI petrol engine.

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