Motors of the TDI family are a line of power units produced by the German auto giant Volkswagen. Diesel engines designated by the abbreviation TDI (from the English. Turbocharged Direct Injection) are units with a turbocharger and are equipped with a direct fuel injection system. These 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
History of the TDI engine
diesel engine has always attracted various companies with its untapped potential. The main task that was set before the engineers was the transformation of a noisy, low-speed and low-speed unit into such 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 terms of its performance, was as close as possible to a gasoline power unit.
The pioneer in this direction was Audi, which back in 1980 installed a 1.6-liter diesel 54-horsepower aspirated engine under the hood of its popular Audi 80 model. launched into mass production a compact, high-torque and powerful turbodiesel engine, which received the designation TDI, which is widely known today.
The first TDI was a 5-cylinder diesel engine with a displacement of 2.5 liters and was equipped with a turbocharger with an intercooler (air aftercooling system). The maximum power of this motor was 120 hp. The torque indicator was at around 256 Nm and was reached at the output of 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 the WAG, the Volkswagen concern took the first position in the list of diesel engine manufacturers. Innovative engineering solutions and proven production technologies have provided TDI engines with:
- low noise level during operation;
- high torque;
- low fuel consumption;
- reduction of toxicity of exhaust gases;
Today, the TDI diesel engine, compared with its counterparts, has a number of advantages, among which fuel efficiency and are separately distinguished. One of the main advantages is deservedly considered a higher injection pressure compared to the performance of other systems. The injection pressure in TDI engines is at around 2050 bar, while analogues give out only 1350 bar.
In the TDI, the injector is integrated with the 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 process of diesel fuel combustion 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 fallen. In other words, the diesel TDI engine is powerful, quiet, least harmful to environment and the most fuel-efficient diesel engine available on the market.
Reliability of diesel TDI
Also in some designs of power systems for diesel internal combustion engines, you can find the so-called pump injectors. This means that each injection nozzle is equipped with its own pump. high pressure. It turns out that the development of diesel technology today is reduced to an increase in injection pressure and the maximum efficiency of the turbocharging system. So it is possible to solve the main tasks: to increase power and reduce the level of toxicity of exhaust gases.
Turbocharging TDI: variable geometry turbine
The efficiency of the TDI turbocharging largely determines not only dynamics, but also economy and environmental friendliness. Proper air intake must be implemented in the widest possible range. For this reason, a turbocharger with variable turbine geometry is installed on TDI engines.
The leading turbine manufacturers in the world use the following names:
- Turbine VGT (from the English. Variable Geometry Turbocharger, which means a variable geometry turbocharger). Manufactured 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 the amount of exhaust gas flow. This feature allows you to achieve the most appropriate turbine speed in relation to a specific mode of operation of the internal combustion engine. The performance of the compressor in this case is greatly increased.
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. Said turbine blades rotate by the required angle around their axis, thereby being able to change the speed and direction of the exhaust flow. This is due to a change in the cross section of the channel.
The control mechanism is responsible for the rotation of the blades. Structurally, the mechanism has a ring and a lever. The lever is affected by a vacuum actuator, which controls the operation of the mechanism through a special thrust. The vacuum drive is controlled by a separate valve that limits the boost pressure. The valve is an integral element of the internal combustion engine electronic control system and works depending on the indicators of 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 flow rate (energy) of the exhaust is quite low. In this mode, the guide vanes are usually closed, which achieves the minimum cross section in the channel. As a result of passing through such a channel, even a small amount of gases turns the turbine more efficiently, causing the compressor wheel to rotate noticeably faster. It turns out that the turbocharger provides more performance at low revs.
- If the driver sharply presses the gas, then the conventional turbine has the effect of the so-called "turbo lag". A turbo lag should be understood as a delay in response to pressing the gas pedal, that is, not an instant increase in power, but a pickup 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 time 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 desired boost pressure and practically get rid of the turbo lag.
- When driving at high and close to the maximum engine speed, the exhaust gases have a maximum of energy. To prevent the creation of excessive boost pressure, the blades in turbines with variable geometry are rotated so that a powerful flow of gases moves along a wide channel with the largest cross section.
We know them as one of the most reliable and economical engines, Audi TDI turbodiesels have been evolving since 1989, when the first 2.5 TDI turbodiesel with direct fuel injection was installed on the Audi 100. From that moment to this day, Audi has produced more than 5 million engines under the letter TDI.
On the this moment, there are already many such engines.
2.5 TDI, 119hp (1989)
At the 1989 Frankfurt Motor Show, Audi introduced a five-cylinder 2.5-liter TDI diesel engine that was installed under the hood of the third generation Audi 100. At first, this engine produced 120hp. and 265 moments, but since 1994, after small improvements in the fuel injection system and exhaust gas recirculation, the power has already risen to 140 hp. In this version, the 2.5 TDI turbodiesel was installed for the first time on the first generation of the Audi A6. 
1.9 TDI, 90hp (1991)
After two years of producing the first diesel, Audi released its first four-cylinder TDI, which had exactly the same fuel injection system as its older brother. "Four" with a volume of 1.9 liters gave out 90 forces and 182 Nm. First of all, this engine was installed on the Audi 80 
, while he consumed only 4.0 liters. diesel fuel for 100 km. A little later, the Audi 100 could also be purchased with this engine.
1.9 TDI, 110hp (1995)
In 1995, the 1.9 TDI engine was slightly upgraded, with power up to 110hp. and 225 torque available already from 1,700 rpm. up to 3,000 rpm. This engine debuted on the Audi A4 and A6 models, as well as the Audi A3, in 1996. 
2.5 TDI, 150hp (1997)
In 1997, Audi launched its first six-cylinder TDI with four valves per cylinder. 2.5-liter V6 TDI, produced 150 hp and 310nm which was available from 1,400rpm. up to 3,200rpm Later, the power increased to 180 hp in the final version. The V6 TDI first debuted on the Audi A8, followed by the A4 and A6. 
1.4 TDI, 75hp (1999)
The smallest 1.4 TDI turbodiesel at that time was created specifically for the Audi A2, which debuted in 1999. The engine had 3 cylinders and two valves per cylinder, developing 75 forces in a weak version. and 195 moments, and in the most powerful all 90 hp. and 230 Nm of torque. 
3.3 TDI, 225hp (1999)
With a displacement of 3.3 liters, a power of 225 stallions and a torque of 480 Nm, the new V8 TDI with four valves per cylinder was the most powerful TDI at that time in the TDI range. For the first time it was installed on the company's flagship A8. 
1.9 TDI, 115hp (year 2000)
In 1999, the 1.9 TDI turbodiesel finally got a VTG (Variable Turbine Geometry) turbine, as well as an exhaust gas water cooling system. With these changes, 115 hp. and 285Nm already from 1,900 rpm. Later, three varieties of 1.9 TDI were released, with a capacity of 100, 104 and 130 hp, which were first installed on the Audi A4 models, and then on the A3 and A6. 
1.2 TDI, 61hp (year 2001)
The 1.2 TDI engine made the Audi A2 the first car in the world to consume less than 3 liters per 100 km. The average consumption of this version was 2.99 l / 100 km, and is unsurpassed to this day. The 3-cylinder engine was based on the 1.4-liter version, but thanks to the aluminum block, it only weighed 100kg! Due to the VTG variable geometry turbine and direct fuel injection, the motor produced 61 hp. and 140 Nm available from 1,400 rpm. up to 2,400 rpm. Even then, the Audi A2 was equipped with a start-stop system! 
2.0 TDI, 140hp (2003)
The new 2.0 TDI engine was based on the 1.9 TDI unit, but featured larger pistons, a new cylinder head with two camshafts and four valves per cylinder. The engine produced 140 hp. and 320 Nm, and was installed for the first time on the Audi A3 model, then on the A4 and A6 models. 
4.0 TDI, 275hp (2003)
The 4.0-litre V8 TDI engine has been fitted since 2003 in the Audi A8 models. Thanks to the "common rail" direct fuel injection system and two turbochargers, the diesel produced 275 hp. and 650 Nm of torque, and became the most powerful at that time. 
3.0 TDI, 204hp (2004)
Debuting for the first time in 2004, the 3.0 TDI engine was the first 90-degree V-engine to feature new piezo injectors. Power varied: 204 hp, 224 hp and 233 hp In the past five years, this engine, in all three versions, was installed on the A4, A5, Q5, A6 Allroad, A8 and Q7 models. At the moment, this unit produces 240 hp. and 500-550 Nm of torque. For the first time, 3.0 TDI was installed on the A6 and A8 models. 
2.7 TDI, 180hp (2004)
Immediately after the introduction of the 3.0 TDI version, the 2.7 TDI engine debuted at the end of 2004, which was based on the same technology as its older brother. At first, the 6-cylinder turbodiesel produced 180 hp. and 380 Nm, then the power increased to 190 hp. He first debuted on the Audi A6, and then it was installed on the A4 and A5. 
4.2 TDI, 326hp (2005 year)
Introduced in 2006 on the Audi A8 and Audi Q7 models, the 4.2 TDI produced 326 bhp. and 650 Nm. Now this engine is only available for the Audi Q7 model, but in the latest 4.2 TDI version, it already produces 340 hp. and 760 Nm. 
2.0 TDI, 143hp (2007)
In 2007, Audi released a new two-litre TDI. After optimizing the piston group, the diesel engine was able to spin up to 5,500 rpm.! Giving out 143 hp. and 320 Nm, the 4-cylinder diesel has become a bestseller on the market, thanks to the A3, A4 models, on which it is installed to this day. Optionally, a derated version of 120 hp is offered for the A4 model. 
3.0 TDI, 240hp clean diesel (2008)
Considered the TDI of the future, the 3.0 TDI clean diesel is so fuel efficient and environmentally friendly that it is eligible for Euro 6 emission regulations, which will come into effect in 2014. Emissions have been reduced to a large extent by the DeNox catalyst system, which cleans the exhaust gases by injecting AdBlue into the exhaust system. The 3.0 TDI clean diesel engine produces 240 hp. and 550 Nm. 
And our flagship is 6.0 TDI, 500hp (2008)
The 6.0 TDI, which is exclusive to the Audi Q7, has been the world's most powerful production turbodiesel since 2008. This V12 was based on the unit of the Audi R10 TDI racing car, which won the 24 Hours of Le Mans three times. Mind-blowing performance inspires respect and slight shivering - 500 hp. and 1,000 Nm of torque! 
I hope it was interesting =)
In heavy and powerful crossovers, the brakes are usually a very vulnerable node. For a car with a gross weight of 2,200 kg and a power of 300 hp or more. the braking system works in very harsh conditions, even with relatively active traffic in city traffic. What can we say about cases when the driver really “burns out” ... Everything is complicated by puddles on the roadway, ubiquitous sand, traffic jam - gas to the floor - traffic jam, and sometimes braking from a speed of over 200 on the highway.
Pictured: Audi Q7 3.0 TDI quattro (4L)" 2009–15
Brake discs with a diameter of 350 mm and six-piston calipers already cope with such a load to the limit. And therefore, for those who for some reason imagine themselves driving a racing car on a two-ton crossover, among the options offered were those who were not afraid of such a load, although they did not provide normal braking when unheated, not to mention the considerable price of such a solution.
The resource of brake pads and discs is a very modest 20-30 thousand kilometers, and the discs often go no longer than one set of pads. With “stepped” braking, accurate and calm movement and extremely professional use of brakes, the resource of discs and pads increases by two or three times, but most ordinary users of these machines had and still have complaints about the resource of brake system components.
“Travel losses” also include ABS sensor failures, damage to strut wiring, air spring housings, body level sensors, and rapidly aging brake fluid. Do not be surprised at non-original brake discs on a car with a mileage of up to 70-100 thousand, this is quite a typical case. The rest is nothing to complain about. The ABS works well, complaints about excessive braking in corners and on bumps are rare, it does not cut off the fixing pin, because it simply does not have time to rust between disk replacements, and the parking brake turned out to be quite reliable.
Suspension and steering
The suspension of a large crossover, and even claiming to be sporty, on wheels with "duct tape" should also not differ in a large resource even theoretically. In practice it is. A hundred thousand kilometers even in the city - and it's time to sort out the front suspension. It will require at least the replacement of the silent blocks of the lower arm and the upper ball joint. And if there is an optional “pneuma”, then the price of all problems increases by an order of magnitude, and the fee for negligence (i.e., an old dehumidifier, lack of weekly washing of air springs and checking wiring) can make up a substantial part of the price of a car of the first years of production. It is not surprising that Q7 before restyling often already have a “collective farm” in the form of a spring suspension instead of pneumatics, or they regularly go to pump up to gas stations, because the pump cannot cope with leaks or is out of order.
In the photo: Front suspension and brakes. 120 thousand kilometers.
Pneumatic strut
original price
According to some owners of Q 7, the car is better controlled on springs, but pneumatics is excellent comfort with quite tolerable handling, so it justifies its price. In general, if you are looking for a cheaper Q7, then I recommend that you think about whether you can also pull the regular costs of the suspension.
The steering was distinguished only by frequent rack drips and a short resource of steering tips, especially on cars with V 8 engines and low-profile tires. This is to be expected for city driving, with frequent steering wheel turns to lock and wheels spinning in place.
But the repair price is not comparable even with the prices for repairing suspensions and brakes, so the main risks in this case are not recognizing a leak in the rails and being left without a power steering away from services. Without the help of the amplifier, the steering wheel is extremely heavy - this can simply lead to an accident.
Transmission
From this side, special tricks can not be expected. The mechanical part of the transmission is very reliable, and the simplified design of the transfer case without reduction gear makes it even stronger. CV joints, cardan shafts and gearboxes are made with a good margin and can withstand everything except the 6.0 diesel. If they “anneal” with such a motor, then the shafts are literally twisted, the gearboxes are torn off the subframes, and the teeth are cut off. This is not to mention the automatic transmission resource.
Mechanical boxes, which are occasionally found with 3.6 engines and a 3.0 diesel engine, do not cause any special questions, except that the resource of a two-mass flywheel is limited to literally a hundred, one and a half hundred thousand mileage, and it costs a lot. Yes, and the clutch burns pretty quickly due to the suboptimal selection of gear ratios - the first gear is "long".
With automatic transmission, everything is quite expected and standard. With diesel engines 3.0, 4.2 and with most of the gasoline V 8 4.2, before restyling, they installed the Aisin TR 60SN box, the same one that can be found on the TLC 200 and platform Cayenne and Touareg. It has rather conservative settings and, with a calm driving style, has an impressive resource by modern standards for 250-300 thousand kilometers. Joy is overshadowed by the capricious valve body of the box, which is easily contaminated by wear products of the gas turbine engine blocking linings during active movement, which is typical for the style of use of such machines. In addition, the automatic transmission radiator is small, the oil regularly overheats to temperatures over 120 degrees, which increases the chances of problems.
Pictured: Interior of the Audi Q7 4.2 quattro (4L)" 2005–09 In general, even a reliable automatic transmission cannot work a miracle, and most drivers have problems associated with twitches and delays in switching after a run of 100-120 thousand kilometers. Fortunately, the design of this automatic transmission makes it possible, with a minimal (albeit expensive) repair, to restore the gas turbine engine and the full performance of the unit without mechanical breakdowns.
On cars with automatic transmission ZF 6HP 21 / 6HP 19, which were installed with 3.6 and 4.2 engines, everything is noticeably more complicated. These automatic transmissions were among the first where the gearbox control unit was moved inside the box itself, thus obtaining a unit called "mechatronics", and at the same time tried to reduce the operating pressure to a minimum. It turned out to be ambiguous.
The very aggressive use of the GDT slip lock, the sliding shifts of the main clutches, the use of mainly linear solenoids, made it possible to obtain impressive dynamics and economy. But the integrated design turned out to be very vulnerable to pollution and overheating, and with such strict operation algorithms, they simply cannot be avoided.
In general, in addition to the wear and tear of mechatronics, the problems of which are many times more expensive than those of a “regular” valve body and control system, there is a complete set of mechanical problems. Clutches wear out quickly due to the peculiarities of the algorithm, contamination and burning due to high temperatures, problems with oil pressure, wear of box bushings, damage to drums and planetary gears appear. And of course, the resource of the gas turbine engine is small, in the region of hundreds of thousands.
Pictured: Audi Q7 4.2 quattro (4L)" 2005–09 To the credit of this type of gearbox, they hold up to the toughest starts and races even better than the older Aisin transmission for a while, but then the inevitable reckoning comes in the form of expensive repairs and frequent failures. Moreover, in this case, five or six years is already a big age for the box, often it is already ready to go for a major overhaul.
With 6.0 engines, they also installed a reinforced version of this ZF 6HP 32 automatic transmission, and the gain was clearly not enough, because contract units are in short supply. The motor successfully "folds" the box already at a very low mileage. But gasoline sports cars will envy the dynamics - this cannot be taken away.
On cars after 2011, an eight-speed ZF automatic transmission of the 8HP 45 series with a start-stop function appeared. Even at such a ridiculous age, according to "transmission" standards, she managed to earn the glory of being superbly unreliable, having a phenomenally small resource and, moreover, extremely expensive and difficult to repair. Although we have to admit that the efficiency of the new 3.0 TFSI in combination with such a box is impressive.
For more information about the features of the operation of eight-stages, see here I will not dwell on these boxes in detail. Moreover, there are, fortunately, relatively few cars with this combination of engine and automatic transmission.
Motors
With Audi Q 7 engines, the situation is ambiguous. If you want a minimum of problems, take the 3.0 TDI and 4.2 TDI diesel options - they are the most common. Quite “average” in all respects, the VR 6 3.6 FSI gasoline for such a heavy machine, even in the most powerful modification, was rather weak, besides, difficulties with chains, not the most successful piston and power system left no chance for trouble-free operation. But against the background of a 4.2 FSI, 3.0 TFSI gasoline engine and the problems of cars with a 6.0 diesel engine, even this VR 6 looks good. Below are some details.
Timing chain 3.6 lower
original price
There are few common problems with motors. The cooling system on the Q 7 was made with a margin, only on older gasoline engines, the risks of leaks due to pipe cracking increase with age, and diesel engines generally feel great. I have already talked about the problems of electricians, except that diesel starters fail more often than usual, especially for some reason on restyled cars.
The "main" motor Q 7 is a series of 3.0 V 6 diesels in different versions. A completely successful “cast iron” has an intricate timing chain, similar to the extremely unsuccessful gasoline 4.2, but at a lower oil temperature and lower operating speeds, it lasts one and a half times more. Difficulties with injectors and the intake manifold, the presence of unsuccessful modifications of the injection pump against the background of other costs for the car usually do not cause a serious negative. Moreover, the dynamics are more than decent for a “car”, and fuel consumption of up to 14-15 liters per hundred can be considered outstanding.
In the photo: Under the hood of the Audi Q7 3.0 TDI quattro (4L) "2006–09 When buying, first of all, it is worth checking the fuel filters for chips. It is believed that cars after restyling with engines with the CASA index are subject to misfortune, but in practice, older engines suffer from the same ailment. As a result of problems with the high-pressure fuel pump, the entire fuel system becomes contaminated, and the replacement of the “culprit” itself no longer saves. Chips from the tank will disable the next set of nozzles and the pump - a comprehensive replacement or cleaning is necessary here.
Timing Belt/Injection Pump 3.0 TDI
original price
The intake manifold on pre-styling cars is another source of problems, but since they appeared with a run of up to 30-60 thousand, the chances of finding a car with this problem tend to zero. Well, except for purposefully looking for a car with a minimum mileage from the owner, who has not heard about recall campaigns ...
There are two turbines on this diesel engine, they have a large resource, they can withstand more than 150 thousand, if poured good oil and do not drive through puddles after “annealing” - hot “snails” corny crack when water gets in. The oil and antifreeze supply pipes require attention - corrosion, high temperature and dirt lead to leaks, and there it is not far from the capital of the motor.
Diesel 4.2 essentially differs from 3.0 a little. The resource is even higher, though the taxes will be higher. Unfortunately, the risks for the EGR system are increasing, and cylinder head corrosion is more pronounced. Well, do not forget that an automatic transmission with such an engine is very difficult - the resource is reduced by a good third, and the chances of problems with the mechanics of the box increase.
Audi Q7 3.0 TDI quattro (4.2 TDI quattro)
In the photo: Under the hood of the Audi Q7 4.2 TDI "2007–09 Gasoline VR 6 3.6 - perhaps the most successful of the gasoline engines. I have already mentioned the main difficulties with chains and a light oil burner, and all FSI engines have common problems with soot, injectors and fuel pumps. A small resource of ignition modules, oil leaks and a monstrous design of the cylinder head and intake are simply a consequence of layout decisions, and they are not serious shortcomings.
In the photo: 3.6 FSI engine (engine compartment prepared for repair work). But a good resource of the piston group, low fuel consumption, maintainability of the design and ease of maintenance of Q 7 with such an engine (even compared to diesel engines!) Are undoubted advantages. In some cases, a 3.6 petrol car may even be cheaper to operate than a diesel one.
Here are the 4.2 FSI engines - this is a real failure. In addition to power problems, there are also great chances for scuffing of the aluminum piston group, difficulties with intake tightness, with an oil pump, with an oil burner, with timing chains, attachments and a control system ... The saddest thing is that the problem cannot be solved with money - even replacing the engine with a new one , you only reduce the chances of problems with low mileage. "Happy" owners of new cars with runs up to 60 sometimes managed to replace two motors under warranty. Do you need it now, when the warranty is no longer valid, and the chances of a “kulanz” (extended warranty) are illusory? What if the cylinder block cracked?
The only case when buying a Q7 with 4.2 FSI justified - if the engine is already dying, and the owner offers a very good discount. After making sure that everything else is more or less in order (which is not always the case), you can buy a car purposefully under, since with relatively minor alterations, an older gasoline engine will fit here V8 from Touareg or Audi A8.
The brand new 3.0 TFSI became famous right away. The manufacturer attributed the seizures of the piston group to ... an unsuccessful thermostat. Of course, lowering the operating temperature of the motor reduces the risk of detonation and the load on the alusil coating, but apparently, the problem was simply postponed until after the warranty.
There were motor replacements, but most owners did not even receive an updated piston group, only firmware and a thermostat. Apart from the risk of failure, the motor looks like a miracle of modern technology. Excellent traction and power, and fuel consumption - as low as diesels, although given the difficulties with the piston, a car with 3.0 TFSI it is better to "feed" the AI-98.
Audi Q7 3.0 TFSI quattro (4.2 FSI quattro)
Claimed fuel consumption per 100 km
Pictured: Audi Q7 V12 TDI quattro (4L)" 2008–09 To take or not to take?
Once again, a phrase about the price of a yacht that you can’t afford climbs into your head. Audi's "second flagship" turned out to be very wasteful in operation, and the number of problems inherent in the design is quite significant. In the case of the Audi Q7 a cloudless future does not guarantee either a small age or a modest mileage, even if it is honest. You need to buy such a car with one of the “junior” diesel engines, choose and diagnose carefully, and still have hundreds of fifteen hundred rubles just “for expenses”. Does the amount seem significant? Then Audi Q7 is not for you.
Audi cars are one of the most desirable representatives of the secondary market. There are several reasons for this interest: the high durability of many models, pleasant finishes, good equipment and excellent technical data. But when choosing a used "car with rings", you should be careful.
First of all, low prices are often a harbinger of twisted mileage or hidden defects. Second, parts and repairs are often expensive. Even if nothing breaks, maintenance costs will be high. At the same time, with an increase in the Audi class, the cost of ownership increases like an avalanche.
If the Audi A3 is not yet so expensive to maintain, then the Audi A6 may be unbearable. It's all about the more complex suspension, electronics and densely filled engine compartment.
Both gasoline and diesel engines can generate unexpectedly high costs. Among gasoline units, a breakthrough occurred in 2007. Then 1.4, 1.8 and 2.0 TFSI got under the hood of Audi. At the same time, numerous troubles rained down: the timing drive failed, oil zhor appeared, pistons collapsed. The V6 went bad a little earlier, when the fast and durable 2.4 was replaced by the 2.4 FSI.
No less complicated story in the diesel branch. An example of this is the successful 1.9 TDI and the failed 2.5 V6 TDI (the latest versions of which, for example, BAU, have already been practically freed from the drawback). Then came the unsuccessful 2.0 TDI PD with pump injectors and the decent 3.0 TDI V6. The 2.0 TDI PD was later replaced by the improved 2.0 TDI CR with common rail injection.
Gasoline engines
1.6 8V - low maintenance
From a 1.6-liter gasoline aspirated, you should not expect good dynamics and efficiency. However, the Audi A3 with 1.6 8V is the cheapest Audi to maintain. Those who like dynamic driving should stay away from cars with such an engine.
This motor can be found under the hood of the Audi A3 (1st and 2nd generation) and A4 (B5 and B6). It was also widely used in other VW Group vehicles. Moderately decent rides only the first A3, which weighs a little over a ton. A4 B6 for 1.6 is too heavy. The disadvantages include fuel consumption. 9 liters per 100 km seem disproportionately large for mediocre dynamics.
However, in the era of complex motors, this is the only unit that guarantees low operating costs. Among the typical malfunctions, one can only note failing ignition coils and throttle contamination. Nothing expensive. Timing belt replacement? Installation gas equipment? It doesn’t get cheaper, especially when compared with engines with direct injection and a timing chain drive.
The engine uses an aluminum body and head. The crankshaft is supported by five bearings, and multi-point (distributed) injection is responsible for the fuel supply. The camshaft is located in the head of the block.
Advantages:
Simple construction;
Cheap repair;
It tolerates the introduction of HBO;
The low cost of the car.
Disadvantages:
Poor dynamics (overtaking is difficult, especially in the case of the A4);
Relatively high fuel consumption.
1.8 Turbo - powerful and reliable
The 1.8-liter turbocharged engine is still worthy of attention. It is durable and fairly cheap to repair. The possibility of tuning is also appreciated.
1.8 T provides decent performance and reasonable fuel consumption. This is one of the first turbo engines to be widely used. It can be found not only in Audi, but also in Volkswagen, Skoda and Seat. The engine was used even in industry.
The unit has a cast iron block, a forged steel crankshaft and an aluminum block head with 20 valves (3 intake and 2 exhaust per cylinder). A toothed belt is used to drive one camshaft, while the second shaft is connected to the first by a short chain. Turbine KKK without movable blades (invariable geometry), and fuel injection is distributed. The block in the "dry state" weighs about 150 kg.
It soon became clear that the 1.8 Turbo had a lot of potential. Serially, 240 hp was removed from it, and in the process of tuning it easily withstands boosting up to 300 hp. Of course, in the case of a tuned unit, vigilance should be increased, since it may already be hackneyed.
And yet, more often the turbo engine was not used for sports trips. Under normal conditions, a car with such an engine consumes from 9 to 14 liters per 100 km.
With age, a number of shortcomings were discovered (timing belt and thermostat), but their elimination does not require large expenditures.
Advantages:
Good compromise between performance and fuel consumption;
Availability and availability of spare parts;
Wide selection on the market.
Disadvantages:
Several unpleasant typical defects in older cars with high mileage (oil consumption and timing problems).
Application examples:
Audi A3 I (8L);
Audi TT I (8N);
Audi A4 B5, B6 and B7.
2.4 V6 - only until 2005
Despite the emergence of increasingly powerful inline turbo-fours, Audi fans still prefer naturally aspirated petrol V6s, especially in early versions. Of course, you should not count on low fuel consumption - at least 10 liters per 100 km. In the city you have to reckon with even 20 liters. But, the trip will seem pleasant.
Two generations of the 2.4-liter engine should be clearly distinguished. They have the same volume and dimensions, but in 2004 there was a modernization. Before the upgrade, the block was cast iron, and the head had 30 valves (5 per cylinder). After that, the block became aluminum, the number of valves decreased to 24, direct injection and a timing chain appeared.
The latest innovations have failed. Due to the direct injection system (FSI), carbon deposits accumulated on the valves after several tens of thousands of kilometers. There were problems with the timing chain tensioner and a small mesh filter in the lubrication system. Complete disregard for noise often resulted in chain jumps and serious damage. In 2008, Audi eliminated the vulnerability of the timing drive, but the engine could not withstand the pressure of 4-cylinder turbo engines.
Advantages:
Good elasticity;
High reliability (only before upgrade);
Versions with distributed injection easily tolerate the installation of LPG.
Disadvantages:
The limited meaning of installing HBO in an updated version of FSI;
Expensive timing failures (FSI);
Fairly high fuel consumption.
Application examples:
Audi A4 II (B6);
Audi A6 C5 and C6.
Diesel engines
1.9 TDI - durable and economical
This is the most recognizable diesel recent years. Even an older Audi with a 1.9 TDI is worth looking at - solid construction and inexpensive repairs.
1.9 TDI - the engine is a legend. Produced since 1991 and modernized many times. It has found application in many other VW Group vehicles.
The most reliable and cheapest in operation and repair is the 90-horsepower version with a distribution-type injection pump. The engine has a simple design, a turbine of constant geometry and a single-mass flywheel.
Yes, minor problems sometimes happen. For example, with an exhaust gas recirculation valve, an air mass meter and a fuel pump. But for the most part, malfunctions are not caused by design flaws or poor quality, but by a decent age and high mileage.
The younger and more powerful versions of the 1.9 TDI have more solutions that can create problems. We are talking about a variable geometry turbine, a dual-mass flywheel, pump injectors and a DPF. However, even these versions against the background of diesel engines appear in a more favorable light.
The exception is the 2006-2008 BXE version, which, for example, fell under the hood of the second generation Audi A3. There are many cases of turning the liners after 120-150 thousand km.
Advantages:
Simple construction;
Good endurance;
Low fuel consumption.
Disadvantages:
Many hackneyed copies (the engine was installed until 2009, and since 2004 it has been gradually replaced by a 2-liter turbodiesel);
Low work culture: noise and vibration, especially after starting a cold engine.
Application examples:
Audi A3 I (8L) and II (8P);
Audi A4 B6 and B7;
Audi A6 C4 and C5.
2.0 TDI CR - all is well at last
A 2-liter diesel engine is the main unit for most Audi models. Since 2007, he began to use the common rail injection system.
The design flaws of the 2.0 TDI with unit injectors prompted Volkswagen engineers to thoroughly modernize it. Changing the way you eat is the most important innovation. The pistons were also updated, problems with the oil pump drive were eliminated, a new block head and camshafts were installed. As a result, the durability of the engine was significantly improved, but there were also disadvantages.
When buying an Audi with a 2.0 TDI engine, you should check the history of the car. Often, these were cheap and economical versions purchased for commercial or corporate garages. They have huge mileage and have not always been well maintained.
Typical malfunctions affect the dual-mass flywheel and turbocharger. Piezoelectric injectors fail here no more often than competitors. Luckily, they are repairable. As part of the service campaign, the manufacturer changed high-pressure lines.
Advantages:
Good performance with acceptable fuel consumption;
Good durability (especially compared to 2.0 TDI PD);
Great variety of versions.
Disadvantages:
Expensive maintenance (complex design and expensive spare parts);
Significant mileage of many copies, despite the relatively young age.
Application examples:
Audi A4 III (B8);
Audi A6 III (C6).
3.0 TDI - for demanding
High performance and dynamics are not the only advantages of the 3.0 TDI. Therefore, many choose it with pleasure, even despite the rather high maintenance costs.
The 3.0-litre turbodiesel was intended to correct the bad reputation of Audi's diesel V6s, which had been tarnished by the 2.5 TDI V6. The 3.0 TDI earned respect not only for its performance, but also for its durability. The block, cylinder head and crank mechanism turned out to be very strong. For each cylinder there are 4 valves and one piezoelectric injector.
The problems concern mainly the equipment. Most often they encounter a timing drive, the cost of replacing which is very expensive. Until 2011, 4 chains were used, and after - two. The drive chain is located on the gearbox side. To replace it, you have to remove the engine.
Not spared from the shortcomings of the damper in the intake manifold (repair kits are available) and DPF. The engine is constantly being improved, and in later versions, malfunctions are much less common.
Advantages:
High culture of work;
Good performance;
Low fuel consumption;
Good service life of many engine parts.
Disadvantages:
Expensive to troubleshoot timing, intake manifold and DPF;
Many copies on the market have high mileage and questionable technical condition.
Application examples:
Audi A5 I (8T/8F);
Audi Q7 I (4L);
Audi A8 II (D3).
Risky choice!
There are engines in the Audi range that are great in theory but painfully disappointing in practice. In particular, mention should be made of the first generation 1.4TFSI with a problematic timing chain drive. Currently, a more reliable version with a timing belt drive is used.
The 1.8 and 2.0 TFSI engines with the code designation "EA888" tempt with high performance. However, they suffer from high engine oil consumption. There are problems with the turbine, camshafts and electronics.
There are black sheep among diesel units. For example, a 1.4 TDI with pump injectors was installed in the Audi A2. The problem is the appearance of crankshaft play, the elimination of which is not economically feasible. The 2.0 TDI PD is known for its cracking head and poor equipment durability. 2.5 TDI V6 is tormented by numerous blunders with the timing, as well as with the lubrication and power system.
Conclusion
Once upon a time, buying an Audi was easier - the engines guaranteed quiet operation. Currently, you need to pay attention to the version. Along with really successful engines, those for which the designers should be ashamed were also used. At the same time, even a fairly reliable modern engine will be expensive to maintain and maintain.
