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Home » Audi A6 Allroad [C5](1999-2005) Problems, Review, Faults and Information

Audi A6 Allroad [C5](1999-2005) Problems, Review, Faults and Information

Audi A6 Allroad C5 was presented in 1999. It is the first generation of the model and actually the manufacturer simply called it Audi Allroad, but since it is based on Audi A6 Avant C5, it can also be called Audi A6 Allroad. In 2002 it underwent a restyling that brought changes to the design and some modernizations on a technical level and in the interior. The car was produced until 2005, and in 2006 it was replaced by the next generation Audi A6 Allroad C6. Let’s see the review on the Audi A6 Allroad C5 with the most important information, faults and common problems.

Table of Contents

Review of the Audi A6 Allroad C5 with all the information, defects, issues, faults, weaknesses, problems and maintenance costs.


Impressions, Interior and Comfort

Audi has set itself the goal of creating a universal car that can fit in any situation. As a result, the Audi A6 Allroad C5 was obtained and it can be said that the goal was achieved. At the same time, Volvo and Subaru also presented their station wagons with off-road potential. It was a trend of the period, but we can immediately anticipate that the Audi A6 Allroad C5 wins against its competitors.

It’s important to understand that the Audi A6 Allroad C5 is not a true off-roader, so don’t think it has extraordinary off-road capabilities. The good off-road qualities are given by the continuous four-wheel drive and the air suspension with ground clearance adjustment.

Platform and Body

From the point of view of the platform there is nothing new, it is the same platform that we have seen on the Audi A6 C5. The engine is installed longitudinally, the drive is Quattro all-wheel drive. It is not possible to have only front-wheel drive. Quattro is a very good permanent all-wheel drive system with a Torsen differential.

The suspension of the Audi A6 Allroad C5 is similar to that of the regular Audi A6 C5. They are multilink suspensions with aluminum arms. Instead of the classic shock absorbers, the Audi A6 Allroad has air springs.

The body design of the Audi A6 Allroad C5 is the same as the normal A6 Avant, but it is more brutal and severe due to the opaque protective plastics, particularly noticeable on the bumpers and wheel arch widenings.

Review of the Audi Allroad A6 C5 with all the information, defects, issues, faults, weaknesses, problems and maintenance costs.

Aesthetically, the car is attractive, both before and after the restyling, especially in the more equipped versions.

The first generation Audi Allroad is available in only one body version – raised station wagon (similar to Audi A6 Avant). If you want a more conventional car, you can opt for a classic Audi A6 C5 which is available as both a sedan and an estate.

Comfort and Practicality

From the point of view of space, the situation is quite good. On the front seats anyone will be able to position themselves comfortably, even the rear passengers will be comfortable if they are not particularly tall. For long journeys, it’s best for two to sit in the back, three passengers on the rear sofa will have a little lack of space.

The trunk/boot has a volume of 455 liters and by completely folding down the rear sofa, the volume can reach 1590 litres.

In addition to having an adjustable height, thanks to the Audi A6 Allroad air suspension it also has excellent ride comfort and very good stability on the road. Even on longer journeys you don’t get very tired.

Interior and Equipment

in this photo you can see the interior compartment of the Audi A6 Allroad C5 with the steering wheel, the stereo radio, the seats and the dashboard central panel cockpit

The interiors are luxurious. In the end it’s the same interior as the Audi A6 C5 which is a premium German car. The materials are of high quality, the assembly is good, the central panel is full of buttons with which you can control the large number of options.

The materials hold up quite a long time if treated properly and even after many kilometers they are both tactile and visually pleasing. If you find an Audi A6 Allroad C5 with a wrecked interior (broken seat covers and bad steering wheel) then most likely the mileage is close to 300,000 km (185 k miles). You have to pay attention to these details as it is very easy to lower the mileage on this car.

However, all this does not apply to the buttons, these are made of white plastic, so even the slightest deterioration of the fragile paint is highly visible. Obviously nowadays Audi A6 Allroad C5s are already old, with a lot of miles and because of this in most cases the paintwork of the buttons is in a bad state and also the upholstery of the seats and the steering wheel are not in very good condition.

The good part is that all traces of wear and tear present in the cabin can be eliminated if desired. Some pieces can be replaced, others can be repainted or restored.

The soundproofing is very good and the interior remains silent in any situation.

Given the large amount of electronics included in the Audi A6 Allroad C5, the possibility has appeared of offering many systems intended to increase comfort and safety. The trims are generally very good. In general it is almost impossible to find an Audi A6 Allroad C5 in poor trim. Generally there is everything needed for comfortable daily use.

The basic multimedia system is good, but offers few features and has acceptable audio quality. Optionally, you can have a more sophisticated system, with a display and more features. The Bose sound system will also offer very good sound quality.


In the EuroNCAP safety test, the Audi A6 Allroad C5 got 4 out of 5 stars. Crash safety is quite good, but to decrease the risk you need good tyres. Tires are almost the most important thing for safety on the road.

Reliability and Issues

Gearbox and Transmission

The Audi A6 C5 Allroad can have a manual gearbox or a classic automatic gearbox.

Manual transmission

The manual gearbox has no particular problems and is quite reliable. Up to 200,000 km (125 k miles) it shouldn’t give any problems. Beyond this mileage there may be difficulties in shifting gears.

The dual mass flywheel is very expensive and does not last long on the Audi A6 Allroad C5 with powerful engines or which undergo aggressive use. In addition to the high cost of the flywheel, the cost of the work must be added. A non-original flywheel from an alternative manufacturer can also be fitted to save money. A good alternative flywheel will cost about half.

It is also important to check if there are no oil leaks from the gearbox, check the oil level and its quality.

ZF 5HP automatic gearbox

The automatic gearbox can be considered quite good. It is a ZF 5HP19FL 5-speed automatic transmission. From 2003, the 4.2 l petrol engines were fitted with the ZF 5HP24FL reinforced gearbox.

The weakest version of the automatic transmission always works at the maximum limit. This gearbox is able to withstand about 350 – 400 Nm of torque and is always under stress due to the great power of the engines. It makes the situation even worse if the engine is tuned and its power increases. The reinforced version is more resistant and does not suffer as much. However, this too is not immortal.

Be that as it may, the ZF 5HP gearbox as well as being quite fast for its period, is also very reliable in general. Of course it has some weaknesses. He doesn’t like aggressive starts, skids and shifting the selector between D and R while the car is not yet stationary.

The ZF 5HP automatic gearbox as well as being quite fast for its period, is also very reliable in general. Of course it has some weaknesses. He doesn’t like aggressive starts, skids and shifting the selector between D and R while the car is not yet stationary.

After 200,000 km (125 k miles), the main problems are the failure of the oil pump and the premature wear of the torque converter and its lock-up clutch. Generally, after this mileage, you may start to feel knocking during downshifts. These are often caused by worn solenoids and various sensors.

The valves in the hydraulic block (Valve Body) can wear out over time and this will cause rough gearbox operation. There can be also problems with the drums.

Generally automatic gearboxes shouldn’t give problems before 200,000 km (125 k miles). If treated with care and serviced correctly, it can even go beyond 300 – 350,000 km (185 – 220 k miles).

When the time comes to repair the automatic transmission, the price usually is very high. However, you can save money by using used or regenerated components and in this way the price is halved. If you choose to save money, the vitality of the gearbox will also suffer and it will live for fewer miles.

Drivetrain and Transmission System

Before buying an Audi A6 Allroad C5 it is advisable to check the rear differential and see if it is not leaking oil. Quattro all-wheel drive system is one of the most reliable and hardy, but even it cannot live on insufficient or bad quality oil. If during a check you observe play of some elements and if the protections of the axle shafts are damaged, quite probably large investments will have to be made in a short time.

With the more powerful engines there are cases of wear of the cardan shaft (drive shaft) and the rear reduction gearbox. The constant velocity joints will also need to be changed after 200 – 250,000 km (125 – 155 k miles).

Those who love skidding on asphalt will have more serious and more frequent problems.

Suspensions, Steering and Brakes

Audi A6 Allroad C5 is equipped with air suspension. These are reliable and long-lived, generally easily exceeding 200,000 km (125 k miles). Unfortunately sooner or later there will be money to invest and the costs will not be low. A new air spring is quite expensive. Even if the air compressor fails, a lot of money will have to be spent on repair or replacement. Obviously cars that have been off-roading a lot will have more worn suspension.

Due to the large costs, some owners replace the air suspension with simple suspension (shock absorbers and springs).

However, the air suspension is not the only concern, the Audi A6 Allroad C5 has aluminum multilink suspension. If you make frequent trips on off-road, you may need to replace the expensive aluminum links as often as every 20,000 km (10 – 15 k miles). Obviously, they live much longer on roads in good condition, but still not indefinitely.

A whole kit of original spare parts for the front axle is generally expensive, with non-original spare parts it costs about half. The mechanics recommend replacing the whole kit of elements, since they generally give out at about the same mileage and it is not advisable to do the work for each element separately.

All this concerns the front suspension more, the rear ones are more reliable and resistant.

If you decide to buy a used Audi A6 Allroad C5, it will be good to check the suspension carefully and look at it from underneath. The car may have been used off-road and therefore have traces of dirt or other damage. Better to avoid such a car, or at least ask for a good discount.

Steering system

The steering system feels relatively sensitive under stress. The steering rack may begin to leak and the power steering pump may fail. In light conditions, they live even more than 200 thousand km (125 k miles), but under stress they live less. Better to avoid turning the steering wheel when the car is stationary and cold. In general, it’s best to avoid putting too much effort on the steering system.

Brakes system

The brakes are efficient and reliable. Some owners upgrade them even further by fitting those of the heavier Volkswagen Touraeg SUV. The ABS module is relatively fragile. It can stop working due to problems with the power supply or due to sensor errors (even if the latter are working properly).

The ABS control unit of the Allroad is different from that of the simple Audi A6 C5. Fitting the wrong ECU will cause problems with the ESP.

It is also important to check the status of the brake system channels. These tend to wear out over time.

Electronics and Electrical System

On the Audi A6 Allroad C5 there can of course also be problems with the electronics. In general they are about the same as the regular Audi A6 C5. Given the age of the car, there may be many problems, but they are generally minor and easily solved.

It will be necessary to replace lambda sensors relatively often on petrol engines. They generally don’t last more than 100,000 km (60 k miles) and any overheating could ruin them. If this happens, there will be less power and more consumption.

Other famous problems are those with malfunctioning electric windows, burnt out light bulbs, trip computer and climate control displays that stop working.

The fuel pump generally does not live long and on the Audi A6 Allroad C5 on the used cars it is almost always already replaced. The fuel level sensor can also give problems. The repair work is quite complex and not all mechanics can do it well. To definitively solve the problem, you need to go to a specialized workshop.

Body position sensors can be considered a weak point. Not only the functioning of the headlights depends on these, but also that of the air suspension. Parking sensors can also stop working.

The likelihood of problems appearing is higher on older cars.

Due to the complicated electronics, current leaks may appear on some cars. These power leaks can drain the battery even after 2 – 3 days (in the worst cases even overnight).


Thanks to the great paint quality and good corrosion protection, the Audi A6 Allroad C5s are still beautiful and visually pleasing. If large traces of rust are found, the car most likely suffered accidents and then was badly repaired.

When buying an Audi A6 Allroad C5, it would be good to check the condition of the trunk and its floor. These cars are sometimes used to carry heavy weights and this is not a good thing. If the trunk has serious signs of wear, it would be good to also check the welds on the chassis which can give way in certain situations of excessive effort.

Quite often the locks on the doors are ruined. The first symptoms of a breakdown will be central locking malfunctions and the inability to open the door from the outside.

There are cases of breakage of the wiper mechanism (generally due to oxidation). The electric motor is quite powerful and could burn if it jams.

The headlights lose efficiency over time (the reflecting element burns out). Some workshops are able to repair them, or new elements can be fitted at a higher price.

Engines and their Problems

Diesel engines list :

Version Engine Power Top Speed Acceleration Fuel Consumption
2.5 TDI quattro 2.5 l EA330 (BFC, BCZ, BDG) 163 hp 203 km/h or 126 mph 10.4 s 8,7 l/100 km

US: 27 mpg

UK: 32,5 mpg

2.5 TDI quattro 2.5 l EA330 (AKE, BDH, BAU) 180 hp 207 km/h or 128 mph 9.5 s 8,7 l/100 km

US: 27 mpg

UK: 32,5 mpg

Petrol/Gasoline engines list :

Version Engine Power Top Speed Acceleration Fuel Consumption
2.7 V6 30v biturbo quattro 2.7 l EA835 (ARE) 250 hp 236 km/h or 146 mph 7.4 s 12,8 l/100 km

US: 18,3 mpg

UK: 22,1 mpg

4.2 V8 40v quattro 4.2 l EA824 (ARS, ASG, BAS) 300 hp 240 km/h or 149 mph 7.2 s 13,7 l/100 km

US: 17,1 mpg

UK: 20,6 mpg

problems and issues with petrol, gasoline, LPG, CNG, methane and diesel engines mounted on Audi Allroad A6 C5


The list of engines fitted to the Audi A6 Allroad C5 is smaller than that of the normal Audi A6 C5.

Diesel Engines

The only diesel engine fitted to the Audi Allroad is the 2.5 l TDI in two power versions. It is an aggregate that corresponds to the character of the Audi A6 Allroad C5, it has good torque while maintaining relatively low fuel consumption. Let’s see it in more detail.

2.5 l TDI V6 EA330 diesel Engines

The 2.5 l TDI V6 diesels are from the EA330 family. These are presented here in two generations: generation A (engine code starts with A, for example AKE) and generation B (engine code starts with B, for example BFC, BCZ, BDG, BDH, BAU).

These are units with a cast iron cylinder block, two aluminum cylinder heads and a timing belt. Each of the cylinder heads has two camshafts, in total there are 24 valves and there are hydraulic compensators. The injection is direct with a Bosch VP44 high pressure pump.

EA330 generation A 2.5 l TDI engines may have problems with the camshafts (cams and rocker arms wear out too quickly). After 220 – 250,000 km (135 – 155 k miles) the high pressure pump may fail (even earlier if low quality diesel is used). These two weak points are the most famous and expensive ones to repair.

Among the less serious problems we have the crankcase ventilation system filter which becomes clogged and requires periodic cleaning. The flowmeter is not too long-lived. At high mileage, oil leaks may appear at the point of contact between the block and the sump or from under the valve cover.

Around 150 – 200 thousand km (95 – 125 k miles), the turbine geometry adjustment system can get dirty and block.

In 2003, generation B appeared and brought about important changes. First of all, the problematic timing mechanism has been updated: here the cam of the camshaft presses on a roller bearing. This choice has made it possible to increase the life of the rocker arms.

The BFC engine, while theoretically part of generation B, still has the old type of distribution, so in fact it can be seen as a generation A engine.

Otherwise the same weaknesses remained. However, there may be some cases when the modernized camshafts burst (even at mileage of 150 – 250 thousand km or 95 – 155 k miles).

All 2.5 l TDI engines love high-quality oil and its frequent replacement. Bad oil contributes to the wear of the hydraulic compensators and worsens the operating conditions of the camshafts.

Despite all the weaknesses, it must be said that engines treated well have a decent life. Generation A aggregates should live at least 250,000 km (155 k miles) without fatal defects, while those of generation B can even exceed 320,000 km (200 k miles) without major failures.

Petrol/Gasoline Engines

There are two petrol engines: the 2.7 l bi-turbo V6 and the 4.2 l V8.

2.7 l V6 30v Turbo EA835 Engine

The 2.7 l petrol engine is very good in terms of power. It’s a good alternative to diesel, but it’s not perfect. In addition to having two turbines, the engine also has a very complex intake system. The greater complexity requires more attention from the owner. First of all, the cooling system must always be kept in good condition as these are very hot engines that can easily overheat. The coolant pump and thermostat do not demonstrate great reliability and durability.

Oil leaks are encountered quite often. Impermeabilityleaks that cause unnecessary air to penetrate are not uncommon.

Turbines don’t always have a long life. On average, they live around 150,000 km (95 k miles), but there are also cases where they “die” at around 100,000 km (60 k miles). If well treated they can live even more than 200,000 km (125 k miles). The probability that the oil channels going to the turbines become clogged is relatively high and this obviously causes their accelerated wear. This can happen due to poor maintenance or the wrong style of use.

Sometimes there may be irregularities in the operation of the turbines. To solve them, it is usually sufficient to change all the air ducts and the intercooler. Even the intake in bad condition does not extend the life of these aggregates, so you have to keep an eye on it. Another bad part is that the turbines are hidden at the bottom and therefore difficult to control.

Here too it is advisable to replace the timing belt every 60,000 km (35 k miles) to prevent it from breaking which damages the valves. The chain, on the other hand, should be changed every 120,000 km (75 k miles). A lot of attention is also needed for the ignition system and in particular for the not too long-lived coils.

The crankcase ventilation system on 2.7 l engines can start to give problems after 10 years of life. Due to its wear there will be increased oil consumption, detonation and problems with the formation of the mixture. If you don’t take action in time, all this could lead to bad consequences.

Engine reliability is good, but not great. Serious problems can usually appear after 200,000 km (125 k miles).

4.2 l V8 40v EA824 Engines

The largest and most powerful engines mounted on the Audi A6 Allroad C5 are the 4.2 l V8s of the EA824 family, but in reality the cars fitted with it, due to their great weight, are not much faster than those with the 2.7 l petrol engine.

These are quite reliable engines (as much as possible on a sports car with impressive powers). Despite the aluminum cylinder block, destruction of the cylinder walls is rarely encountered. However, this is very likely if poor quality oil is used, if the oil is rarely changed or if the engine overheats.

In general, the 4.2 l V8 engine (like the 2.7 l turbo) is at risk of overheating and therefore you need to pay close attention to the temperature, the various sensors and the cooling system in general.

The distribution has both the belt and chains at the same time. The most frequent and widespread problem is the failure of the chain tensioners. The belt must be monitored constantly and replaced in time, if it breaks the valves will be damaged.

Oil leaks are also encountered on this engine (even greater than on smaller engines). It usually occurs at the point of contact between the engine and gearbox.

The main advantage of this great engine is simplicity. Given the great age of the cars, the large 4.2 l could be cheaper to maintain than the complex 2.7 l. If large fuel consumption scares you, you can opt for a gas system. This engine takes it well.

Conclusions and Advice & Tips for buying used

Audi A6 Allroad C5 is a very good car. It is truly universal and very practical. It is spacious, comfortable, luxurious and also has good off-road capability. However, you must be aware that the car is now old and the most serious problems are starting to appear. Among the most serious age-related problems are those of electronics and suspension. Large mileages on the other hand will lead to problems with engines and gearboxes.

We strongly recommend that you also read the article on the Audi A6 C5 in which you can find more information on features and problems.

We also advise not to waste the last money on the purchase of a used Audi A6 Allroad C5. Even if the engine and gearbox are in perfect condition, it is better to keep some money in reserve for any unforeseen repairs.

The main competitors of the Audi A6 Allroad C5 are: Volvo XC70, Subaru Outback and other cars of this type. Furthermore, the competitors of the normal Audi A6 C5 can also be evaluated: Mercedes-Benz E-Class W210, BMW 5 Series E39, Volvo S80, Volkswagen Passat, Lexus GS and others.

Given its good off-road qualities, it can also be compared with some SUVs: Mercedes-Benz ML W163, Volkswagen Touareg, Volvo XC90, BMW X5, Land Rover Discovery III.

The most important thing is to find a car in good general condition.

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