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Audi A6 C5: Common Problems

If you own or are thinking about owning an Audi A6 C5, keep reading to learn about some common problems other owners have encountered.

By Charlie Gaston - April 4, 2016

This article applies to the Audi A6 C5 (1998-2004).

The Audi A6 C5 is a beautifully engineered car that boasts a competitive roster of features, including, but not limited to, a highly rated BOSE audio system, heated seats, power windows and more. Thanks to a sophisticated suspension system, the A6 C5 delivers incredible performance on the road. This is not to say owners of the A6 C5 have not reported experiencing some problems, both inside the vehicle and under the hood. Let's take a look at some of the commonly reported problems and how you can successfully deal with your Audi A6 C5 as it gains more mileage on the odometer.

Audi A6 C5

Easy-to-Resolve DIY Repairs

The biggest determinant of whether you're Audi will experience a high number of problems is how you properly maintain it. Having said that, if you do experience problems, they are likely to be small, particularly within the first 50,000 miles of owning your car. For example, you might experience a bad window switch or some other electrical-related problem. Wear and tear could also begin to show up on your tie rod ends, CV boot and/or water pump bearing.

Figure 1. Have you checked the condition of your CV boot lately?

Moderate Repairs

Problems related to your timing belt could creep up as your Audi ages (75,000 miles or more), resulting in the need for a full repair. Unless you are skilled in repairing or replacing a faulty timing belt, it's highly recommended that you leave this repair to the professionals. In addition, have your automotive service provider check your water pump, idlers, and belt tensioner, as all of these need to be checked (and/or replaced at around 75,000 miles).

Figure 2. Check all of your belts for wear and tear, or slippage.

Professional Repairs

If the catalytic converter in your Audi goes, as it has for a number of other A6 C5 owners, you will need to have the component serviced by a professional mechanic; obtaining the correct aftermarket part on your own could prove difficult. Signs of a bad catalytic converter include a reduction in power and the smell of raw fuel.

Figure 3. This is a generic catalytic converter.

Common Questions

When it comes to DIY repair work, are there any online resources I should know about?

Many Audi owners who prefer to handle easy-to-moderate repairs and routine maintenance work on their own will often look to Audi forum threads for suggestions, tips and instructional guides. The information is free, and there are other do-it-yourselfers who can attest to the ease or difficulty of a project.

When is my Audi most likely to begin to show signs of wear and tear?

Generally speaking, you shouldn't experience too many problems in the first 50,000 miles of driving your car. However, after that point, small repairs could creep up here and there. The best way to offset the cost of many of these repairs is to purchase an extended warranty or service contract; be sure to read the fine print first, however.

When should I run my error codes?

Whenever you notice a problem, it is a good idea to run your error codes. For example, if you have a bad 02 sensor or dirty throttle body, you will want to run your codes to determine the issue right away (and decide if you can complete the repair on your own). If you do not already own one, it's highly recommended that you purchase a VAG-Com cable and software.

Common Issues

Aftermarket Wiring

While you might be tempted to perform an advanced audio install in your Audi, it's highly recommended that you don't (unless you are properly and adequately skilled in wiring). A number of Audi owners have experienced problems with wiring because they were NOT skilled enough in this area to do an excellent (or passable) job. Remember, the Audi is a very sophisticated machine that often requires professional knowledge for some repairs and aftermarket modifications.

Cutting Corners on Maintenance and Repairs

To reach 100,000 miles or more on the odometer, be sure to properly care for your Audi. That includes having all repairs and maintenance work performed by a certified Audi dealer or licensed mechanic (unless you are trained in repairing cars). The Audi A6 C5 is one vehicle on which you won't want to cut corners when it comes to repairs and maintenance work.

Noise in the 2.7L Turbo Engine

Noise in the front of the engine could be the result of a belt tensioner bearing or belt issue. A stuck fan clutch or faulty alternator could also be the culprit. The issue will most likely not be related to your wheels or transmission, if the noise is present while your car is parked. Check the water pump as well.

Torque Converter Problem

The problem is most likely related to a poor electrical connection or blocked oil passage. You are most likely dealing with an open or short circuit condition that will require professional assistance.

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