Audi A6 C6: General Information and Recommended Maintenance Schedule
Drivers of the Audi A6 C6 have reported a few common problems. Between the forums and the factory recommended service, here's a brief rundown what they are and how to avoid them.
This article applies to the Audi A6 C6 (2004-2011).
The Audi A6 C6 comes with a reputation for performance and luxury, but there are some common problems that have cropped up as these cars age. Thankfully, the factory has come up with solutions to many issues that will be fixed under warranty, and the Audi owner community online has come up with ways to avoid many of them all together. With years of continued proper maintenance and on-going care behind the wheel, great on-road performance, reliability and luxury are exactly what drivers can expect. Let's go over a few common problems and how they can be fixed or prevented with a little mechanical skill (or at least a few service appointments).
Timing Chain Tensioners
The A6 is available with a variety of engine options, but both the V6 and V8 motors employ timing chains mounted at the rear of the motor that are very hard to get to. This becomes an issue as the cars get more mileage on them and the chain tensioners begin to wear out. If you fail to catch the increase in noise that signals the start of one going bad, you can quickly end up with a repair that involves the entire motor being rebuilt. Even if you do catch it in time, the motor must be removed to change the chain and tensioners.
Multitronic CVT Failure
Another known issue with non-Quattro models is with the continuously variable Multitronic transmission (CVT). If the PRNDS indicator is all lit up (as in the below picture), that means a fault in the transmission, which may render the car undriveable. Sometimes it is just a problem with the computer controlling the transmission, and turning the key off and on a few times will clear it, but many times it is an internal issue that requires a long stay at a garage for a rebuild or a replacement transmission. The CVT was only used in front wheel drive versions of the A6, so buying a Quattro equipped model is one easy way to avoid it.
If your window regulator starts to act up (e.g., fails to raise or lower the window, or does it very slowly), we highly recommended starting with the basics first. Spray a liberal amount of WD-40 on the channels the window slides in, and a little in the switch itself. Often times, though, the damage is internal and the inside door panel has to be removed to fix it. Audi uses a simple cable system, and if you are handy, as well as comfortable taking the door panel off, it can be fixed in your driveway in less than an hour.
Windshield Washer Sensor
If you've filled up your windshield washer reservoir with Rain-X washer fluid, then you could see some issues with your sensor. Problems occur as Rain-X coats the sensors and throws off your true reading. If you experience a 'low fluid' warning light, even with when full, you should drain your reservoir, flush it with clean water, and fill it with a different brand. Forum members recommend using your original equipment manufacturer (OEM) washer fluid or a brand such as Prestone.
While categorized here as a minor problem, some of these can still be major headaches. As is the case with all direct injected motors, the Audi A6 does have an issue with carbon buildup on the intake valves, which can cause a rough idle and slight decrees in performance. Some owners have reported higher oil consumption than they are comfortable with, though Audi says a quart every 1,000 miles is acceptable. The ignition coil packs do sometimes crack, leading to a misfire, but they can be replaced at a cost of just $200, including parts and labor. Check the links at the bottom of the article for more in-depth, online discussions of these and other A6 issues.
Replace your engine oil and filter about every 5,000 miles, or when the car's computer tells you to, and rotate the tires at the same time. It is very important for the health of the Quattro system that the tires wear evenly. If the vehicle computer does not indicate an oil change, you should still change it once a year no matter how many miles you drive.
At the 15,000-mile mark, a more involved service is called for. This includes replacing the fuel filter, engine air filter, and cabin air filter, inspecting many of the systems under the car and in the engine bay, and lubricating things like door hinges, linkages, and cables. The brakes fluid should be flushed and filled every two years as well, no matter the mileage.
At 35,000 miles, the transmission fluid should be changed, especially in the Multitronic CVT transmission, as well as the power steering fluid. This is also the recommended replacement interval for the spark plugs on some of the engines, but its a good time to do it no matter which version you have.
You can see the full service schedule for the 2011 model year (the last of the A6 C6 models) on the Audi USA web site in PDF form, and save it for future use by clicking here: 2011 Scheduled Maintenance Intervals
How many miles can I expect to reach with the A6 C6?
That depends, but generally speaking, it's reasonable to expect to reach (and surpass) the 150,000-mile mark. Keep in mind, though, you might need to have a few repairs made to you car in order to go beyond this mark. The Audi A6 is a finely engineered German sports sedan, but it is also a complex state of the art machine, so as they get older, some of the more advanced features may not seem all that advanced, and may be hard to fix, like the Multi-Media Interface (MMI). The basic mechanical parts should last well into 200,000 miles with proper maintenance.
Why won't my radio antenna work properly?
Your antenna amplifier could be faulty. Have it replaced. (This is a repair that may be covered under warranty.)