I will start with the D2 A8 97-03
MAINTENACE:

1. For the 4.2L and 3.7L engines you will need to have the spark plugs changed every 60k along with the engine air filter, before you change the plugs you want to seafoam the intake system. How you seafoam the intake is find a vacuum line while the engine is running and slowly pour the can of seafoam into the vac line until the can is empty. This will also create a serious amount of toxic smoke from the exhaust so only do this in a well ventilated area. After the seafoam treatment is done, then change the plugs, the seafoam can foul up the plugs.

2. At 80k you will want to get the transmission fluid changed, along with the timing belt/water pump, thermostat, serpintine belt/s and complete fault memory checked and erased.

3. The services between 80k and 160k should only be minor maintance, just repeat the #1 step at 140k and repeat the #2 step at 160k.
If you follow these steps your D2 A8 should run like a champ for years to come.

4. Always change your brake fluid at least every 100k, earlier if at all possible.

PROBLEMS:

1. The 3.7L engine as well as the 4.2L engines will have oil leaks from the valve cover gaskets anytime after the 50K mark. They usually only last about another 50k after you replace the gaskets so if you ever sense an oil burning smell, thats whats happening.

2. A unique issue for the 3.7L is faulty crank sensors, when these go you will have a crank no start concern.

3. Unfortunately both the 3.7 and 4.2L D2 A8 have transmission problems. Most commonly with the reverse gear which will prevent you from backing up. The only way to combat the effects of a failing transmission is to make sure it doesn't leak and keep the fluid level correct and clean by changing it every 80k.

Now on to the more complicated D3 A8.

MAINTENACE:

1. Check the brakes every 20k with a flashlight, depending on where you are in the country these can wear at different rates, take special attention to the rear brake pads and change them when they reach below 5mm pad thickness. The inside pads wear at a faster rate than the outer pads, so if the outside pads have around 5mm chances are the inner pad is almost metal to metal.

2. The same applies to the D3 as it does to the D2 at the 60k mark, seafoam treatment and spark plugs should be changed, as well as the air filter.

3. The 80k mark requires the changing the timing belt/water pump, tensioner, idler pulleys, thermostat, serpintine belt, transmission fluid and brake fluid. 07+ models use a timing chain which doesn't require service.

4. Always pay attention to the ride height of the vehicle, if one corner of the vehicle seems lower than other corners of the car the air bag may be leaking. Get it fixed ASAP, if you let it go the air compressor constantly has to work to keep the car at constant ride height which will burn out the compressor.

PROBLEMS:

1. At the 50k mark you may notice a clunking while turning, this is due to worn out upper control arm bushings. The reason for this is the A8 uses a much larger control arm but uses the same size bushing as the A4. Audi may have been trying to save money but it is a design flaw in my opinion.

2. If your MMI screen ever gets stuck behind the dash, the motor is sticking and needs to be replaced.

3. The 04 model has design issues with the trunk lid. If you ever experience a problem with the trunk lid opening or closing you either have a broken or outdated trunk lift motor, and or faulty trunk hinges. There is a TSB at audi for replacing these pieces with updated ones.

4. The 04 model also has another design flaw when changing the oil, there is a metal coolant pipe that runs directly over the oil filter. In order to get the filter out the pipe has to be replaced. The dealer of course doesn't want to do this so techs generally bend the pipe with a pry bar to get the filter out. IF the tech bends it to far it could cause a coolant leak that sometimes requires removing the engine.

5. 04+ A8's may need updating of the MMI system due to common glitches. There are too many glitches for me to list, but if you find that there is something wrong or just plain annoying with your MMI's functionality, there is probably a re-flash for it.

All parts and maintance items can most likely be purchased at www.ecstuning.com www.blauparts.com, www.germanpartsonline.com and www.purems.com. If you wish to get your own diagnostic equipment visit www.ross-tech.com to download the VAG COM software, you just need to buy the cable. You also need this tool to change the rear brakes on a D3 A8.

Any other questions PM me. Happy motoring

 

Thanks for posting

 

thanks that was really helpful... i have a '00 d2 that's right around 61k miles.

 

Thank you for the post. I have a 2005 A8L and would like to see a some info for that year model. My car now has over 80K miles and has always been to the dealer for service.

 

Can someone please describe the reason and benefits of the sea-foam application prior to replacing the spark plugs.

I have checked the coil packs and found that several of the spark plug boots were old and split on the plug ends. I think the coil packs are original and running OK. Just voltage leakage due to the sp boots. I can not find an reasonably prices sp boots. Any source suggestions?

I have never owned an auto or Audi that recommends a sea-form treatment. Any sources suggestions for this as well?

Thanks for any help.
Dennis

 

the seafoam deal is just to burn out any carbon residue in the cylinders an don injectors. pretty much like performing an injector flush but mainly its to clean out cylinders from carbon buildup

 

Is the air suspension standard on all of the 05-06 A8's (A8 or A8L)?

 

I have a 2005 A8L with 53k miles on it. Recently I've noticed a low level vibration, which becomes very evident around 20mph, when braking. I had it checked during my last service and the dealer said it tires were out of round which didn't make sense. I took the car to an independent repair shop and they could not determine the cause of the vibration. The vibration is consistent and doesn't change when turning or in different gears. There are no oil leaks from the CV boots or other obvious signs of trouble. Any suggestions before I take it to another dealer?

Thanks,

Mrhnic

 

The saying "the tires are out of round" stands for a seperated belt inside the tire, which will cause vibration. The dealer had it correct.