I have a '99 A6 Avant with about 130k. When I bought it about 2 1/2 years ago I noticed that it was very slowly loosing coolant, maybe a pint a month and you could smell the coolant burning. I tried to see where it was coming from w/o success. It has gotten progressively worse over the past 6 months. I took off the bottom engine cover to see if I could see where the leak was coming from and it is in the front of the engine. The leak is strange in that it is intermittent. It will leak sometimes and then not leak. We put the car up on a lift and my mechanic (not Audi) did a pressure test and we could not get it to leak. We ran the engine on the lift to get it up to operating temp and still no leak. I drove it home and it sat in my driveway for a day and I drove my truck and it did not leak at all. I drove it again, brought it home and it leaked like a sieve. I watched it drain the entire overflow tank, but not the radiator, just the tank. My mechanic thinks that it is the metal tube that goes across the front of the engine on the bottom that also feeds the oil cooler, but we can't seem to make it leak. I saw that there is an after run auxiliary coolant pump and was wondering if this could be my problem. The strange part is that the leak is intermittent and leaks from the overflow tank to the thermostat and dose not drain the engine or radiator, so the leak appears to be south of the overflow tank.

Has anyone any experience with a problem similar to mine and what did you do to fix it?

BTW I changed the TB and waterpump at about 100k and the car runs fine except for this damned coolant leak.

Anyone have any Ideas?

Thanks in advance for any help that you guys can give me.

Robert

 

Could be any one of 11 different hoses! Not much help, but here is an approach you can take. Go get some spray on foot powder. From under the car, spray the white powder everywhere you can. Drive the car until it leaks again, renewing the powder if it rains. When it leaks, look for the path through the powder and follow it up. You may want to remove the various engine covers for this experiment. Eventually you will find the drip. From the drip, work your way up to find the leak.

Good luck,

Bob

 

I am having a similar problem with my '02 A6 3.0L. I changed the waterpump and the only thing in the front part of the engine where the pink residue seems to accumulate is the pump... So, my guess for me is that I did not seal the waterpump properly. I have to replace a broken serpetine belt pully so I plan on checking out the area. I bought a new water pump gasket just in case...

Let us know what you find!

 

I have a similar leak. A6 2002 3.0L. Any of you got this fixed? Please help.

Thank you!

 

My problem turned out to be a poorly sealed water pump. When I had the timing belt and pump replaced at 100,000 miles, the fellow who did the job, did a poor job of preparing the surface on the water pump and it started to leak at around 130,000. I have since found an outstanding indie Audi mechanic and he did a proper timing belt, water pump, thermostat, and all related parts and she has run well since then.

If your A6 is close to needing a timing belt, get it changed by a good mechanic and be sure to replace all the pulleys and associated parts. You should replace your belt at least every 75,000-85,000 miles. It is an expensive PITA but the alternative is a VERY expensive engine rebuild.