Just fixed a similar leak on my 2001 A8... feel pretty dumb but initially thought the "pink fluid" on the floor was transmission fluid... flashback from my '69 chevy days I guess! After I realized it was coolant I dropped the "under motor plastic cover" to discover a leak at 3 of the bolts holding the front coolant pan to the motor (looks like a small shallow oil pan with many bolts around the perimeter)... this pan is at the very front of the motor underneath. Snugged up the bolts where the leak was and it has been dry since... I suspect to do the job right it needs to be drained down and the pan gasket replaced... I will deal with this if it leaks again or when I have the time to do it myself or get it to my local Audio guru. Hope this helps... If anyone is in the S. NH area and needs a foreign auto guru who is honest and knows german cars inside out hit me up and I will send the info on the garage.

 

Hey, thanks for the info. I am goingto try and tighten those bolts. I took of the plasticcover and I saw dripsthat looked like they were coming from between the seal on that pan. I was sure that was an oil pan and could not be dripping anti freeze. so I put the shield back on an have been doingwhat the dealer said (wait for it to break bad enough that theycould diagnose it). I love my A6 4.2. Nothing drives quite like it for me. That includes Mercedes CLK,several BMWs, Lexus IS and Infinity G37. However, I seem to not get one thing fixed before something else breaks. I haven't fixed the coolant, and now I am getting P0491, P0492. Well, going to go search for that.I know it is a secondary air problem, but seems like serveral areas it could be. From a fuse, to replacement of the pump.

 

Thanks guys. The leak actually has stopped, at least I haven't seen seen anything of any significance. I'll climb under and look for these bolts. I've actually been driving my 2.7T during the winter trying to discover any bugs in it.

 

Gentlemen, I apologize... the tightening of the front lower pan bolts and the leak stoppage must have been a coincidence. Started getting a few drops again after a couple days. Need the car to be reliable so I called my trusted german mechanic... turns out the pan I tightened up is in fact an oil pan. I would have bet money the leak was emerging from the gasket in the area of the bolts I tightened. Mechanic tells me it is a common misconception due to the way the leaking coolant trickles down from above. The actual culprit is the water jacketed oil cooler that is right above the area I mentioned. He said initially it sounded like a common O ring leak. After digging into it he found the the water jacket on the oil cooler unit was cracked. Bad news from a $$$ standpoint ($700 part).

Mechanic is a trusted friend so I know this is the real deal... would not have trusted a dealer mechanic, but this guy is true blue.

Sorry for the misleading info... again, strangely enough the leak seemed to stop after tightening the bolts but it could not have been since it is an oil pan... I guess I need to go back to my small block Chevy tinkering!!!!

 

No problem. Its a hard leak to find, Particularly when it doesn't leak all of the time. I'll deal with it eventually. Luckily, I have several vehicles anddon't have to make this a rush.

 

Just to give an update on the coolant leak. The leak was coming from the oil cooler. I took to the shopbecause I noticedit was running hotter than normal. All indications pointed to the thermostat and finding out that this was true, I had everything done (timing belt, water pump, etc..). The cooler was damaged and had to be replaced. The total cost was $1740.00 but I dont know how much of it the timing belt, cooler, etc. Hopefully, I'm done with any "big money" repairs for a while.