hippotester

My '05 A8/D3 is sporadically leaking coolant from a small plastic tube between the oil cooler and the block. It doesn't seem to be leaking while running and after stopping but at some point during the cool down period when it occasionally disgorges a fair amount of coolant. Audi repair procedure specifies pulling engine and cross-member to replace a small plastic coolant pipe with O-rings. Internet has posted a procedure that does not require pulling engine (complete with good instructions and pictures) that only takes about 7 hours or less. Does anyone have any experience doing this? Are there other ways to address this leak?

dvs_dave

Try putting some leak stop in it. I know a lot of folk will reel in abject horror at that suggestion, but it's worth a try if you don't have the appetite to fix it properly.

I have the aluminum upgrade pipe if mine ever goes that you can get off the net (Bufkinengineering) for not much that fixes the issue but needs to be fitted of course.

When I had my timing belt service done I asked my guy if he could fit this pipe whilst he was in there. Apparently no savings to be had as you have to access the cooler from the wheel well and not the front. He quoted 7-8 hrs to do it but advised I'm best off sorting it only if it becomes an issue rather than preventatively.

hippotester

Thanks for the feedback. I've had bad experience with putting leak-stop into my other A8. Heater aux water pump solenoids never again had the same flow rate as before. Probably the clearances are too small for stop-leak not to affect them. Does anyone know any mechanics in NH or VT that do the 7 hour replacement procedure without pulling the engine?

jamm220

I just did this as well, mine wasn't leaking yet but I had the front off doing the tb job. That mechanic is greedy sure it's somewhat done through the wheel well but having the front off it took me probly two hrs and that's because I was being careful not to strip the bolts.

Most challenging part is the bottom bolt towards the rear and getting the top exhaust manifold stud out to access the middle top bolt. After removing the front I also remove the part where the front impact bar bolts into. It part of the frame about 12 inches lunch and has about 6 tripple square bolts in it.

hippotester

Are we talking about the same job - the removal of the oil filter cooler assy in order to replace a small plastic pipe between the cooler and the engine block? The shortest time I've seen anyone claim for the job is about 7 hours. There is hardly any room to work, which is why Audi specifies the engine removal at 30 hours. Even though I've seen the 7 hour approach documented on the internet, I've found no one that is willing to try tackle the job in that way.

jamm220

Same job but I had to do the tb job so that takes care of some of the labor as far as getting the front off which makes the job a lot easier

Bmw e65/66 says it require engine removal for a $5 gasket behind the alternator housing which I've done without the engine removal on my car before

NYCA8L

I DID THE REPAIR LET THE SHOP HAVE THE CAR FOR 4 DAYS NO RUSH AND COSTED ME 1300 FOR THE ENTIRE JOB I BOUGHT THE GRUVEN REPLACEMENT METAL PIPE AND HE BOUGHT THE REST OF THE GASKETS AND ALL. ALSO WANTED TO USE BARS LEAK STOP LEAK BUT HESITATED AND IM HAPPY I DIDNT DO IT.

mishar

I used some stop leak and I am happy I saved $1300.

ltooz_a6_a8_q7

seal anything, how does the chemical know where to seal? it just sticks to anything that it can stick to or seals anything thing it found? Now that's scary. Just wait until leaks a lot then replace the pipe. Someone up here did it, not easy, but not hard either, just need to remove and loosen many things that's in the way of bolts and nuts. I wouldn't use the aluminum tube either, I don't think Audi engineers didn't think of metal tube, it's the heat and the rubber ring. Aluminum dissipate heat slower than the plastic tube heat. The rubber ring would be exposed to heat longer every time you drive and park, off and on. Aluminum will expand and contract with heat, then the ring will be compressed and released more often. The rubber ring will go quicker although you have your "Non broken pipe", you will have oil and coolant mix as soon as your after market rubber ring goes out due to heat, compressed and uncompressed. I remember I used to hate thermodynamics and materials classes, but I still remember some... hopefully it's correct.

Cheers,

Louis

nismofreak1208

I'm pretty sure I had this coolant leak as well, I used some K-seal ST5501 all purpose which states that you do not have to flush the system after using. Its been 1 month and my coolant level hasn't changed. Usually between oil changes or 4,500 miles, my coolant tank would lose about 1/5 of its capacity. The leak was coming from somewhere on the bottom but I couldn't see anything anyway. I could only see the coolant on the engine splash guard panel.

Also used lucas oil stop leak as my valve cover gaskets have started to leak apparently. Put it in about a month ago and oil level is still good.