rsd911

Due to all the emails I have been receiving, I have summarized this procedure for all those owners who have experienced the notorious coolant leak from the right side of the engine block. I imagine that eventually all 4.2 owners will need this fix due to the design flaw. If you are mechanically inclined and have the tools, I would suggest doing the job yourself.

The coolant leak drove me absolutely nuts for 6 months. I replaced the water pump and hoses with no success......that was a huge job in itself. The local Audi dealer stated I needed a new head gasket, so I figured I would try the following procedure as a last resort.

What happens is that the plastic union between the block and the oil cooler cracks and leaks coolant . The leak will appear around the right side of the oil pan(at the backside)

The procedure is as follows:


1.Drain all coolant (there are two drain ***** on the block L + R sides).
2.remove oil filter
3.remove alternator belt, alternator and plastic breather
4.undo swaybar from passenger side (loosen drivers side)
5 remove passenger side rear engine support (unplug wire from it first), and bracket
6. go nuts removing the 5 or 6 hex bolts that hold the cooler in place ( the top ones are a bitch and will likely take you a few hours to undo and reinstall)
-if at this point you think that this is impossible..it almost is...........but persevere....you will get it done!

7.Inspect the plastic pipe for cracks and then after you are done swearing at the $8 part and you smash it with a hammer like I did, you can install the new one with NEW o-rings.

Reverse the procedure outlined above for re-install.

Caution! Don't overtighten anything......the block is aluminum.

Here is the parts list off the top of my head:

-o-ring kit for oil cooler
-o ring kit for plastic union pipe
-o- ring for metal coolant pipe
-vw/audi pentosin coolant (8 litres)
-distilled H20 (8 litres)
-new oil filter and washer
-new accessory belt since you are at it

I think the total parts were $50 plus the belt and coolant.

This job is all labour!

Count on 8 hours and Goodluck!


R. DIOCEE
Winnipeg, Manitoba

Egil A64.2s - S6

If I need it done I'll send you a ticket and you can come and do mine ;-)

Probably cheaper than the dealer!

JimR

For pre-facelift A8s. Might be useful to look at, even though the procedure is different.<ul><li><a href="http://www.audipages.com/Tech_Articles/enginemechanical/oilcoolerremovalreinstall.html">Oil Cooler Removal and Reinstall</a></li></ul>

derrickb69

I just started having a severe leak coming from the back of the engine in the middle

SloopJohnB@mac.com

I've done it...here's some pics.
Do the alternator VR (brushes are worn) if 140K miles or more or close to that.
check your motor mounts...my front one was sheared.

LOL...you'll probably have to put the front end in service position.
Highly recommend some kind of magnetized 8mm hex bit driver or maybe a short ball tip hex bit for that danged center top bolt.

derrickb69

When removing the passenger side rear engine support and bracket, do I need to support it with anything while it's removed?

SloopJohnB@mac.com

I didn't. But I replaced my broken front engine mount first!
It probably wouldn't hurt to put a jackstand underneath the engine somewhere solid but as I said, my engine didn't move one bit.

williagw

I had a coolant leak that I did not notice until after I did a timing belt change with all the amenities. I assumed it was the water pump or the thermostat, but was wrong after checking them. I don't know how long it would have taken to find the actual leak if I had not run across this article. Thanks for the help. P.S. Use an allen wrench with good flutes all the to the end when trying to get the allen bolts out holding the oil cooler/engine mount to the engine block.

4ringking

I am going to start one tomorrow, I will try to take a bunch of pictures.

Frank Israel

I'm in the process of replacing the pipe on my A6 right now as well. Unfortunately, between my ignorance and that of the parts guy at the local Audi dealership, I didn't get all the gaskets I needed. After this much work, I don't want to put the project back together without at least two more gaskets that he didn't order, and I didn't insist on getting.
These would be the o-ring gasket that fits on the external coolant pipe, Part# 077 121 437, and the figure 8 shaped gasket that seals the oil connection to the block, I think this particular gasket can only be obtained by ordering the set of gaskets for the oil filter bracket, Part# 077 198 405.

Oh well, I may just go ahead and order the after market aluminum oil cooler pipe from ebay, replacing the plastic one I got from the Audi dealer, while I wait for my gaskets to come in- now that I know about that as well.

One thing about getting out the much feared top bolt on the oil cooler housing (I thought all of them were challenging to some degree) I just don't think there is enough room to safely get that bolt out without lifting the engine a few inches on an A6. By safely I mean not subjecting the bolt to the possibility of stripping it. I had already removed the motor mounts on that side of the vehicle so sliding a jack under the engine (using a piece of two by six set flat under the oil pan as a buffer between jack and engine) and lifting the engine a few inches was no big deal. I was then able to get a visual and a straight shot at the formerly hidden bolt. In fact, by proceeding this way,the removal of that bolt the easiest and cleanest of any of the five in my humble opinion. I can't wait to put it back in