TDI Coolant Leak from Oil Cooler / EGR - Owner Repair Stories
 

We share/d a lot of information regarding this issue, needed parts, links, etc., on this thread: https://www.audiworld.com/forums/q7-...urvey-3035876/

I thought it might be informative for the "future us" to have a location where we can see visuals of other owners' experiences and repairs, so please post up your own photos, videos, tutorials, etc. for posterity's sake.

For me, I had a fairly significant leak in the "valley" of my 2014 Q7. Being just outside of the extended TDI warranty, I decided to research and tackle the repair myself. I ended up pulling apart the engine in early July 2022, ordered parts based on what I found, and put it back together a couple weeks later. Here are some visuals (WARNING: GRAPHIC CONTENT.) LOL:

All told, I'd estimate this job took me about 12-18 hours.

https://cimg3.ibsrv.net/gimg/www.aud...7d6456d8dd.jpg
Before starting, as a reference in case of mystery parts!
https://cimg4.ibsrv.net/gimg/www.aud...912ee02d94.jpg
With intake pipe removed, showing carbon buildup in the manifold. I cleaned all of this up in both the manifold and the pipe before reinstalling.
https://cimg6.ibsrv.net/gimg/www.aud...f643204d8f.jpg
Everything loosened up (wires, hoses, fuel lines, etc.) before removing the intake.
https://cimg8.ibsrv.net/gimg/www.aud...f760918a50.jpg
Intake removed. There was some carbon buildup in the heads, but it was extremely minor compared to the manifold.
https://cimg9.ibsrv.net/gimg/www.aud...b0fedc5035.jpg
EGR Removed; note the lake of mixed coolant and oil surrounding the oil cooler at the center of the frame.
https://cimg0.ibsrv.net/gimg/www.aud...b5818a4b86.jpg
Oil cooler removed; adapter plate (in the center of frame) still in place.
https://cimg3.ibsrv.net/gimg/www.aud...a6388fb3fb.jpg
Adapter plate removed and the lake is sucked out.
https://cimg4.ibsrv.net/gimg/www.aud...c9ca1ad121.jpg
Valley wiped up and ready for final cleaning.
https://cimg5.ibsrv.net/gimg/www.aud...d0bd5097f9.jpg
Final cleaning complete; view shows the front of the engine with both the thermostat/oil filter housing and water pump removed.
https://cimg6.ibsrv.net/gimg/www.aud...5f2249a1fa.jpg
Valley is ready for reinstallation!
https://cimg7.ibsrv.net/gimg/www.aud...37881840fe.jpg
Oil cooler, adapter plate, and EGR coolant bypass valve installed. Compare this to the fifth photo above (with the old oil cooler in the center of frame) to get an idea of how deep that lake was! I'd estimate more than a gallon of fluid pooled there.
https://cimg8.ibsrv.net/gimg/www.aud...a918df0638.jpg
EGR and intake reinstalled.
https://cimg9.ibsrv.net/gimg/www.aud...3c43bd4bf7.jpg
Fully reassembled and started.

Here is a first start video of my TDI:

I will be bringing in mine in a few months under the tdi warranty. I think it would also be helpful to have a comprehensive check list of everything to be addressed while in there whether covered or not. This looks like a good thread to cover. I think my service will be the engine out reseal


thank you.

Great work and thanks for the photos. I know the feeling after all that work and starting it for the first time after having so many connectors and pieces off the engine. Congrats. I hope I never need to do this job but will reference back if I do.

A comprehensive check list..... Hmm.... well, I think that other folks could probably add to this, and there are arguments about how deep one could really go to address "everything." I certainly won't claim to have done so, but I feel like I was reasonably thorough given my time constraints and budget.

#1: Take this opportunity to clean the carbon buildup from the intake and related components!
#2: Replace the rubber coolant hoses (three short lengths) that connect the oil cooler and EGR assemblies.
#3: Replace the EGR bypass valve and coolant adapter (the small black plastic unit that is to the right of the oil cooler in the photos).
#4: Reseal the oil cooler adapter plate and oil cooler. Both of these have complex, compound gaskets passing both oil and coolant, and both are subjected to constant vibration. Even if your leak is coming from one of the units in #3, you can bet that these gaskets aren't far behind.
#5: Replace any o-rings on coolant lines that you disassemble.

I think those are the must-dos.

Here are a couple optional items that are just much easier to do "while you're in there":

#6: Replace and/or reseal the oil filter housing and thermostat housing. New units include a new thermostat.
#7: Replace the water pump and bolts (if aluminum).

G'day I have a 2011 Q7 3.0 TDI and I presume I have the same problem . I was told at first that the valve cover was the cause of the oil leaking onto the alternator and had it fixed?
1 Did you replace the oil cooler or just clean it and new seals ?
2 The oil has been driping onto the alternator and now not charging and this was only 6 months old

Just had mine done. i was not going to tackle that myself. I thought about it but decided to let my local indie Mech do it.

I did replace the oil cooler, but I could have done the latter. Unfortunately, I was having a devil of a time finding part numbers for the gaskets alone, so I finally gave up in the interest of time and just replaced the part.

Interesting note about the alternator. I had an alternator failure last year (12/24/21, to be exact!), and boy, was it spectacular! When I pulled it apart, I also found that there was oil or *something* leaking down onto it from the front of the engine. It was my exploration of that source that led me to discover the "lake" in the valley, which was simply overflowing the front of the engine and dripping onto the alternator. I put a new alternator in at that time and put some aluminum flashing over the top of it to deflect the drip away from the sensitive bindings. This worked perfectly and the alternator remains in good condition (even though I didn't fix the leak until July).

I certainly thought about it, but I'm always a sucker for a good automotive project that's way over my pay grade! :D