Aviator6

I purchased a 2012 A6 Prestige, 3.0T, late last year. The 35K service had just been completed by the Audi dealership where I purchased the car. I am not comfortable with going 10K miles between oil changes, so at 42K, I did my own oil change. When I removed the drain plug, I noticed that there was no crush gasket installed. I assumed that the last person who performed an oil change(may not have been the Audi dealership as my understanding is that they pump the old oil out through the “dipstick” tube), simply omitted it. There was no sign of any oil leakage at this time. I had a good supply of 14mm crush gaskets, so installed one when I replaced the drain plug. After refilling and starting the engine, I checked for leaks, but did not let the engine get to normal operating temperature. Well, several weeks later, I notice oil on the garage floor. It took that long for the leak to become evident, as the under-belly pan is of a material that will absorb some oil. I assume the fibrous material is for sound insulation?
Did some searching of the forum, questioned an Audi tech, but could not get a definite answer if this engine uses a crush gasket on the drain plug. Decided that since it wasn’t leaking without the crush gasket, I would remove the gasket and see what happens. Removed the crush gasket, cleaned up the spilled oil and voila!, no leaks. I cut the under-belly pan and installed a hinged, access door so I could monitor for leaks without having to remove the pan. A couple hundred miles later and no leaks.
So, does anyone have a definitive answer, and please no guesses, does this engine use a crush gasket on the oil drain plug.

Note: I also posted this question on the 3.0T tech forum.

BillBoost37

I recently did a change on my C6 (2010) and it had a washer. However most suggestions were not to replace it unless it began to leak.

Having spent some time looking into the same, I found that ECS Tuning has a kit that includes everything possible for oil change. I call it their kitchen sink kit. It includes a small washer. Almost looks like a shoulder washer.
Audi C7 A6 Quattro V6 3.0T Engine Oil Service - N0160276KT - Oil Service Kit - ES#2535605

a44mark

Yes, the 3.0T oil drain uses a crush washer. I looked it up in the repair manual and it's clearly on the exploded parts diagram. FYI, I had the same slow leak as you a few months ago - I was surprised one day to see an oil spot under my car after work! When I got home and had a chance to crawl underneath, I saw the felt on the belly pan was soaked with oil - freaked me out because of how much was there... I had changed my oil (myself) a couple weeks before, so I probably didn't tighten the plug enough. I torqued it a bit more and it was fine. The manual says the torque is 30 Nm (22 ft*lbf), but I probably needed a bit more to stop the leak.

-Mark

dshahs420

Changed my oil in 2012 A6 in April and it does have a crush washer.

Aviator6

Thanks all for the replies. Next oil change I'll use a crush washer that I'll purchase from Audi parts, and then monitor closely for leaks.

Aviator6

Had my 2012 A6, 3.0T to Audi dealer today for state inspection. Service advisor stated that the 3.0T engine in the C7 A6 does NOT use a crush washer on the oil drain plug. I find it incredulous that there is so much variance on this issue!!

a44mark

I don't see any room for debate... here's the diagram from the C7 A6 repair manual. The washer is item 31...

IknowHuhA6

Had exact same issue. Was very angry at all the oil I found on the felt cover. So I realized the plug needs to be sprayed with brake cleaner to remove any particles that could cause a leak. Then also used a washer from local auto parts store. This fixed my problem but the large oil stain on my cover remains. Absolutely burns my britches. LOL.

As with anything, all high performance or high maintenance sophisticated machines have their own little quirks. Experienced people know about these but this doesn't mean the service techs at dealer working on your car are "experienced". They could be newbies following white-papers written before things were discovered.

dshahs420

You need a new dealer to work on your car. I've done 3 oil changes in my car and have used a crush washer each time as the car came with one on from factory!