SanJoseS7

New forum member, 1st time Audi owner, 1st time turbo owner.

Bought a new 2017 S7 Prestige Arras Red in January. Currently 5800 miles.

Turbos were clean when I took posession. Recently popped the cover and I notice what to my eye appears to be a leak from both turbos, with apparent burn residue.

From studying the Audi 4.0TFSI Engine Self Study (920223) it is most pronounced on the coolant return side, but also appears at a reduced level on the supply side. My coolant tank is also low, below the min line.

Is this expected in this vehicle?

I've made an appointment at Stevens Creek to have it looked at on Friday.

In all other respects, she's a tigress and a masterpiece of engineering.

Thanks for your input.

Frenetic

I noticed that discoloration on the coolant line housing (or what I presume are the coolant line housing) two weeks after I took delivery of my brand new car. This photo was taken when I first noticed it (two weeks after I bought it).

I googled it extensively and there is a TSB for a coolant leak in that very area, but from what I saw in the photos, the coolant leak is easily seen on the top where the stainless lines enter the turbo and it looks like a mound of crust.

Based on your photos and other photos that I have seen (and my own car), I almost believe that discoloration is typical and maybe normal if you can believe that. It may be due to high heat or some other mechanism that is occurring, like possibly condensation even during a cold engine and that area filled with coolant, then it rusts (speculating).

SanJoseS7

Closing the loop on this. Stevens Creek reports this is normal wear on this part and expected. I had the service manager do an additional inspection to confirm.

Apparently this is a cast part so it is vulnerable to corrosion/rust. I did not get a clear explanation of why - perhaps one of you can explain. Maybe high temp on coolant return? Anyway, dealer states this is essentially rust. Any idea why some alternative manufacture method is not available for this part?

He says they could scrub it off with wire brushes, but it will return immediately.

To confirm, I had dealer open a random A8 with 4.0 TFSI and it was 99% clean. You could just begin to see a very slight coloration in same places, I assume from test drives. Then I went over to CPO and had them open a random A8 with 20K miles on it, looks exactly like my photos above.

Combined with Frenetic's photos I'm willing to accept this as normal. Certainly messes with the clean look of the turbos however.

BTW, I got the head curtain airbag swapped as well, so those parts are now available.