Quote Originally Posted by mik15 View Post
which oil cooler? i know a friend of mine had the same issue with an ML 63AMG and it was the gearbox oil cooler, i think it could be the same here...if so he should also change the gearbox oil as it has coolant in it now...definitely don't drive it anymore cause you can damage the GB and get the engine temperature too high and boil it!
Hi, mik15
Thanks for your reply.
But now you guys confused me.....
The oil cooler MaxRS6 told was the one on the engine itself that cools engine oil, right?
And the one you are talking about is the transmissiono oil cooler located below radiator?(#Part# 078117021D)

How the oil get into coolant reserver tank if it's transmission oil cooler?
Are they connected somewhere? I guess, they are not supposed be connected but located pretty close each other.
But somehow, gear oil and coolant mixed at somewhere.....
If that the case, do I need to replace the transmission oil cooler and flush the gear oil and replase with new gear oil, right?

I will talk to my mechanic about it tomorrow.

Best regards,
Coco