'07 Audi S6 5.2L V10 MAF sensor logging

[dafrazi]

Jack,
What kind and how much of a flexible sealer are we talking about? I always smear some copper rtv on the mating surfaces...just enough to coat. Are you suggesting to run a thick bead of rtv to lay the gasket in? rtv on one mating surface or both? I'll give it a shot. I didn't think it would be necessary since the gasket itself is about 3/16" thick. The manifold gasket has about a 1/16" thick silicone seal on each side of an 18 or 20 gage metal frame.

 

[Jack@European_Parts]

You could use RTV, Wurth/Hylomar DP series compound heavy and thick or even their flange sealant which is flexible high build.

I have seen this issue on a few cars with this being the corrective measure which was reasonable verse a new manifold.

You know........ you would think with a gasket that thick it would seal.....
The significant change in temps and the fact that the plastic is now made of a sophisticated blend of straw and human feces......need I say more?

I throw the gasket in the garbage where it belongs and prefer the Blue heavy Hylomar...
Winzer has it and it is on ebay etc.

This is an example not meant as spam.

http://www.ebay.com/itm/like/331161039314?lpid=82

 

[Uwe]

the plastic is now made of straw and human feces.

Yeah, but it's environmentally friendly.

-Uwe-

 

[Jack@European_Parts]

Last I checked straw and human feces were biodegradable.....but if you're in China, and eating the dog food which was rejected here in the USA in recent years....than its probably toxic.

Don't chew on your intake folks.....

 

[dafrazi]

I keep putting off this update: I checked everything Jack suggested and each thing turned out OK. So, I pulled the intake manifold to apply some sealant and low and behold I found signs of intake air blowing by the gasket and a small tear in the silicone portion of the gasket at cylinder 5. I didn't have a new gasket; so, i sealed it up the best I could and reassembled. This improved the LTFTs a little...they dropped from the 21s down into the 17s.

I ordered a pair of new gaskets to replace the ones on the car. While I was in there I swapped the #4 & #5 injectors (these are the injectors associated with the lean bank) with 2 "known-good" injectors that I had in the garage. I lastly double checked the torque on "ALL" the manifold bolts before reassembling. I crossed my fingers, said a prayer to the engine gods and went for an extended drive. I don't know which of these things actually fixed the problem, or if it was a combination of all 3 but, the LTFTs are now within spec.

I hope this post helps someone in the future.