Hello,

I have been experiencing a rattling noise coming from the engine-bay during startup.
My local audi dealership took a look at my car this morning and told me that the noise was a combination of a small exhaust leak and the secondary air valve.

The exhaust leak has been fixed but my mechanic tells me that there is nothing that there can be done to fix the sound coming from the S.A.V. as it is a common problem with other 2.7T models.

Does anyone else have experience with this problem?
If so were you able to find a fix?

Any feedback would be greatly appreciated.

 

That sounds like some sort of hooey!
If the valve is bad, then it needs to be replaced (along with a new vac hose probably). It will cost around $125 for the parts.

 

There is also gasket that is known to leak. The resultant sound is like a diesel.

I'm surprised the mechanic didn't speak of an incorrect flow DTC.

The gasket should be sold with the valve. Replace the gasket, and it should sound normal again.

 

Just an fyi:

During cold starts, the valve on the back of the head starts to pulse while the secondary air pump moves fresh air into the head under pressure. This air flows over the back of the exhaust valves causing a vacuum inside the exhaust side of the head.