Porsche Forum - Porsche Enthusiast Forums - Engine Knock & Headlight Haze

I have a 2004 Cayenne S that has a soft knock in the rear of the engine. The dealer said, the computer reads nothing’s wrong. He said, see if it gets any louder and bring it back and they'd open it up. There are no leaks and it seems to run fine. My question is....is there an additive, when changing the oil, that would quiet the sound or help it survive an operation? Maybe I'm making it sound worse than it is, but any noise worries me when it comes to these trucks, especially when it's out of warranty.
The tech. said, it’s a common problem, but he had no real solution.

Question 2: The headlights seem to be hazy, but I think it’s on the inside. I’ve cleaned the outside, even had them buffed, but it still there. Is there some way to fix this?

Thanks
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