C5 A6 2.8 Idle Rattle

[C5Manny]

Hi my daily is a 2.8 and I have a rattling/crackling kind of noise from the engine bay during idle while in gear. It goes away while in drive usually. There are rare occasions when it still rattles in park. I've heard a/c clutch as well as cat internals and motor mounts. Just wanted to get some of your opinions on possibilities and how to rule them out.

[Audi4.2!]

Cam chain tensioner. My 4.2 was doing the same and if found the plastic pads on the cam tensioner broke off. Apparently the wear out over time. I'll try and find a pic

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[Audi4.2!]

https://cloud.tapatalk.com/s/57c97b95...25_160552.jpg?


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[Audi4.2!]

Here's a good one.

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[Audi4.2!]

Here's a bad one. Notice the chain is sitting on bare metal and when it's running it rubs on it hence the rattle.

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[C5Manny]

https://cloud.tapatalk.com/s/57c97b95...25_160552.jpg?


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Nice alright thank you and was it diffucult for you to swap it out or did you have it done?

[CAL4.2]

Cam chain tensioner. My 4.2 was doing the same and if found the plastic pads on the cam tensioner broke off. Apparently the wear out over time. I'll try and find a pic

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How many miles did you have on your AWN 4.2 when the guide/pad broke?

[Audi4.2!]

C5Manny, I did it on my own. It's not too bad if you've done your TB before. The process is the same in locking your timing down coz you have to take the valve cover off and unscrew the cams to lift work the tensioner out. You also need a special tool for the tensioner. I got mine at blauparts.com and the have step by step instructions. This happened at 193k miles so i went ahead and did the TB and water pump as well.

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