When I rev to 1500rpm and release the throttle, I get a rattle/resonance from under the valve cover towards the front of the car. I've read the posts about the the two chain tensioners going bad or a bad vanos. So I took it to my mechanic, who listened to it and said it was normal for these cars. He said it was the vanos switching back to its low speed setting. Is this ok? Should I worry about it? I was ok with just leaving it as is, until I pulled into the garage tonight and hear the noise quite distinctly.

Originally posted by rpM
When I rev to 1500rpm and release the throttle, I get a rattle/resonance from under the valve cover towards the front of the car.
I had the same problem a couple weeks ago. I swapped out the main chain tensioner and the noise is gone. The install is really easy, all you'll need is a 32mm wrench or deep well socket, but the part will prolly cost ~$100. The new one has quite a different design than the original one.

Thanks bimmer95, is there any online how-to's on this procedure? Also, you didn't need to replace the other tensioner? How would you know to replace just the main or both? If I can't do it myself, how much labor should it be for a shop to do it? I've heard it took someone else 15 minutes, but I'm sure a mechanic would charge more time than that...

Originally posted by rpM
Thanks bimmer95, is there any online how-to's on this procedure
There probably is one somewhere, but I don't remember seeing it. Basically look on the front/passenger side of the engine block just above the AC compressor and you'll see a 1" diameter 2" long thingy sticking out. Grab a 32mm wrench and unscrew it from the block, have some paper towels or a rag ready because it'll leak a little oil. Grab the new one, either reuse the aluminum sealing ring off the original one or put on a new one, make sure the channel machined in to the end is vertical to match-up with the piece it pushes against inside, put some pressure on it to collapse it enough to get the treads started and tighten it down. Done :D

Replacement of the secondary tensioner requires removing the valve/cams cover. You'd probably want to have a Bentley manual handy before trying to replace that one. Just do the main one first and see if it fixes your problem.

Thanks again, bimmer95. I think I found a pic of the tensioner. While looking around on my own car, I stuck my hand down under the tensioner to the front of the block and found a huge buildup of oil/sludge. It's not coming from the tensioner though. When replacing with the new tensioner, what is the torque specs? I also read somewhere that on some tensioners (maybe not this engine) that they need to be primed with oil from above before starting the engine or damage can occur. Do you know if this is true?

Thanks again

;)

Jon Caldito, any insights?

Originally posted by rpM
I think I found a pic of the tensioner.
That's the one. The newer style doesn't have the hex head cap on the end though, it's all one piece. I'm not sure of the torque spec for it, I just cranked on it with a 32mm wrench. Based on the layout of the engine I'm not sure how you would be able to prime it before starting the motor. I just started my engine and let it run at idle for about 30sec or so, seemed to work okay.

rpM, the torque setting for the main tensioner is 28 lb/ft.

Originally posted by UD///M
rpM, the torque setting for the main tensioner is 28 lb/ft.

Thanks UD///M. I'm assuming I would use a 32mm crescent wrench to remove and replace the tensioner. I've only seen ratchet type torque wrenches. Maybe this is a dumb question but how would I torque it in this case?

Thanks.

You could look for a 32mm crows foot. However when you use a crows foot for torquing, you must multiply torque setting by the new lever arm.

To do this assume that the wrench itself is length L. That is measured from the center of the handle to the center of the socket head. The crows foot or other extended attatchment (don't confuse this with with the concentric type of extension. those dont change the lever arm)

Here is a pic I tried to put together to illustrate.