I've had my 1982 300TD-T for 2 weeks now, and I'm getting around to all the little things that have been neglected for who knows how long...

One of those things were the rubber air filter housing mounts. When I took delivery of the car, I noticed that the housing was loose, but during the test drive it made no noise - even at idle.

So, I went out and purchased new mounts (and heat cups, which weren't there beforehand) from my local Benz dealer and installed them, along with new seals for the turbo-to-air filter-housing hose. (By the way, do those new seals add a little extra oomph above 2000 rpm, or is that my imagination?)

Anyway I now have a rattling housing at idle, and at speed going over rough road surface. Sounds like the housing smacking into the valve cover, definitely metal-on-metal.

The bracket itself is in rock solid shape. I've tried repositioning the housing using the two different mounting positions. I tried removing the heat cups.

Any ideas?

When I picked up my 83 SD two out of the three mounts were dead, I replaced all of them and also the heat sheild cups, yes the housing assembly looks like it vibrates more at idle than it did with broken mounts, but it does not hit anything, do the housing lid clips fasten tightly, they can make alot of racket, when idling or reving the engine can you see the housing hit the valve cover, did you get the correct mounts, one style is octagon shaped the other is circular, I do not know if there is a height difference but my 300sd had the circular mounts and thats what I replaced them with and have not had any problems.

yep, clips and nuts are secured tightly, with no play.

i'm now using OEM round mounts (purchased from the MB dealer), but the car came with the 19mm hexagonal mounts. all three of those were just hanging by a thread of rubber.

could it be vibration between the top of the rubber mount (which is metal) and the bottom of the housing? what about some type of thin rubber gasket between them?

I doubt that the stud coming out of the rubber mount would rattle, unless you do not have any nuts tightening down the housing to the mount. You did not mention the oil return pipe that runs from the bottom of the housing to the engine. There is a bracket that holds this pipe in place.. it could be loose and rattling. btw.. the nut and bolt on that bracket is easier to get to, if you have an extra set of joints in your fingers

hope this helps

-Larry

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09 Jetta TDI
1985 300D

No there is not a gasket between the housing and the circular rubber mounts, but the octagon shaped mounts do have more rubber on the ends, not saying that the noise is caused by the "new circular rubber mount's" but if the originals were octagon shape why did you get the round one's, there maybe a height issue, when I went to the dealer to get my "new rubber mount's" they pulled out the octagon shaped mount's, I had my old one's with me and said those are not correct, then the parts guy looked up the correct mounts and as I have said, no problems. Have you checked for clearance problems or is it possible to rock the housing manually to listen for any contact noise.