RATTLE air filter housing I have searched and searched please help - PeachParts Mercedes-Benz Forum

#1 11-19-2004, 07:19 PM

I have been searching like the dickens for why my 300 cd 617 has the air filter housing rattle!
As a side note... it did not rattle when I got the car a couple months ago, is was vibrationg bad at idle, and I changed engine shocks, shock mounts, shock bushings, and voila!

no more shake!

Well as any good DIY mechanic, (pun intended!) when fidling with a few things I noticed (actually I was cleaning the engine) when I pulled off the air filter housing, that one of the rubber mounts for the housing was broke in half

so I ordered new ones, and even though my car did not have them, I ordered heat shields for the rubber mounts. Put them all on and the filter housing started shaking and rattling!!! Drat, I pulled it back off, pulled the heat shields, reinstalled mounts...no avail still rattling By the way it rattles only at regular idle, little fuel...smooths right out. Also if the engine is sitting there running, I can push down on the housing...and no rattle. The engine is runing smooth as silk, but the rattle is annoying me. Please Help

Joe
82 300 CDT 125k

dieseldiehard · #2 11-19-2004, 07:42 PM

One cure for this seemingly normal problem is to stuff a piece of rubber between the housing and the cam cover. I used an old shock bushing, I cut it in half to make it thinner, it solved the problem. You may want to tweak the rack dampner pin, to smooth the idle, even adjusting the idle speed can affect the amount of shaking that the filter housing makes. Its a pity the filter in the Federal (non-CA) diesels wasn't remote like the '85 CA models (and the OM603 in the W124 models)

#3 11-19-2004, 08:51 PM

Diesel,

I just remembered... when I first removed the air filter housing, (to clean) I found this old large piece of rubber bushing (looked like a large shock bushing) laying near the valve cover. Obviously this was the last owner's methodology!!

Thanks,

Joe

tangofox007 · #4 11-19-2004, 10:32 PM

I had the same problem. It was difficult to actually see, but the air cleaner housing was hitting the plate on top of the valve cover that holds the 3/2 valve and some of the accelerator linkages. I took a 2 inch piece of heater hose, split it longitudinally, and placed it between the filter housing and metal plate. It would fall off every few days until I punched a hole in the hose and secured it with one of the bolts that holds the plate to the valve cover.

SD Blue · #5 11-20-2004, 11:14 AM

When was the last time the valves were adjusted?

Someone here on this forum mentioned how an old German mechanic taught him how to do a valve adjustment. Since using this technique, I have had very little rattling.

The "technique": Lube the feeler guage with oil and ensure there is absolutly no drag on the guage while checking. After making adjustments drive it for at least 100 miles and let it set overnight. Recheck clearances with the lube oil and feeler guage. It takes longer but is worth it.

I was surprised how much difference this made in smoothness! Bare minimum of shaking on cold start up and smooth when warm.

lietuviai · #6 11-20-2004, 01:13 PM

Quote:

Originally Posted by dieseldiehard

... Its a pity the filter in the Federal (non-CA) diesels wasn't remote like the '85 CA models (and the OM603 in the W124 models)

Yeah but the filter costs from about $25 to as much as $40

at some places and the filter is hard to find. Plus with that filter system you have the dreaded trap oxidizer that robs power. I dumped that system from my '85 and it made a big difference in power and responsiveness.

ayalar007 · #7 11-20-2004, 01:30 PM

joer2001,

I just finished doing that to my car and had the exact same thing happen. But, I noticed that the oil return tube underneath the air cleaner housing was not put in properly. Second I found that the bracket had weakend and was allowing for more rattle. So I replaced the bracket, bought 3 new rubber dampers with heat shields and used pressure washers and lock nuts in the cleaner to hod it down. Also, the positioning of the air cleaner has alot to do with it. I found that by using the front holes vs the rear holes made a huge improvement.

I know it all boils down to idle, so if you have a rough idle, you'll have to check that out. The rack-dampner bolt is a must as is the valve adjusments!

Good luck!

dieseldiehard · #8 11-20-2004, 01:30 PM

I wasn't promoting useing a trap oxidizer, only the big filter cannister that the '85s used, yes filters are a little more costly but some say they do a better job of filtering than the flat ones.
At least you wouldn't have to replace the darned filter brackets that tend to fail every so often, leaving the filter flapping all over the place. The cost of a new bracket is more than a few filters as I recall.

My solution to the problem of broken brackets on the '85 engine in my '79 300TD was installing a K&N filter. That opened up the need for a suction line to the external separator (from a 240D). K&N's don't filter as well as the OE paper filters (according to many) but I don't drive that car very much so whether or not the K&N is better at trapping dirt is not of interest to me.

lietuviai · #9 11-20-2004, 01:39 PM

DDH, I wasn't implying that you were advocating the use of the trap, just that that was the reason why those cars had the filter system. When I had the canister, it seemed to collect lots of garbage so I jokingly called it the "garbage can". The filter would need regular cleaning before eventually needing replacement and I never drove the car on gravel roads. I wouldn't recommend using the K&N filter since even though you don't drive your car much, what little you will drive may still do some damage to your engine. I have heard about the regular failure of the brackets and mounts but as long as you have a smooth running engine with good engine mounts, it shouldn't be too big of an issue.