Rattling under car in idle / drive
 

My 1993 190E has started to make some nasty rattling noises

I noticed it tonight after dropping off a friend and my door was open. the car was idling in D with my foot on the brake and there was a loud rattling coming from under the car.

put the car in neutral, and the rattling went away. put it back in D and rattle came back, but if I apply throttle while holding left foot on brake, the rattle goes away.

does anyone know what the source of this is? I also have a 1989 300E W124 that does this same exact thing.

Possibly bad motor mounts causing the exhaust pipe to rub against a heat shield.

It is the top rubber bushing on the belt tensioner shock eyelet

There is an easy fix by sliding an O ring in between the bush and the bolt.

http://catalog.peachparts.com/ShopByVehicle.epc?q=1993-Mercedes--Benz-190e--.6-Cooling--System&yearid=1993%40%401993&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6132%3AMBC%7C1486%3AED%7C10 000011%3ASM%7C847%40%40190E+2%2E6&catid=240909%40%40Cooling+System&subcatid=241025@@Acc%2E+Belt+Tens ion+Damper&mode=PA

Search Tensioner Shock .

http://www.peachparts.com/shopforum/showthread.php?t=26091

CC
 

Your catalytic converter is shot. I cant remembe if there are 1 or 2 on your car. If there are 2, then get under the car and hit each of them with a hammer to find out which one has fallen apart inside.

cant be the catalytic converter, its brand new. I replaced it because my old cat broke and the symptoms are different this time. car revs really smooth throughout rpm ranges and doesnt make any rattling when I drive, its only when I am idling with the brake on in D.

I'll take a look at that belt tensioner shock, forgot about that one, along with the motor mounts.

thanks guys :)

Pretty hard to beat Dalton's advice, but I would have to say this is a pretty likely candidate as well.

i think its the engine shock. I wedged something in there to keep it from vibrating while someone had it in D with brake and the rattling seemed to disappear. so I'll have to get that replaced

Check your motor mounts, you should be able to clearly see the black rubber underneath the heat shield on the left side, if it is pancaked it needs to be replaced. You can also try rocking the motor back and forth when it is stopped. If it has no give that is also an indicator that the mounts are cooked.

Yes, that is it..very common.
It is the top bushing ...the glue that holds the rubber insert to the bushing sleeve dries up , allowing the top eyelet to rattle like hell. By sticking a large screwdriver in between the eyelet and the mount, the rattle ceases.
If you look close , you can actually see the top of the shock moving rapidly sidways. That is the metal to metal rattle..the bushing is actually still good..it is the glue that has dried up. So, there is a very simple solution...You can replace the shock/damper or you can simply sandwich an O ring the size of the eyelet in between the eye and the mount,, Just take the top bolt out, slide the O ring in, like a washer and re-install the bolt.. The ring just takes up the side movement space of the bushing. Several here have used this tip of mine and it last for years....and cost 50 cents.

A very annoying rattle common to all the chassis that used that Tensioner/ Damper system..Later chassis used a different tensoner that did not require the shock/damper.....so it was eliminated on the late 124s..........

Rattle
 

Good advice from Dalton.

I had the same type of problem on my Jeep. It turned out to be the cats...