Noisy Engine and Vibration, Mercedes 2001 CLK320, I love this car!

I need a diagnosis. My 2001 Mercedes CLK320 has ~150k on it. The maintenance, etc. has been kept up to date. A few months ago the car engine started to run noisily and began to vibrate. It’s worse when it’s cold out or if the car is at stopped but not in park (like when you’re at a stop light or drive thru). The vibration and noisy engine running lessens considerable after the car runs for a while and if the car is in park. I already had a tune up by the MB dealer about 9 months ago.



Diagnosis? Also, I’m obviously at that point where the dealer service shop no longer makes sense. I’m going to drive this car (hopefully) beyond 200k, however, it would be nice to get rid of this problem. Otherwise the car really is almost as good as new!

Could be a lot of different things, not enough clues to diagnose. Is the check engine light on? You’ll probably have to take it to a mechanic that know MB’s.

And Benz over…

Every thing else is fine with the car. No engine check lights or anything else wrong. I had it in for a check up/tune up about 9 months ago. All my Service Requests are up to date – Service type A and Service type B.

Any ideas of what would cause these issues?

Just a few wild guesses; could something be loose such as an exhaust component or could there be a broken motor mount? Heat shield touching the exhaust pipe?

Can you notice the problem with the engine running at a fast idle? Put it on a lift, look and listen.

Sounds like you could have an engine misfire…but your CEL should be going nutz over that type of issue. Not too much info to go on here Im afraid.

It sounds to me as though you have a faulty plug or injector that begins working after it heats up… I’d start on the cheap side and replace the spark plugs. I mean how do you know when they were last replaced? Have they been replaced yet? How about your air filter…these are all tune up items.

This is what I would do…Run a bottle of Chevron Techron Fuel injector cleaner thru the gas tank to clean up your injectors (while orig plugs are in engine)…it comes in several types…buy the one thats around $15 bucks and run a tank of gas thru it…THEN…REPLACE your spark plugs and Air filter if that hasnt been done either ( A PCV Valve wouldnt hurt either…another cheap item)…Basically you are cleaning your fuel system and then doing a tune up…All good ideas and ones that sure could help solve this. These are three inexpensive items to do first…see what you get. I think it will fix it…if it doesnt we can then move on to more expensive items.

I’ll see. I don’t have a lift so I’ll have to get with a mechanic. Thank you so much for the insight!

Thank you so much for the VERY well thought out approach to the issues!!!

I will see if this helps!!!