I own a 1992 300CE with 81,000 miles on it. The problem i am experiencing is a annoying and embarrasing chirping sound from under the hood. I have a new water pump and serpentine belt and new shock for the belt tensioner. At times the noise is loud and the belt is free of fluids etc. Any suggestions are highly appreciated.Other times the noise goes away for a day only to return. I had a good reputable mercedes shop look at it and they replaced the shock for the belt tensioner but the noise still comes back a lot of times.
Thanks for any advice that anyone can give.
Phillip

Phillip,

It sounds like your belt is loose as I think you suspect. Do a search on serpentine belt tensioners for the M103 and M104 for the info you need. Check to see that the tensioner is set properly. If the indicator points to the proper mark and the belt feels loose, then the tensioner has failed or will soon fail. There is no end of information on this site on how to replace the tensioner.

Sixto
91 300SE
81 300SD

it's been my experience that tensioners usually fail shortly after any repair requiring loosening and readjusting the belt(repl. pump or belt)
MF

Mike,

Sorry to go off topic. Did you post that you have a shop that rebuilds transmissions?

Thanks,
Sixto
91 300SE
81 300SD

OK,thanks for the tip...I will look into replacing the tensioner.
Phillip

Thanks for the responce...very much appreciated. The MBZ shop may have missed that one. They said that the belt is very tight and it is new. I will double check the tensioner.
Phillip