awbooth

Hi all!! I have an 05 C240 AWD. When starting the car we are getting a whining noise coming from the pulley/belt/water pump area. I can't tell if it's the belt which was replaced about 4 years ago, or the idler pulley which was replaced 4 years ago or the belt tensioner assembly which was never replaced before. The belt looks perfect, and of course pulleys look like pulleys but I don't know how the belt tensioner is supposed to look like or sound like. Meaning the aluminum rear body of it has a slight movement back and forth as the vehicle is running and the belt is spinning. I suppose I could replace the belt, idler pulley and tensioner for about $100 off of Amazon prime purchase...however could it be the water pump?? Any suggestions? thanks!
Anthony

mrobinso

Funny when I purchased my 2005 C240 wagon late last year with 100,000 miles the owner noted the same type of whine. Having had bad experiences with the idler and tensioner pulleys going bad I replaced those and threw in a new serpentine belt while I was at it. Got rid of the noise. I thought it was a water pump too but figured I would do the cheaper repair first. I would say after four years you are probably due for a new idler pulley and if you have never replaced your tensioner pulley then I would say definitely replace that as preventative maintenance. The tensioner pulley comes off as one full piece including the metal bracket it is affixed to.

awbooth

Sounds good, thx!