CoupeLeicht600

Hey everyone,

I wasn't sure where to post this...so I decided here instead of Tech Talk. I have the same post under the CL-Class discussion thread.

Got something for everyone to help me diagnose. I started up my CL yesterday morning, and of course, something unusual happens. The car started fine, but then I noticed a louder than usual howling noise. Normally, on the start up the car's engine revs high for a minute or two, but then the rpms go down. However, yesterday, while the car was on, there was a distinct noise between 1500-2000 rpms. When I started driving, the noise was still there, but if drove it faster and at higher revs, it kinda went away, but it's consistently makes noises at the abovementioned rpms. Also, the sound can be heard underneath the driver's side cabin. I went to my independent master technician, and he told me that it might be the idler pulleys (the car has like 3, I think). I looked at the pulleys and they looked a bit rough and for that matter, they've never been changed.

What do you think the diagnosis is? By the way, I did run a scan for error codes and nothing popped up.

Thanks,

Mo'

sosh

Nothing would show up on a scan with an issue like tensioner noise. Could be a correct diagnosis could also be incorrect. What interested me was your mention of your Independent "Master technician" Wonder who bestowed that title on him?? Maybe the god of independent technicians??

lkchris

Yes, forget the "master technician" stuff and look for recent dealership employment and training from Mercedes. He or she will need WIS access and a STAR machine, too. I wouldn't have motor oil changed on a recent Mercedes by anyone with any less.

CoupeLeicht600

Thanks guys for the input. How else would I know if it is the tensioner? Well, the reason I mentioned "master" is because he's worked at Benz in Germany for over 30 years, came to the States and worked here and became a "master technician" recognized by Mercedes. There are levels of technicians/mechanics. Alot of the guys at the dealerships are just computer savvy, plug the car in and read out the diagnosis. In addition, they only do what the computer tells them. Having the experience of a true master mechanic can help in prevention and not just the cure.

The only reason I mention this is because I've been to several Mercedes-Benz stealerships (e.g. Knauz Mercedes-Benz, Loeber Benz, and other ones) who have missed minor problems because the computer didn't "pick it up." Which, also costed me time and a extra few thousand dollars because of their incompetence. Therefore, I trust the experience and expertise of my master tech before I blindly go to the Benz dealer and throw money away to help them pay rent for their extravagant facilities.

Just FYI and my $0.98.

sosh

You would know if its the tensioner by proper diagnosis which in this case does not involve a computer or diagnostic machine. A stethascope or even a screw driver held to the tensioners when running would certainly give him a clue. As for your master tech, sounds experienced but today his experience from 30 years ago means nothing. Does he have a STAR system?? Access to WIS ?? Recent training on current models?? Most likely not. If I were you I would take your extravagant car to a dealer's extravagant facility for correct maintenence and preventative maintenence.