Ever since I bought my car over 2 years ago the belt / accessory system has made some very annoying noises. When I first start the car every so often (more lately) there is a "flapping" noise for 1 - 2 seconds as if the belt is jumping around. Other than that, there is a constant metallic sound with each revolution that sounds like a bad bearing. The problem is worse when it is cold out.

I've taken it to Sovereign Mercedes in Brooklyn (the worst business I have ever dealt with) 3 times to repair this same problem. First they said nothing was wrong - problem went away for 2 weeks simply because they removed and reinstalled the belt. Second time around they replaced the upper belt pulley (I believe this is what it's called?) the problem went away and again slowly came back over a period of 2 weeks. Next the idiots replaced the power steering pump - same deal, problem went away and came back after 2 weeks. Now my warranty is up so I am on my own.

Has anyone had a problem like this? I'm thinking it's gotta be the belt tensioner.

Video - http://www.youtube.com/watch?v=3fF5TfI1XVc
Not much to see, but listen to the audio. Had my hand over the microphone (doh!) until about half way in - so don't raise your volume unless you want to be jolted. The sound is definitely coming from the right side (when facing the engine).

I Really appreciate any help - this problem is annoying me to no end.

Edit: I just had another look and I can actually see the belt tensioner "pulsing" or moving in and out with each revolution. Is this normal?

 

If you have taken it to the dealer 3 times for this issue that still isn't resolved they are still liable. I know, I've been there. When my car's first transmission mount collapsed, I took it in under warranty but they didn't successfully fix it until 2 trips and 2 months after the warranty was over.

Aside from that, I am not familiar with what could cause the noise.. sorry.

 

acr - the tensioner should not pulse in and out. Sounds like a shot tensioner bearing. It sounds way gone - it's quite metallic if the recording is accurate. Almost a metallic squeak.That's typical I'm afraid. Do you have a 6 buck auto stethoscope?

 

My poor ears i should have read what you posted after the video lol. at first i thought what the hell is he compiling about sounds just like mine. then oh my god i would be freaked out if my car did that. as for the warranty they should still goodwill it because it is an ongoing issue. GL

 

Yes - mine sounds like finger over the mic

 

Thanks guys. Sorry about the volume!

I really hate taking the car to them and pulling teeth to get service, but I'll give it another try. Otherwise I guess I'm out $185 for a new tensioner.

 

No auto stethoscope. Would be a good tool to have....

 

 

Replace the belt tensioner.

 

Just a long shot but easy to check.....I noticed a slight noise starting and the belt moving in and out on the water pump pulley. It was the water pump starting to go. Lasted 165Kmiles. Grab the water pump pulley with your hand and rock it up and down to see if it moves. It shouldn't. Easy to replace and inexpensive if you buy it online.

 

The whole pulley on my pump feels sort of loose can move less than 1/2 or so mm in any direction. i felt the alternator pulley and it is rock solid is that what it should feel like or is the water pump always looser? BTW my car has about 141k on it with Water Pump, alternator and so on original.
Thanks btw how many miles are you up to now.

 

I just saw this. My car was making noise a while back too. My SA told me that this is a common problem and they will put the upgraded tensioner.

 

I'm at 165K miles. All the belt pulleys should have no play, or .025 -> .05 mm at the most. Follow Glyn's advice about a stethoscope if you're not sure where the noise comes from. A loose water pump bearing gets worse until it either seizes or allows all the fluid to escape through the clearance.
http://www.harborfreight.com/cpi/cta...emnumber=41966

 

Huh! - I got the price right!

 

thanks guess i will add it to my maintenance list

 

My car:
2008 C300 6spd MT sport
71K miles, daily driver and as of late, long road trips, about 800 miles roundtrip.
Serviced as per assyst by MB dealer.
Out of warranty, no extended. second owner.

Service B due now.

The story: I've had a couple bulbs out for the past couple months, the driver side eyelid, and the driver side lower brake light. I decided not to change myself because in the past, the dealer would do it out of courtesy. But last month before Service B was due, I noticed a cricket sound upon starting, but would go away after few minutes of idle. I just thought to myself: I will inquire when I take it to do Service B.

Today, I took it in to Service B and let them know that I was aware of the messages about the bulbs. The SA quoted me 55 in labor and bulbs. I declined. I also noted that I change my own oil since they don't use the 0-40 Mobil 1 I want. I also noted that my air filters are KN filters so I wouldn't need a change there.

That was 7am .

My SA called me at 12pm, told me it was almost done and wanted to inform me that they did just take a look at the two bulbs I mentioned and it was just the bulb so they went ahead and replaced them for me so I wouldn't have to go through the hassle and mentioned it was $11 a bulb. He also mentioned that they noticed the brake fluid was due for a flush because it was brown. I said if it could be done in time today, go ahead and do the flush. I then brought up my expectations of the Service B how it mentions they check the belts in the engine compartment: he acknowledged and said everything was examined and adjusted if needed but not replaced, and everything was ok. I then mentioned that I experienced the cricket noises lately upon start up. He replied that they did not hear anything when they started it up and did not see anything wrong when they worked on it. I said great , nothing to worry about.

I got off work and showed up at 4pm. He tells me: your car has some serious problems. He asked if its been in an accident. No it has not. He describes the wires being melted together and that's the reason why I had bad bulbs so they had to change them all. He then tells me that my belt tensioner needs replacing and the belt has been damaged and is even not on the tensioner's track. I asked if it was critical and he said yes. I asked if it was recommended not to drive, he said its not even drivable in its condition even if I wanted to. I got a couple of quotes from independent autohaus' and they both quoted me around 350. My SA says its 550 with a 10% break to help me out.

can I get some opinions here...

I did not mention that I got quotes today already and I even have one e-mailed to me for the belt tensioner and labor. I just told him that I couldn't afford that all today and if they could hold off on doing anything until tomorrow. I then reaffirmed with him "So, you're saying that the car cannot be driven at all if I did not replace the tensioner?" He replied "No, you cannot."

This is all fishy to me. I understand that with a great car, comes great costly maintenance. I believe that I have been a modest driver the time that I've had it. I've always done the necessary maintenance through the dealership even when in warranty and last Service A2 w/o warranty. I've only had one shop ever touch the car and it was for the X-Pipe and I watched them cut and weld under my car from start to finish.

My fear is that I forcibly ask for my car without the tensioner replacement but then they maliciously set it up to fail and boo hoo bad call on me. Legally, morally, and ethically this is wrong but if they did do that, would I have a leg to stand on in a legal battle.

I am thinking yes because I drove it to the dealership, they drove it into their garage, they drove it out to wash it, and now they are telling me this existing problem makes the car non-driveable under any circumstance? If anything were to have happened from when I dropped it off and when they serviced it, liability would fall on their laps, correct?

I'm just very frustrated and have been rubbed the wrong way when this same SA told me that brake replacement was due at 45k miles and it would be 800 for the rear set of brakes.

 

The story: I've had a couple bulbs out for the past couple months, the driver side eyelid, and the driver side lower brake light. I decided not to change myself as in the past dealer would do it out of courtesy. Last month before service b was due, I noticed a cricket sound upon starting, but would go away after few minutes of idle. I just thought to myself, I will inquire when I take it to service b.

 

This is the wrong forum, but I'd ask to get things out of the car and then demand to stay with it while they get the paperwork and I get ready to leave. That's all assuming they haven't already messed with it. It's sad you have to be like this but dealers simply cannot be trusted.

 

Thanks for your reply. I realized it was the wrong forum but have also posted to 204 forums...