mjr24

Any idea what this might be? It just started in the last few weeks....I took a video below (sounds like a film projector almost)...there are 2 belts in that area...I believe one is the serpentine belt....not sure what the other is. I can't find anything obvious upon doing a visual that would be causing the noise (sounds like something might be loose)? FWIW, I had the serpentine belt replaced back in April (had to get PS/ABC pump replaced and they said some fluid spilled on belt so they replaced it).


http://www.youtube.com/watch?v=bLZOI...ature=youtu.be

overZealous1

mechanics stethoscope can narrow it down pretty easy. just be carefull to not stick it in the running belt. haha. try to pry on or move pulleys with hand when not running.

abiazis

Have you had your belt tensioner replaced?

Supposedly, it has to be replaced at 50K for most Mercedes.....I replaced mione and the noise I was having disappeared.......

mjr24

abiazis....would it be normal for the mechanic to replace the tensioner at the same time they replaced the belt?

I'm not sure if they replaced it when they did the belt....

abiazis

What is the mileage of your car?

I don't think some mechanics realize that it has to be replaced at that interval. Look in your service manual and see when it is recommended.

I had to ask my shop to replace it.... They were not pro-active ...... It costs about $100 for the part...I had them do it with the belt change.... Hope that helps...

andy_meng1024

I might need to check mine, too. Any idea what the part number is?

andy_meng1024

On parts.com it shows SERPENTINE TENSIONER SL55 AMG for $200.40 is this the correct part?

abiazis

That is correct........the price sounds about right...

mjr24

Hey guys...what is that thing on the very left (of the three pulley type things).

I had a mechanic look at it today with a stethoscope and he said most of the noise is coming from that one on the very left. He said it was an idler roller....

However, is the idler roller AKA idler pulley? Or are those 2 different parts? Is this different than the serpentine pulley?

grane

Its the same repace all the cheap plastic pulleys, the belts, spinn the rest of the pulley by hand, make sure no noise, ensure torque and tension setting are correct, take a picture of the system before you take th belts off, make it easier, look at shardul's wonderful solutution envy!

Keep the ol;d belts and recycle the cheap plastic pulleys UNLESS they aren't noisy. Put them in your spare box along with the old belts in the trunk as insurance if you get stranded....

mjr24

Ha....cheap they aren't....from my research looks like the pulleys on left are the idler pulleys...$400 part from dealer as they don't sell the pulleys separately...

deliman

Its the inner Bearing on the 2 piece idler. Mine did the same thing. The good news is its an easy DIY. You just need to find the belt tension bolts. Upper one is easy. Lower one you need a socket and extension. Its kind of hidden. The bad news. Its an AMG only part. The pully for a SL500 looks like it would work but the diameter is different. Its a 2 piece kit that comes with a new bolt and spacers as well. As a Kit I got it for about $ 350.00 with my MBCA Card. Like 10% off. Once you have done the belts a few times you could do this repair in less than 5 minutes. Its that easy.
The dealer wanted about $ 650.00 for the job with parts. I am 100% this is what your hearing. The plastic inner pulley inner bearing is shot and the noise will get real loud when it just explodes like mine did. You will be so surprised how quiet your engine will be after this simple repair.

mjr24

Yep....I did some research after I posted this and I believe it's that. I think I'm going to just get the ASP pulleys (that are metal)...I don't know if I trust anyone to press new bearing in (and I certainly don't know anything about that).

deliman

The Inner Plastic Pulley and the outer metal groved pully are both in the kit with the spacers and the nut. I replaced mine a couple years ago and its been rock solid. Every 2003-2005 SL55 I have come across has had this issue by 50K miles. The new bearing seems to be of better quality. I looked at an expensive pully set too. Just not worth the expense. As far as just getting the Bearing it might work but the plastic pully looks to be part of the problem in itself. But for the $ 350.00 and the minimal labor its just easier to fix it and move on.