erensf

Trying to figure out what's causing the high pitch noise in the video. It only happens at idle when the engine is warm, goes away at higher rpms. It seems like it's coming from one of the pulleys, but I'm not sure which one. Has anyone had a similar issue?

The car is a 2008 W204 C300 4Matic with 20k miles.

ModestStud

My 06 CLK350 does something similar very occasionally. That said, I don't know what it is.

99C43n843

mb tech here. common problem on 204's c-glass and glk. sounds like its the upper idler pulley making noise but its actually the tensioner. replace the belt and belt tensioner. problem solved.

khw8298

Replace upper idler pully

99C43n843

other techs at my shop including myself have made that mistake thinking its coming from the upper idler pulley but actually its the tensioner



Posted from Mbworld.org App for Android

kjb55

Good to know. I have the noise occasionally on my '10 and was going to change the idler pulley. Tensioner it is then...

ntrimm

Replace belt and belt tensioner. Will 100% fix your problem. I had the same issue

nnkfws333

This has been helpful but I had one more additional question. Has anyone used the Gates Belt Tensioner part #38319 ??? Trying to decide to either try this or go with the Ina part #2722000270. Just trying to see if anyone had problems with the Gates one or not or are they the same part.

nnkfws333

Well I got the Gates tensioner off of Amazon, , and it didn't work for my 2009 W204 C300 Sport 6 Speed Manual. On the back of the tensioner, where the shock absorber attaches, there is a screw that secures the shock absorber to the tensioner but the tensioner doesn't have threads for the screw. I wasn't going to put on the tensioner without the screw so I am just going to go for the oem part off of Autohausaz. Maybe some C300's don't have the shock absorber for the tensioner but I doubt it. Hope this helps someone in the future.

ticondo46

I'm also planning to change my belt in the not-too-distant future. However, I notice there is a plastic shroud in front of the pulleys. I will need to take this shroud off, but I'm not sure how exactly this thing is bolted onto the front of the engine. Is it something that requires some sort of special tool? I can hardly get a good look 'cause the gap between this shroud and the radiator is pretty tight.

nnkfws333

I didn't have to take off anything. Just the engine cover. BTW another edit! I promise last one. The OEM tensioner is just a rebranded Gates tensioner. As for the hole not being threaded, I just used the same screw and screwed it in. It threaded the tensioner for me. I had to buy an extra one though since I stripped the head of the the inverted hex. It had to be shipped from Germany and costs around $2...

I hope this helps someone.

snowmuch

Same noise happened to me recently when I tried to change my motor oil and accidental made a mess on the belt. I solved the problem by spry water on it while engine is warm and running.