The symptom is crazy loud engine noise. My trustworthy independent mechanic has narrowed it down to the supercharger pulley. Indeed, I can hear it when he points to it with the engine cover off.

He says the pulley is shot and the only real fix is to replace it. But he admits that, while he does only Mercedes, he's not a supercharger expert.

The problem is that I understand the part alone runs about $1,500.

Is replacement the most practical option?

Thanks in advance!

It's $1,500 for the entire electromagnetic clutch assembly with new belt pulley. Your problem isn't the clutch. The pulley bearing needs to be replaced. It cost $50 dollars for the bearing. Use the search this is discussed often...

Thanks, have indeed searched and it seems you are one of our key experts on this issue! Thanks for your contributions - wish I was as handy.

Is this one of the threads you are referring to? Appeared like it was the supercharger pulley bearing like you predicted?

Do you believe that's the only thing it could be?

https://mbworld.org/forums/c32-amg-c...eo-help-3.html

Hold up, Glasgow Gold.

If it’s more than $200 to replace that noisy pulley’s bearing, you’ll forever be banished to OT. :D
Our OE IHI/NSK supercharger bearing is PN 32BD45DUM. Less than $50 from various vendors.

Recently replaced my tired supercharger pulley bearing and idler pulley.
Almost like rolling back its odometer 80,000 miles.

reference 1 & 2

Ha ha, thanks my friend - I am much "better" at OT than at the other forums! Have you taken the Sheen/Gaddafi quiz yet?!

Much appreciate these helpful suggestions.

I'm willing to bet money that's the issue. I started that thread and both my brother and I thought at first it was a bad super charger, then a bad pulley then it turned out to be the bearing just like everyone else. It's pretty easy to replace. (I'm a software guy) So if I can do it anyone can.

This is the bearing you need: http://cgi.ebay.com/ebaymotors/OEM-M...Q5fAccessories

As well as the video posted in my thread, have a look at his one:

http://www.youtube.com/watch?v=LAcmJRZrpBo

You can see in the video he has that same annoying noise. Once you change the bearings it's smooth sailing.

Hey, I heard that's illegal??

I'd say bearing(s) too. Do YOU have a crank pulley like ASP or LET ? If so just get a PSK (Pulley Saver Kit) from Needswings. Its a great kit for crank pulley modded cars.

The PSK kit is great for peace of mind, but will do nothing for a noisy (i.e. shot) S/C pulley bearing. Just making sure the OP understands.

+1, NOTE that I said if YOU have a crank pulley you NEED the PSK. OP , do you have a crank or Code 3 SC pulley??

The SC pulley bearing is another issue, BUT while you're at it (and if you have a crank pulley), get the PSK.

If you have a stock OEM pulley(non-Code 3), a good source for the NSK bearing for $49.00 is http://www.hpashop.com/product.sc?pr...&categoryId=58

Also try bearingsdirect.com

There's also a DIY at the end of this MB world thread: Replaced SC Clutch bearing last night ~ pics/video at : https://mbworld.org/forums/c32-amg-c...ics-video.html
and a more recent one:
https://mbworld.org/forums/c32-amg-c...ing-video.html

If you have a bearing press and the bearing, this is something you can do yourself. DO NOT Hammer on the bearing as it will damage the new bearing while putting it in. Thats what presses are for. Any machine shop can put the new one in for very cheap.

Thank you all for the great suggestions and links.

Newz, everything in the engine is stock OEM. And I'm not mechanical at all. So, now I will try to find a mechanic who will just do the S/C pulley bearing. My usual guy might even be willing to try it.

Do you guys think this needs to be fixed urgently? That is, am I right in believing that all hell will break loose in my engine if I don't get that bearing replaced ASAP?

I will try to keep the thread updated to let you know how the adventure goes! I love the car and want to keep it for a long time.

You should pay NO more than $100 US including $50.00 Part to do this!! Its about a 15-30 minute job IF the car is cold (left over night) since you want the pulley cold to remove it. You can even tap out the bearing and then press in the new one.

The challenge is finding a guy interested in doing one offs in this way. Just talked to my usual guy and he says he just doesn't have the tools (?) to pull this off.

Found another mechanic who has a good reputation here and he is willing to try, but seems kind of nervous. Says he too usually just replaces the whole supercharger pulley because of poor parts availability, equipment, etc. But, he is willing to do whatever with the part I supply "with no guarantee that it will work." Fine.

So, I have ordered the suggested part from ebay and will contact the mechanic again when it comes in.

Wish me luck on my noob cheap repair adventure!

http://cgi.ebay.com/ebaymotors/ws/eB...#ht_684wt_1167

I'm guessing I'm too late in posting up the link to this thread. I got my replacement bearing from Doom at a great price. He is a trustworthy member and seller.
https://mbworld.org/forums/c32-amg-c...fire-str6.html

+1 to Doom and I also think that ML500K had em too??

She sounds like she's gonna blowwww!

http://www.youtube.com/watch?v=vcRBCYfIw9E

Looks like our Cs are related, heh.

http://www.youtube.com/watch?v=5D78HhG9l9o

I suggest not driving her anymore until the bearing is replaced...

I'm trying not to drive her much, but I don't have much choice. The new bearing is on its way soon, along with the infamous idler pulley and some SC oil. She's been making these noises since Nov or Dec last year, though... would it work to drive while mostly staying out of boost?

Actually, no... Your best option is to try and maintain at least 1PSI of boost...

Could be why she's making so much noise now

The bearing is there for free spin of the front belt drive pulley. Once the electromagnetic clutch locks the bearing is no longer spinning.

Aha, gotcha. That makes a lot more sense now. So... drive like an ******* until I get the new bearing put in? Aye, cap'n!

Ugh, I know that sound!

My "surgery" is scheduled for Monday and I will report back. Shipping of the part from the ebay site linked above was very fast.

Yup that's the bearing no doubt. You car will sound saaweet after the bearing change

So, the surgery was completed today and overall it's good news.

The supercharger pulley bearing was indeed shot. You can see the wear/burn marks in the last picture below. It was replaced with the NSK bearing purchased via ebay and the link above.

This substantially reduced the noise, but there were other issues. The grooved idler pulley was also making alot of noise so, as that is a cheap part readily available from the dealer, the mechanic also changed that. The smooth idler pulley was dry so the grease was repacked. Then, in the course of all of the testing, the check engine light went on, the car went into limp mode and a faulty accelerator pedal was replaced! Never a dull moment.

So, as the before and after videos show, the car does sound better. More importantly, now my mechanic feels that remaining noise is just annoying - not something that's going to cause bits to start spraying around the engine. He feels the remaining noise is attributable to the supercharger clutch flex plate.

Thank you all for your helpful advice in getting right to the bad bearing diagnosis. Saved me lots of time, hassle and money. Dinner and drinks on me next time you are in the Bay Area (ok, ok, feel free to insert your favorite SF-bashing joke here)!




Before:
http://www.youtube.com/watch?v=vcRBCYfIw9E

After:
http://www.youtube.com/watch?v=QPEHIo-AR8o