Dingleberry

Replaced the idler pulley (#4) and the grooved guide pulley (#6)

Car no longer sounds like a jet engine when RPM's are increasing.

positronicC32

Got a different, but similar, problem with my 2002 C32 (75K miles)

http://www.youtube.com/watch?v=LM48KqP8rGU

Any ideas?

positronicC32

Does it sound like this? Rattling when coming to a halt.

http://www.youtube.com/watch?v=LM48KqP8rGU

If you found a solution, please let me know.

Thanks

Dingleberry

It doesn't matter if the sound is coming from the idler pulley or not. At 75k, it's time to change at least pulley #4. I went ahead and changed pulley #6 because it was $30 and an extra 5 minutes of my time.

If that doesn't fix the sound, it's probably the supercharger pulley

positronicC32

I ordered an NSK OEM SC bearing and will see if that is a fix. I used a stethoscope to isolate the sound to the SC clutch/bearing, but it's not possible to recreate the sound in the video I posted whilst in Park and idling. I'll get my guy to look at ALL the pulleys when I install the bearing, just as a precaution. Thanks for the feedback.

Dingleberry

Change pulley #4 too

ttus

there seems to be tale-tell signs someting is wrong with @ least on of the pulleys when there is an occaionsal whining noise(in additon to the belt). This is very prevalent during cold nights or days and more apparent in temperatures below ~45F (and especially below 25F.

Bearings seems to whine more during cold winters or home air-conditioned garages? (bearing freeze or freezes). I have noticed these whining noises during the heavy summer months in southern cali and central TX. But then again, some may have waited a bit too long for attention to these pulleys where it doesn't matter if it is summer or winter?

positronicC32

...you were absolutely spot on. #4 was toast and the SC Pulley was on the way out. Thanks again!

splinter

Stethoscope observation revealed that the upper idler pulley (#6) was past due for renewal.
Sourced a suitable OEM replacement (#120 200 04 70) for less than $30.
Reused its existing bolt torqued to 20Nm with a dollop of #242 Loctite.

Of course that pulley and its mounting bracket must be removed in order to facilitate belt replacement.
Owing to an irrepressible ‘while you’re in there’ mindset, swapped in a fresh belt concurrently.
Surprisingly little wear after 50,000+ miles, although there was irrefutable evidence of the belt having lost a good fight against the supercharger’s drive pulley under the front cover.

tech notes:
My dampened 178mm evosport crank pulley was supplied with a different diameter idler pulley.
Gates’ 2910mm belt (vs. 2902mm OE) worked perfectly in this instance.
The tensioning pulley (#9) still has ~1/2” of additional travel before ultimately reaching its limit.
New setup runs almost as tight as a snare drum. ymmv

Chip Shams

Thank you for this I should probably get on this, just passed 112k

raf12690

Ok so I started hearing a weird whine during a cold startup that sounded similar to the issues in this thread. Went away and car seemed to pull/drive fine. Did the stethoscope check and the #4 idler was making a slight grinding noise like you said......ordered new part (green new part#). So i take out old idler and am about to place new o e when i noticed there was a slight deformity in the new idler pulley. Do you think I should put the old o e back on or should I place the new one?

raf12690

So the slight bend/dent is more so on the edge of only one side of the new pulley and isn't really much. Honestly I could probably put the new bearing in the old pulley which isn't thaaat bad. I'll probably put the old one back on and try and get another one. The part came in a legit mercedes benz box too. I would just hate to drive around in the other pulley knowing it can get worse. Anyways please let me know ASAP!

raf12690

Other side is perfectly round btw on the last pic.

Lenin

If you don't feel like returning it, bang it out a bit with a small hammer. But overall it minor, not ideal, but minor.

raf12690

Yeah I think I'm going to try that. This was honestly a temporary fix, as I plan on doing the PSK kit once I start start practicing. Dental school has been breaking my bank big time! Thanks for such a quick response!

NikolaosPsarros

I have one 2002 c32 amg w 50k , and my supercharger having this noise like in this video from YouTube , 3 mechanics 3 different opinions first to replace the all spcgr and pulleys for 4500$ second to change the inside BS part for 1300$ minimum and a third just waiting ,what did you think I can do ? car in excellent condition except this issue , no personal experience with garage and hand work at cars , thanks

c32used

I wanna say there is a thread on this type situation but not sure...as for opinion honestly don't want to steer you wrong way thus I'd say keep searching and asking questions if it sounds like this it may be something internal in SC a new pulley won't help that so maybe try to get cost out of it

clp86rom

First of all, if you need our help, you might want to take the time and post up your own video of the exact noise and issue/s.

Second of all, the reason why is because these cars are notorious for going through pulleys and their bearings and it makes it really hard to distinguish between all the possible variations of what could be wrong.

Expect only 50-75K miles from any of the following pulleys and their bearings front the diagram posted on the first page of this thread:
6 guide pulley
5 electromagnetic clutch
4 guide pulley
9 tensioning pulley

Lastly, nothing too expensive and hard to do yourself unless you take it to a shop where they tend to like to just replace everything vs just damaged goods.

Pansu

You can also change pulley bearings, drill/mill those "bolts" and take old bearing out, then new bearing and push it back together and use bolts&nuts to replace those drilled "bolts". New bearing costs about 10bucks.

jvakos

the c32 is in the shop today because the smaller sized idler pulley that comes with the ASP 178mm pulley kit went bad and caused my belt to come off.

anyone know the size of that smaller idler pulley that comes with the ASP 178mm pulley kit???

I searched and cant find it anywhere. the stock idler pulley is 90mm but doens't work with the ASP 178mm kit as the kit is designed to work with the stock sized belt. the idler pulley in the needswings PSK is larger 100mm and that seems like a good kit, so amstrongly considering getting one instead of trying to find a replacement for this smaller sized idler pulley that i cant seem to find. i called into ASP and left a message as nobody picked up.

johnng117

I'm using EC 178mm Pulley with the original idler for 4 years now, it's fine.

jvakos

so you are running the EC 178mm pulley, with your original MB OEM idler pulley (not this upgraded EC pulley, link below) and the stock sized belt?

my ASP 178mm pulley kit included smaller idler pulleys so the stock belt would work.

http://www.eurocharged.com/products/...pullies-detail

johnng117

I'm not using the EC idle pulley in the link.
I'm using the original as this is my second idle pulley, the belt is tiger but it does fit.

splinter

Who in his right mind writes like this guy?

fyi we're fixing up to do this same swap on another member's soon.

boohooramblers

Hahaha! Only you!
Hope you're doing well!