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C63 Serpentine Belt Pulleys - Identification, Part Numbers
Shortly after I purchased this car used, the serpentine belt managed to skip grooves in the top left idler pulley, which caused the outside tooth/groove to rub against a coolant pipe's wire mesh, stripping the entire outside groove off the belt. I replaced the belt and made sure nothing looked damaged. It's been a little over 1.5 years now, and now I periodically get the classic "dude replace your belt" serpentine squeal on startup, maybe once every 2-3 weeks if that, and it goes away after a few moments. I've had a slight rattle/clack coming from the engine bay at low rpms, and there's a light yet persistent whirring sound heard if the engine is idling and you're standing next to it. I suspected it was something in the belt drive.
I've removed the belt and inspected it, it looks great, but it's not even 2 years old so that's to be expected. What I need help with now is clearly identifying which pulleys are idler pulleys and, if possible, what their part numbers are, or at least relevant links to order them. I wanted to try to consolidate this into one post/thread, because I've been Googling far too long this afternoon, and I still cannot clearly tell you which pulley is which, especially #7 on my photo below, which doesn't even show up on most of the "C63 Diagrams" I've found:
A few MB Parts sites have diagrams for the three upper pulleys and they aren't too bad at $30-$40 each, but they are usually just labeled a generic "Pulley" and I can't find one that points to #7. So, if you guys could be so helpful as to let me know which numbers are which (idle/guide/shear pulley, or upper/lower, etc.), I'll update this post accordingly, and maybe it'll come in handy for others searching in the future:
Idler Pulley at Water Pump, Grooved - MFG # 1562020619 - Link to ECS Tuning
Idler Pulley at Water Pump, Smooth - MFG # 1562020819 - Link to ECS Tuning
Had something similar happen to me recently but it was the alternator pulley and it took out a lot of wiring with it, still in the shop waiting on parts
I've seen some billet pulley kits but not sure those are really worth the price
Yeah, I've read some horror stories on others snapping a belt and it taking down half the bay with it. Sorry to hear yours. I don't know what made it jump in the first place - the wire mesh was a millimeter or so away from the belt, and it happened when I cold started, so maybe there was enough slack from one of the pulleys that it made contact. After I replaced it, I crimped that mesh down to give it some more room.
Yeah, I've read some horror stories on others snapping a belt and it taking down half the bay with it. Sorry to hear yours. I don't know what made it jump in the first place - the wire mesh was a millimeter or so away from the belt, and it happened when I cold started, so maybe there was enough slack from one of the pulleys that it made contact. After I replaced it, I crimped that mesh down to give it some more room.
I hope yours was under warranty!
Extended warranty is covering it, so far replaced the belt, alternator and some wiring it sliced turns out it blew a resistor in the ecu too so the ecu is being ordered too...this would be a massive expensive if warranty didn't cover it.
Guess I just have to check regularly now, I had heard some belt noise on startup but it sounded like it was normal .
Be interested to see the pulley schematic for future reference
1. Idler
2. Idler
3. Idler
4. Alternator
5. Water pump
6. Crank
7. Idler
8. Belt tensioner
9. AC pump
10. Power steering
I think that is right?
Mine is making a bit of a whirling noise that comes and goes at idle too. I can't locate which pulley it is yet. It hasn't been doing it for a week or so now. To replace the billet ones is $$ so I'm trying to locate the noisy one.
2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
Here is a belt wrap picture. Idler #7 is not shown in this pic. It must not have been installed on the older engines and was retrofitted at some point. Perhaps to reduce harmonious vibrations occurring in the belt as it passed between the crank pulley and the A/C pulley.
Thanks Mort. I had seen that image from another thread, and when I saw #7 missing, I almost had a minor freak out. But I found, like, two other photos out of dozens that had it installed so I'm assuming the original planned engine didn't have it and it came later. Ironically, that's the pulley that seems to be the most worn out on mine, and I'm at 47k miles.
I was hoping we could get a little more detail on the pulley names/codes, though, as just 'pulley' makes it difficult to know which one to order. I see some sites saying "upper" pulley, some just "idler" pulley, etc. Maybe this just a case of a part having different names to describe it.
First I wanted to thank you for posting links to our site!
I received an email from our sales department regarding this, and #7 is the same pulley as #1. This pulley is used in both locations on your vehicle (at the water pump, and between the crank pulley and the refrigerant compressor). From EPC there is a split on this pulley in location #7, Up to engine 60057841 (up to date 11/02/2009) the part number used is 1562020619, which is a grooved pulley. From engine 60057842 (from date 11/02/2009) the part number used is 1562020819, which is a smooth pulley. I am putting the part numbers and photos of each below for reference.
David, thank you so much for posting that information. That clears a lot up. Now I understand why some MB Parts departments would have two part numbers for that same pulley, sheave vs guide, etc. Interesting that they changed the design to smooth in 2009. I have an earlier engine, so I'll be grabbing those grooved pulleys from you guys.
Looks like I need to get myself a subscription to EPC.
05-23-2015, 07:37 PM
