CQHall

Hi, all.

Recently, I was on a errand and while outside of the running car, I heard a, "tick-tick-tick-tick", from the engine bay. Figured it could wait until I got home...nope. Accessory belt broke and thew the supercharger belt and unraveled themselves and wrapped around the crank pulley.

The damage wasn't as bad as I expected after having steel cables whipping around in there at hundreds of RPMs. I removed the fan shroud in order to make some room to unwind everything. The only damage that I can find (knock wood) are the two air intake tubes that got shredded a bit. The serpentine belt wasn't OEM (it was Mitsuboshi (with an "o") brand) and I have no idea how long it had been in service:





My car is a 2003 and has around 140K miles. Bone stock (besides wheels, front lip, and wing).

A few questions:

• What else should I replace while I'm in there?
• Should I go for OEM or aftermarket belts?
  • OEM Accessory Belt: $42
  • OEM Serpentine Belt: $46
• The tensioner pulley to the left of the supercharger has (literally) 1mm of play.
  • Should I replace it now or wait until the play is more pronounced?
  • If so, OEM ($475) or aftermarket?
• The fan is OK. I broke a clip on the right that holds tubes by tugging too hard.
  • Is the fan something that I should replace now or wait for if/when it fails?
  • OEM Fan and Shroud: $630
  • OEM Shroud alone: $185

Any thoughts would be appreciated. I'd rather ask now than to find out later that it would have been a great opportunity to do something while I'm in there.

Thanks!

Pic because, why not:

CQHall

I have the replacement parts in hand and not only are the belts OEM Mercedes belts, they are marked "AMG", which is unexpected and cool.

CQHall

Sooooo...I think I found the culprit.

I think this plastic pulley broke:



I found these bits in the engine bay when I was cleaning it out:



This may explain the "tick-tick-tick-tick" sound that I heard before all hell broke loose. Why the hell would MB make this out of plastic? I'm sure there is a reason as the other pulleys are metal.

Should I replace with OEM ($700...and probably still plastic) or aftermarket?

CQHall

To sort of answer my own question: "Why the hell would MB make this out of plastic?"

I got to thinking while doing dishes, MB engineers had a really good reason for making this plastic when the others are metal, and I just don't know what it is. My guess is that it might have something to do with two metal wheels spinning at several thousand RPM next to each other while exposed to rubber, heat, salt, water, etc...

Z55AMG

Hey CQhall im in the exact same situation, belt got shredded off because the plastic side of the double idler pulley broke, i was wondering if u ordered an oem one or aftermarket pulley and what kind of belt did u get. right now im looking at a $150 pulley from URO and a belt for around $30 from Gates, stealership told me the oem pulley is $800+ so im definitely probably gonna go aftermarket

CQHall

I ordered this pulley from FCPEuro: https://www.fcpeuro.com/products/mer...ley-1132020419

It's $289 now. Not sure how much it was when I bought it.

I got the OEM AMG belts (made by Gates, BTW) from my local dealership. If you order from MBUSA you can get a really good price and pick it up at your local dealer or they'll ship it to the dealer (using their normal network) then someone at the dealership will box it up and mail it to you. It's an extra step that's not worth it to me because I'd rather have it two days earlier. Sometimes the prices here are actually cheaper than FCP Euro and ECS Tuning, believe it or not. FCP and ECS will match MBUSA prices if they are lower.

https://mbparts.mbusa.com

nd-photo.nl

Just go aftermarket with billet pullies from a reputable brand, at this point they have been tried & tested. I upgraded them myself not too long ago

I went with Fabtech



Also replaced the tensioner with a new tensioner which also has a steel pulley instead of a plastic one



Was also due for a replacement


More pics in my build thread: https://mbworld.org/forums/c219/8443...ld-thread.html

CQHall

I really think there was a reason that MB engineers put a plastic pulley next to the metal one (as opposed to two metal ones). My guess is that there may be some magnetic or static charge going on. I have no idea, but I'm sure that there is a reason.

nd-photo.nl

Design choices should be made public after x time, then we wouldn't have to be guessing why they did this in the first place

Or would be awesome if we would have AMG engineers who created this beast on this forum

SICAMG

ND I agree. I have soooooo many questions for them !!!! LOL