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Topic: Serpentine Belt shredded... Help? Reply to Thread
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  Topic Review (Newest First)
08-04-2018 11:00 PM
W210e55 So I recognize this thread/post is very old but I have a 2001 W210 e55 that started shredding belts weekly. Shredded 5 before I took it in to the Mercedes dealer for some help. This is my son's car and outside of this issue it has been a real trooper of car. It has 156K on the clock and it runs really well but this was annoying as hell and very inconvenient when it would shred many miles from the house. Anyway, I started into a long drown out process of replacing parts before I finally figured it out. At least I think I have as it's been two weeks and 150 miles since I have thrown a belt.

Parts replaced in order:

First belt: new belt

Second belt: new belt again

Third belt: new belt + tensioner + pulley (new style)

Fourth belt: new belt + fan clutch (sorta needed to be replaced anyway)

Fifth belt: new belt + alternator (old one full of melted rubber from all the previous thrown belts)

Sixth and current belt: new belt + A/C compressor & dryer + water pump (water pump was the culprit)

So after all that it turned out that the water pump had a very slow leak and was dripping on the belt. The water and coolant was causing the rubber get slick and walk back and forth on the hub of the fan clutch. They would get extremely hot weakening the belt and you know what comes next. The leak in the water pump was very slight but would increase once the revs would get up and the engine got to operating temperature. Let this be a service to anyone who's had the dreaded shredded belt situation on these cars. Start with checking to see if you have a very hard to detect leak that's dripping on your belt.
04-07-2012 02:26 PM
fabbrisd1 If you didn't replace the tensioner and the idler pulley at the same time - then my hat's off to you buddy for attitude.
04-07-2012 01:45 PM
Gray_Ghost Many thanks to the people that chimed in with help and advice. The tools arrived about 2:30 today. Finished up disassembly and reassembly in and hour and a half. New belt, fan, and clutch. Warmed it up to operating temperature, then took it on a rather spirited test drive (scaring my girlfriend's bro in the process, hehehe). My baby is back on the road and running about 10 degrees cooler as well. Again thank you! I couldn't have done it without your help.
04-04-2012 10:06 AM
SHAUNE55 OK I have the newer tensioner on this 2001 car so I can't help you with the torx size for the old one, I sold the one that had the old tensioner.
New one is 17mm and lift counter clockwise.
As I said though I've done the old ones with a ring spanner.
04-03-2012 06:17 PM
fabbrisd1 I have replaced idler wheel pulley - it's cheap buddy - since you are removing the fan the pulley is a easy job. Sure, pulling shroud clips and tilting works best to pull and reinstall the fan.

Go down to the W210 standard forum, same DIY, just a bit less front space to work with.

It would be foolish NOT to replace the idler pulley - since your old style tensioner shreded the belt (they sheds long way) - and your idler pulley already has serious cracks running fron the inner bearing race to alsmost the outside rim - it's ready to blow soon and with that you will be at square one over one $20/whatever part.

Yes - that idelr pully bolt is like a never ending long one for sure !
04-03-2012 05:11 PM
SHAUNE55 I will have a look in the morning at the size,
CC my mistake I've only ever encountered the older style tensioner, if you mean the top idler pulley I've only ever had to take the fan off to get the long bolt out.
04-03-2012 02:31 PM
Gray_Ghost Thanks guys. It's the older style with the Torx head on it. I've checked the pulleys though and all spin freely and no noise so I think the belt was just worn out as it seperated at the ribs. What size is that Torx bolt?
04-03-2012 01:39 PM
Check Codes
Originally Posted by Gray_Ghost View Post
I have the parts ordered. And I'm about the order the tool that fabbrisd1 linked to. My next question is how do I relieve Tension to install the belt? Special tool? I have a Serpentine Belt tool for my Ford vehicles but I doubt it would work.
It depends. If you have the old-style tensioner (with a threaded shaft extending through a nut on the pulley) you do it as Shaune55 indicated. If you have the newer style tensioner (and the suggestion you're getting is to replace it if you have the old one) there is a hex-head cast into the housing. Put a wrench (17mm? 19mm?) on it and push down to release tension.

Replacing the idler pulley is a giant PITA on that engine, you have to pull or at least angle the radiator out of it's support to clear the bolt.

Good luck.

04-03-2012 01:24 PM
SHAUNE55 It's just a small torx bolt but you can get away with a ring spanner if you don't have a female torx, just lift hard and it will release the tension . Watch your fingers!
04-03-2012 12:29 PM
Gray_Ghost I have the parts ordered. And I'm about the order the tool that fabbrisd1 linked to. My next question is how do I relieve Tension to install the belt? Special tool? I have a Serpentine Belt tool for my Ford vehicles but I doubt it would work.
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