WARNING: Check your Serpentine Belt Pulleys

Motodisiac

Moto Terrorist
I'm pretty religious about preventive maintenance. If I suspect something may fail, I try to replace it before it happens. This time I failed miserably, and I would like to share the experience.

Last Sunday I was supposed to help a friend with moving - one of the benefits of being the one with the van. Driving on the freeway shortly after I left, I felt slight thump, like I ran something over. Next thump was about the same, and the van slightly moved. I assumed it was the mud falling off the wheel wells - it gets there when I go to motocross tracks. This wasn't the case, as steering felt stiff. Red battery light confirmed my fear - the serpentine belt was off. I has similar issue with my Eurovan last year, so I knew right away.

After pulling off the freeway and pulling the hood open I noticed that the upper left pulley was completely missing - not possible to continue. Later I found blue pieces of the bearing in the engine bay - it overheated, seized and disintegrated.

I ended up replacing the remaining non grooved pulley and tensioner as a precaution - I do not want this to happen somewhere in the desert. The tensioner still felt OK but the smooth pulley was spinning freely with unpleasant dry noise.

The moral of the story - if you are still running original pulleys, loosen the belt (by using 17mm socket and inserting a pin in the tensioner) and spin your pulleys by hand. You will know right away if they are worn out - they should have no play and should not spin forever. Replace suspected ones and save yourself a lot of headache down the road. I guess this should be added to "must do list" along with transmission fluid replacement.
 

mean_in_green

>2,000,000m in MB vans
Lots written about pulleys and bearings failing. Another quick and easy check to make is to actually look down the front of the engine at idle: looking closely at the pulleys, are they rotating smoothly (almost 'motionless' in a sense) or are they dancing / wobbling about? The idler pulleys are the ones to pay close attention to.

Edit: - ones which dance may need replacement!
 
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talkinghorse43

Well-known member
I replaced the OEM ones before they failed, but the replacement tensioner ended up failing; probably because it was not equal in design to the original. So, even being proactive in maintenance can get you into trouble if you don't use the correct replacement parts.
 

mawsea

sprinter guru
I had a replacement tensioner pulley fail. It was aftermarket and I was happy to save a few bucks at the time but it only lasted a couple thousand miles.......lesson learned.
 
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jmoller99

Own a DAD ODB2 Unit.
When I swapped my water pump (lots of stuff to do to move the radiator out of the way), I also replaced the pulleys and tensioner (at approx 175,000 miles on the Sprinter). I found that while the old ones all freely spun, they felt dry and there was slight clicking noises on both separate pulleys and the pulley on the tensioner. I am glad I swapped them all out - I still have them.

Does anyone know a replacement part for the bearings used in these? I would like to replace the bearings and then keep the old parts as on the road spares.

Also keep in mind that if the clutch on the alternator is siezed up, it could damage the belt or the pulleys too.
 
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Motodisiac

Moto Terrorist
Low 175K. Before the failure there were no unusual noises. I'm just happy it didn't happen in the middle of nowhere.

As far as aftermarket parts go, as long as one sticks to good supplier, they are OK.

D.

Motodisiac? How many miles on your Sprinter?

--dick
 

talkinghorse43

Well-known member
As far as aftermarket parts go, as long as one sticks to good supplier, they are OK.
So, I bought a tensioner built by INA (brand of Schaeffler AG) in Germany from Europarts in San Diego and it broke in a little over a year in service. Sounds like a good pedigree to me. What's your definition of good?
 

chris118

Member
my tensioner pulley went out just outside of Carrrizo Plains at around 135k.
It was chirping for a few days before it failed.
 

Andy at Focallocal

Social Adventurer
My tensioner just died. I didn't have a choice of parts so I'm installing a 'Continental' replacement. Anyone know anything about their engine parts?

I assume they are just renting their brand rather than producing themselves, so what I'm actually installing is probably fairly obscure.
 

220629

Well-known member
My tensioner just died. I didn't have a choice of parts so I'm installing a 'Continental' replacement. ...
I have nothing specific, but that brand name shows up here in the States. Back in my VW days Continental was considered a good brand. Today? :idunno:

Is this what you have?

https://www.autozone.com/external-e...continental-idler-pulley-4046/821127_687570_0

If yes, the pulley design is a bit different from the OEM smooth type. The Continental dished pulley should encourage the belt to stay centered.

:cheers: vic
 

Andy at Focallocal

Social Adventurer
Thanks Vic. It's that brand but a slightly different part drop forge manufactured in Slovakia. This part: https://www.ebay.ch/itm/CONTITECH-K...RINTER-3-5-t-309-311-313-315CDI-/401916018924

I was able to remove the belt tensioner from underneath with this tool: http://imgur.com/gallery/F0MexvM

It needs both the length of handle, and length of the attachments to clear other engine parts and enable you to crank the tool. It's slow as I can only do 1/5th turns each time, but not too difficult to do without removing any other parts - just a bit boring.

Also others had issues with the caps on the other pulleys, as did I. I found its practically impossible with one screwdriver, but pops off pretty easily with two at the same time
 

UKmtrsp

Active member
Had mine go out just last week...17th...thread here: sprinter-source.com/forum/showthread.php?t=80300

I bought a kit from Europarts...and I am hoping that the parts are good quality. I have had no reason to think otherwise with the other parts that they have supplied for my van. I'm sure I could have done worse. They claim that this kit is what the dealers supply. The parts are also the same as the ones that failed on the van...that being said my van has almost 300k on it and I believe the tensioner and belt has been replaced twice before by the previous owner. Pretty good in my mind. There is no record of ever replacing the idlers or the alternator decoupler pulley. While I was in there I replaced the alternator pulley as well...it seemed fine, but good to have peace of mind. I also did a thorough check of the crank damper...no visible issues. Things are running smooth again, and I have a few older used parts that I can ad to my emergency kit.
 

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