Can a bad tensioner cause the belt to keep slipping

46m3csl · 06-13-2019, 12:37 PM

So I made a post about how I replaced my serpentine belt because it was squealing and decided to replace the serpentine belt and the tensioner. But I drove the car maybe 50 miles and it shredded the belt. So I came home bought a new belt and drove around but now I can visual see that the belt has moved and will slip off again . I am thinking it's a bad belt tensioner and thus the belt keeps moving and slipping off.

I never had a problem before and all I changed was the serpentine belt and the tensioner.

Antetokounmpo · 06-13-2019, 01:42 PM

ughhhh yeah.

IllSic_Design · 06-13-2019, 03:32 PM

When changing the belt and tensioner all other pulleys/idlers should be changed also.

raptorman5174 · 06-18-2019, 08:08 AM

I'm having an issue where the crank pulley has a wobble in it and makes the belt move around and make noise when cold. Does anybody have a good DIY to replace the belt?
Do you have to remove the front inlet to do this job?

Bimmer_Engineer · 06-18-2019, 08:35 AM

You don’t have to remove the inlet...just loosen it. Removing the radiator fan makes it a lot easier...

Plus fix your crank pulley wobble...

austin.tillison · 06-18-2019, 08:43 AM

I shredded one belt years ago and then proceeded to just replace the belt and none of the pulleys or tensioners.

My replacement belt started showing signs of wear on the edges almost immediately but I still proceeded to drive the car for a few years, just keeping a close eye on the belt.

I finally put a new tensioner and belt on the car a few weeks ago and the belt is perfectly aligned once again with no unusual wear on either edge.

So with the car running, inspect the belt and each pulley very carefully and determine where it might be getting out of alignment or rubbing. Turns out my car just needed a new tensioner and that got it all straightened out for me.

good luck!

06-13-2019, 12:37 PM	#1
46m3csl Captain 121 Rep 774 Posts Drives: 335i Join Date: May 2010 Location: Rowland Heights iTrader: (0)	Can a bad tensioner cause the belt to keep slipping So I made a post about how I replaced my serpentine belt because it was squealing and decided to replace the serpentine belt and the tensioner. But I drove the car maybe 50 miles and it shredded the belt. So I came home bought a new belt and drove around but now I can visual see that the belt has moved and will slip off again . I am thinking it's a bad belt tensioner and thus the belt keeps moving and slipping off. I never had a problem before and all I changed was the serpentine belt and the tensioner.
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06-13-2019, 01:42 PM	#2
Antetokounmpo Brigadier General 1552 Rep 3,475 Posts Drives: E90 6MT FBO; '18 F150 Platinum Join Date: Jul 2013 Location: WI iTrader: (3) Garage List 2018 Ford F-150 Pla ... [0.00] 2008 BMW 335xi [0.00]	ughhhh yeah. __________________ 2008 335xi 6MT \| VRSF Catless DP \| VRSF 7" FMIC \| VRSF CP \| TIAL BOV \| DCI \| MHD 2+ BC Racing BR \| Stoptech 600 \| Firehawk Indy 500 255 Square \| Atric Altimax 225 Sq. 2018 F-150 Platinum 701A \| FX4 \| 3.5 EcoBeast
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06-13-2019, 03:32 PM	#3
IllSic_Design Colonel 2124 Rep 2,758 Posts Drives: 09 E92 335i Join Date: Jun 2016 Location: Northern California iTrader: (1)	When changing the belt and tensioner all other pulleys/idlers should be changed also.
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06-18-2019, 08:08 AM	#4
raptorman5174 Second Lieutenant 48 Rep 259 Posts Drives: 2007 E92 335i 6 speed Join Date: Jul 2008 Location: Central Jersey iTrader: (0)	I'm having an issue where the crank pulley has a wobble in it and makes the belt move around and make noise when cold. Does anybody have a good DIY to replace the belt? Do you have to remove the front inlet to do this job? __________________ 2007 e92 335i 6 speed FBO CPE Catted HiFlo DP's BMS SSK & JB4
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06-18-2019, 08:35 AM	#5
Bimmer_Engineer Lieutenant Colonel 1044 Rep 1,667 Posts Drives: 2007 335i Join Date: May 2018 Location: Louisiana iTrader: (0) Garage List 2008 Porsche Boxster [0.00] 2016 Mercedes Benz ... [0.00] 2007 BMW 335i [9.50]	You don’t have to remove the inlet...just loosen it. Removing the radiator fan makes it a lot easier... Plus fix your crank pulley wobble...
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06-18-2019, 08:43 AM	#6
austin.tillison Private 11 Rep 93 Posts Drives: 2006 BMW 325i Join Date: Aug 2015 Location: Alabama iTrader: (0) Garage List 2006 BMW 325i [0.00]	I shredded one belt years ago and then proceeded to just replace the belt and none of the pulleys or tensioners. My replacement belt started showing signs of wear on the edges almost immediately but I still proceeded to drive the car for a few years, just keeping a close eye on the belt. I finally put a new tensioner and belt on the car a few weeks ago and the belt is perfectly aligned once again with no unusual wear on either edge. So with the car running, inspect the belt and each pulley very carefully and determine where it might be getting out of alignment or rubbing. Turns out my car just needed a new tensioner and that got it all straightened out for me. good luck!
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