328i Belt Tensioner Defect?

fe1ixs · 09-25-2013, 08:41 AM

I just replaced my belt tensioner yesterday. mine was way off and the tech said can be anytime that the belt will completely off the pulley. BMW 328i E90 2008 with 65K miles. total cost $260. He said this is manufacturer issue. the replacement part is the same as the original so I should expect another replacement in the future. Btw, I highly recommended Brian autoworks at woodstock, GA. He is the BMW master tech with years of experience with global import BMW and the price is unbeatable.

Dyeraudio · 09-04-2014, 04:45 PM

I just left a local BMW repair shop for an oil change and the tech told me that my tensioner bolt was failing. Seems I caught it early because I have no sounds upon start up. You can visually see the belt "hanging" off just a tad bit. Better to fix sooner than later. When the sounds are there (squealing, whine) that is usually the bearing failing. Looking at $33 replaced. Better than a tow with a thrown belt.

morad · 09-05-2014, 09:41 AM

Yea me too, had the same issue with bolts and screws replaced..
cost around 500$ at dealership

TheSt|G · 09-05-2014, 10:59 AM

Is it just the bolt that is bending(which I can easily see as it is aluminum), or is the entire tensioner failing?

parabola · 09-06-2014, 07:25 PM

Mine got replaced at 34k miles.
You should really replace it, there is a possibility of catastrophic failure where belt gets sucked by harmonic balancer pulley and destroys the crankshaft seal, basically forcing the shredded belt into engine.

Dyeraudio · 09-09-2014, 02:30 PM

I just left my Indy shop after going in for the tensioner bolt. I need a new tensioner after all.... Vehicle is '08 328xi..... He swapped out 3 tensioners in his shop all with same issue....however all were used..... Having a new one installed tomorrow. Hopefully it fixes the issue. Belt hanging over pully lip about 1 mm.

Dyeraudio · 09-10-2014, 04:06 PM

Sure enough..... Tensioner was bad... All 3 he tried were toast....my original and 2 he had laying around his shop. $188 and 30 minutes later I'm down the road.....thank goodness for Bavarian Auto Werke in Orland Park, IL!

thomas88162 · 09-10-2014, 04:30 PM

Quote:

Originally Posted by TheSt|G

Is it just the bolt that is bending(which I can easily see as it is aluminum), or is the entire tensioner failing?

According to my dealership, it is the actual tensioner that bends over time. If you're going as far to remove the bolt, and have over 50,000 miles, might as well replace the tensioner anyway.

DaanBMW · 09-10-2014, 05:05 PM

hmm... I'm at close to 98k and the indy bmw shop just chked and told me I shouldn't do it, no signs of any problems... so many stories and no issues at close to 100k ??

TheSt|G · 09-11-2014, 07:54 AM

Quote:

Originally Posted by thomas88162

According to my dealership, it is the actual tensioner that bends over time. If you're going as far to remove the bolt, and have over 50,000 miles, might as well replace the tensioner anyway.

Oh I agree, I'm just wondering if we need to be concerned with other components in the area.

bimmertt · 10-23-2015, 05:56 PM

to those that have broken bolts, how are you extracting the rest of the bolt out? also, does the tensioner slide right out after you take the belt off or do you have to get the bolt out first?

bimmertt · 10-24-2015, 04:25 PM

Quote:

Originally Posted by bimmertt

to those that have broken bolts, how are you extracting the rest of the bolt out? also, does the tensioner slide right out after you take the belt off or do you have to get the bolt out first?

I've been trying to take the tensioner out for the past hour now. The bolt was already broken off. The tensioner slides out about an inch but won't come completely out. This seems like a common issue. Anyone have any tips on getting the tensioner out? This is exactly what I am dealing with right now:

Hops128i · 10-25-2015, 09:54 AM

Hope you figure this out, sounds like a PITA. this is making me think twice a preemptive DIY.

rjahl · 10-25-2015, 10:43 AM

Quote:

Originally Posted by bimmertt

Quote:

Originally Posted by bimmertt

to those that have broken bolts, how are you extracting the rest of the bolt out? also, does the tensioner slide right out after you take the belt off or do you have to get the bolt out first?

I've been trying to take the tensioner out for the past hour now. The bolt was already broken off. The tensioner slides out about an inch but won't come completely out. This seems like a common issue. Anyone have any tips on getting the tensioner out? This is exactly what I am dealing with right now:

I had the same problem two months ago. The head of the bolt is not completely broken off. I used a drimmel to cut a slot in the bolt. Then used a screwdriver to unscrew it. I took hours planing and researching and the fix took minutes. Remember the bolt is alloy and really easy to cut.

bimmertt · 10-25-2015, 11:19 AM

Quote:

Originally Posted by rjahl

I had the same problem two months ago. The head of the bolt is not completely broken off. I used a drimmel to cut a slot in the bolt. Then used a screwdriver to unscrew it. I took hours planing and researching and the fix took minutes. Remember the bolt is alloy and really easy to cut.

Thanks for the suggestion! I tried this but couldn't get a good angle on it with the dremel. I ended up taking a 7mm or 8mm socket with an extension, put pressure on the bolt and spun it counterclockwise. Of course this was after spending a few hours messing with it but when I saw it coming out slowly, I was so relieved.

Looks like we also share another issue...oil leak from the oil filter housing gasket?

Replacing the gasket is actually how I even noticed this issue. Only about half the belt was on the pulley. Only a matter of time before it would completely slip and leave me stranded. I'd definitely recommend replacing the tensioner preemptively.

rjahl · 10-25-2015, 02:12 PM

Quote:

Originally Posted by bimmertt

Thanks for the suggestion! I tried this but couldn't get a good angle on it with the dremel. I ended up taking a 7mm or 8mm socket with an extension, put pressure on the bolt and spun it counterclockwise. Of course this was after spending a few hours messing with it but when I saw it coming out slowly, I was so relieved.

Looks like we also share another issue...oil leak from the oil filter housing gasket?

Replacing the gasket is actually how I even noticed this issue. Only about half the belt was on the pulley. Only a matter of time before it would completely slip and leave me stranded. I'd definitely recommend replacing the tensioner preemptively.

I removed the fan shroud and could look through the structure while cutting. Like I said, it took planning. Failure would have required removing the radiator and most of the front of the car just to get a drill and "easy out" into the area.

Leaks hell, with the BMW I don't get worried about any of them until the first drop of oil hit garage floor. It's amazing how many leaks this car has had. I don't know if its the gasket materials or the synthetic lubes but it's had much more then it's share of oil leaks. I have a Lexus in the garage next to the BMW and you can not compare the reliability between them.

Eagle1oh7 · 10-25-2015, 02:40 PM

How many miles do some of you have? I peek under the hood now and then to check things out. Pics would be nice.

hassmaschine · 10-27-2015, 11:05 AM

I was paranoid about this on our E91, the service history said it needed to be done but the PO declined.

So I pull it out and the tensioner was 100% fine at over 100k miles. I replaced the belt but the original one was also in good condition, so I hung it in the garage as a spare. I guess I don't have to worry about it now but I didn't need to replace it. Oh well!

Looking at how it mounts, the bolt is mainly under tension, all the shear is taken by the block & body of the tensioner (a genius design, really). If the bolts are failing then I would have to think they were tightened incorrectly to begin with (too tight - prematurely yielding the bolt, which is why the head breaks off).

While aluminum has a lower yield strength than steel, if the bolt is of a sufficient diameter then it should be able to hold down the tensioner without issues. Maybe Hans and Franz had a bad bratwurst for lunch that day, or they didn't have their coffee and forgot to check the calibration of their torque wrenches in the morning..

Zajac1 · 10-27-2015, 03:54 PM

Quote:

Originally Posted by db2112

Had my car (2007 328i) serviced recently at a local independent BMW shop. The tech told me that my serpentine belt was slipping off due to a defective belt tensioner - the belt has about 1-2mm hanging over edge of top pulley. The tech says the belt tensioner pulley frame is bending and that this was a known defect but BMW won't recognize it. Only recourse is to replace the entire belt tensioner pulley and frame assembly.

I have searched and haven't found this discussed by anyone else. Is this really a known issue with these cars? Or is he maybe playing some kind of repair shop game here?

Same issue here : ) I'm glad my Bmw tech offer me a good deal. Belt tensioner + valve cover gasket, valvetronic and eccentric seal 100$ + parts. : )
btw. Any recommendations where I might buy this parts in good price ??

jvs1670 · 10-31-2015, 09:05 AM

Got mine here

https://www.oembimmerparts.com/BMW-E...7530314kit.htm

Zajac1 · 10-31-2015, 04:27 PM

Quote:

Originally Posted by jvs1670

Got mine here

https://www.oembimmerparts.com/BMW-E...7530314kit.htm

I bought my parts from getbmwparts.com not a kit, but only belt tensioner with bolt.

bacon33 · 08-05-2016, 02:50 AM

Have anyone had any problems after fixing/replacing tension bolt and/or pulley? I just had this happen to my car just hit 26K miles. What's strange is my wife's X5d, 2012 same year as mine had hers break off as well just a few months back. Luckily my dealership knows me very well and picked up the whole cost $700 as it damaged other parts. I'm over on time for my warranty so I would have been on the hook to pay. Doesn't help widest car needed rear brakes and rotors at the same time. Truly blessed and was taken care of.

09-25-2013, 08:41 AM	#23
fe1ixs Registered 0 Rep 1 Posts Drives: BMW 328i 2008 E90 Join Date: Sep 2013 Location: United States iTrader: (0)	belt tensioner I just replaced my belt tensioner yesterday. mine was way off and the tech said can be anytime that the belt will completely off the pulley. BMW 328i E90 2008 with 65K miles. total cost $260. He said this is manufacturer issue. the replacement part is the same as the original so I should expect another replacement in the future. Btw, I highly recommended Brian autoworks at woodstock, GA. He is the BMW master tech with years of experience with global import BMW and the price is unbeatable.
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09-04-2014, 04:45 PM	#24
Dyeraudio Second Lieutenant 110 Rep 217 Posts Drives: 2018 330i M Sport Join Date: Jun 2014 Location: Midwest iTrader: (1) Garage List 2018 BMW 330i xDrive [0.00]	I just left a local BMW repair shop for an oil change and the tech told me that my tensioner bolt was failing. Seems I caught it early because I have no sounds upon start up. You can visually see the belt "hanging" off just a tad bit. Better to fix sooner than later. When the sounds are there (squealing, whine) that is usually the bearing failing. Looking at $33 replaced. Better than a tow with a thrown belt.
	Appreciate 0 Quote

09-05-2014, 09:41 AM	#25
morad Registered 0 Rep 4 Posts Drives: 328xi Join Date: Sep 2014 Location: Boston iTrader: (0)	Yea me too, had the same issue with bolts and screws replaced.. cost around 500$ at dealership
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09-05-2014, 10:59 AM	#26
TheSt\|G Resident Tamed Racing Driver 298 Rep 4,697 Posts Drives: 911, 130is, E39 M5, E36 M3 Join Date: Mar 2008 Location: Outside Philly iTrader: (2)	Is it just the bolt that is bending(which I can easily see as it is aluminum), or is the entire tensioner failing? __________________ 2005 E46 M3 Interlagos/Cinnamon with Sunroof Delete
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09-06-2014, 07:25 PM	#27
parabola Lieutenant 30 Rep 447 Posts Drives: 2015 VW GTI Join Date: Nov 2013 Location: PA iTrader: (0)	Mine got replaced at 34k miles. You should really replace it, there is a possibility of catastrophic failure where belt gets sucked by harmonic balancer pulley and destroys the crankshaft seal, basically forcing the shredded belt into engine.
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09-09-2014, 02:30 PM	#28
Dyeraudio Second Lieutenant 110 Rep 217 Posts Drives: 2018 330i M Sport Join Date: Jun 2014 Location: Midwest iTrader: (1) Garage List 2018 BMW 330i xDrive [0.00]	I just left my Indy shop after going in for the tensioner bolt. I need a new tensioner after all.... Vehicle is '08 328xi..... He swapped out 3 tensioners in his shop all with same issue....however all were used..... Having a new one installed tomorrow. Hopefully it fixes the issue. Belt hanging over pully lip about 1 mm.
	Appreciate 0 Quote

09-10-2014, 04:06 PM	#29
Dyeraudio Second Lieutenant 110 Rep 217 Posts Drives: 2018 330i M Sport Join Date: Jun 2014 Location: Midwest iTrader: (1) Garage List 2018 BMW 330i xDrive [0.00]	Sure enough..... Tensioner was bad... All 3 he tried were toast....my original and 2 he had laying around his shop. $188 and 30 minutes later I'm down the road.....thank goodness for Bavarian Auto Werke in Orland Park, IL!
	Appreciate 0 Quote

09-10-2014, 05:05 PM	#31
DaanBMW Captain 84 Rep 777 Posts Drives: 2007 328i coupe Join Date: Jun 2011 Location: Portland, OR iTrader: (1)	hmm... I'm at close to 98k and the indy bmw shop just chked and told me I shouldn't do it, no signs of any problems... so many stories and no issues at close to 100k ?? __________________ 328i Sports Pkg, Michelin PSS on Staggered 18" OZ Ultraleggeras . BMS Powerbox. Cyba scoops + Rev motoring intake hose + charcoal delete. Wavetrac LSD . M3: subframe bushings + sways + control arms (fr & rr). Meyle rear toe arms. M3 diff fr bushings . BMW Perf: v2 springs + v1 dampers. Valeo SMFW+clutch. 034 MotorSport engine mounts . Short Shifter + Turner PU bearing + ZHP M weighted shift knob. CDV delete
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10-23-2015, 05:56 PM	#33
bimmertt Lieutenant Colonel 93 Rep 1,794 Posts Drives: 2007 e92 335i Join Date: Nov 2008 Location: Earth iTrader: (7)	to those that have broken bolts, how are you extracting the rest of the bolt out? also, does the tensioner slide right out after you take the belt off or do you have to get the bolt out first?
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10-25-2015, 09:54 AM	#35
Hops128i Captain 71 Rep 675 Posts Drives: 2010 128i, manual, sport pkg Join Date: Aug 2010 Location: Silver Spring, Maryland iTrader: (0)	Hope you figure this out, sounds like a PITA. this is making me think twice a preemptive DIY. __________________ 2010 128i manual, sport package, performance exhaust, Vorshlag camber plates, Bilstein B6 struts/shocks, 245/40/17 ZIII square on et 40 with rolled rear fenders.
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10-25-2015, 02:40 PM	#39
Eagle1oh7 Lieutenant Colonel 287 Rep 1,710 Posts Drives: '11 328i Sedan Join Date: Oct 2012 Location: Chula Vista CA iTrader: (0)	How many miles do some of you have? I peek under the hood now and then to check things out. Pics would be nice. __________________ DONE: Seibon CF Hood, M3 Rep, MSport rear w/DD CF Diffuser, M3 Rep Skirts, Seibon CSL trunklid, Forgestar F14 18s w/Michelin PSS, Eisenmann catback, AA Headers, BPC Stage 2, Charcoal Delete+revMotor+AFE Drop In filter FUTURE MODS: LED headlights, CF rooftop, M3 Suspension Conversion, Dinan CAI Mod
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10-27-2015, 11:05 AM	#40
hassmaschine Major General 3966 Rep 7,215 Posts Drives: "NBO" 330i Join Date: Jun 2014 Location: earth iTrader: (0)	I was paranoid about this on our E91, the service history said it needed to be done but the PO declined. So I pull it out and the tensioner was 100% fine at over 100k miles. I replaced the belt but the original one was also in good condition, so I hung it in the garage as a spare. I guess I don't have to worry about it now but I didn't need to replace it. Oh well! Looking at how it mounts, the bolt is mainly under tension, all the shear is taken by the block & body of the tensioner (a genius design, really). If the bolts are failing then I would have to think they were tightened incorrectly to begin with (too tight - prematurely yielding the bolt, which is why the head breaks off). While aluminum has a lower yield strength than steel, if the bolt is of a sufficient diameter then it should be able to hold down the tensioner without issues. Maybe Hans and Franz had a bad bratwurst for lunch that day, or they didn't have their coffee and forgot to check the calibration of their torque wrenches in the morning..
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10-31-2015, 09:05 AM	#42
jvs1670 Registered 0 Rep 2 Posts Drives: 2006 BMW 330i Join Date: Jun 2015 Location: Colorado USA iTrader: (0)	Got mine here https://www.oembimmerparts.com/BMW-E...7530314kit.htm
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08-05-2016, 02:50 AM	#44
bacon33 Private 9 Rep 75 Posts Drives: 335i Join Date: Mar 2013 Location: San Diego iTrader: (0) Garage List 2012 BMW 335i Dinan 3 [0.00]	Have anyone had any problems after fixing/replacing tension bolt and/or pulley? I just had this happen to my car just hit 26K miles. What's strange is my wife's X5d, 2012 same year as mine had hers break off as well just a few months back. Luckily my dealership knows me very well and picked up the whole cost $700 as it damaged other parts. I'm over on time for my warranty so I would have been on the hook to pay. Doesn't help widest car needed rear brakes and rotors at the same time. Truly blessed and was taken care of.
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