Belt started shredding

cahme · 07-11-2018, 10:36 PM

Was driving my 2011 N55 335 home from work and heard a bit of an odd ticking sound, especially around 1800 RPM. When I checked I noticed my belt looked a little skinny and had something flapping during every rotation. See pics attached.

My belt was shredding and have a couple thoughts:
a) I'm not sure if these partially shredded belts get past the front seal, or if it's just when the belt brakes? I wonder if changing the oil and checking for bits is enough? This really scares me, yet I really don't want to drop the pan.
b) What could have caused this? There's no oil from OFHG or anywhere else ..

I definitely could be looking at a much worse problem!

Belt is a Continental brand and changed out about 40k mi and 2 1/2 years ago. Tensionor and idler pulley were changed then as well. All pulleys spin smoothly and I don't see what could be an issue. It was starting to get dark when I was digging in, so I called it a night. I'm not driving it until I'm confident it's good to go.

Here are some pics comparing it to the previous belt @ correct width as well as what's still on my splash shield. I need to go back and see what's up with string that is hanging. The side that is coming apart is the side closest to the engine, if that helps.

e90yyc · 07-11-2018, 10:44 PM

Based on that I kind of doubt any belt made it past your front main seal.

In order for the belt to be ingested, it would probably have to wrap around the crank first, which would then cause it to essentially ‘screw’ its way through the seal. If I was an eng I’m sure there would be a better term for this, but hopefully it makes sense.

No idea what might have caused your failure, but I would *think* you’re in the clear for belt ingestion.

Also, thank you for the good pics!

tlow98 · 07-11-2018, 11:00 PM

Could look for bits in your oil via a change, but I’m guessing you’re fine.

Great catch!

Bimmer Pleaser · 07-12-2018, 05:35 AM

Belt can absolutely get sucked into the engine, I personally have heard of multiple cases. The main culprit as you probably know is a leaking OFHG which causes the belt to get dislodged and wrapped around the shaft. Hopefully it’s not the case with yours but the only way to be sure is drop the oil pan as far as I know.

mecheng77 · 07-12-2018, 05:48 AM

Wow surprised it went so early. I’ve had belts easily last 250k on other cars. Maybe there is a sharp burr somewhere

tpknet · 07-12-2018, 01:35 PM

I am dealing with this exact problem right now. Some things you can try before you pull the oil pan to see if you have a problem:

Unwind and an all pieces of belt from the crankshaft. If you do this carefully and look closely you should find some of it that goes in past the seal if it has. It can also destroy that front seal which should be obvious if it is really bad. On mine there was no rubber left on the front crank seal, all that was left was the steel support ring that is supposed to be an integral part of the seal.

Drain the oil through a paint filter. You can find these at any paint store like Sherwin Williams or Benjamin Moore. I found tiny pieces of rubber in the oil. really tiny, so tiny they made it past the screen in the oil pickup tube. However, you should be able to see them. Maybe some kevlar fuzz as well.

Cut the oil filter and check it for tiny rubber pieces, I found them in my filter.

If all of that looks OK you could take a chance on driving it. The biggest problem from the belt getting shredded in the engine by the timing chain seems to be loss of oil pressure as it plugs the oil intake screen.

The chance you are taking by driving it further if there is enough in there to cause problems and you don't detect it by the above methods is that when mine got plugged, somehow those tiny bits of rubber made it past the filter. I found them in the oil galleys in the crankshaft and on the rod bearings when I pulled the rod bearings. I think this last bit is why even after these engines are "repaired" the engines burn up after 6 months.

I am not sure what to do with mine now that I found the rubber on the rod bearings.

Good luck,
I hope yours didn't make it as far as mine did.

Please keep your post updated with what you find out.

IllSic_Design · 07-12-2018, 01:52 PM

Check the power steering pump pulley, they can crack/break apart and rip the belt apart. I just had to change a guy's out after he shredded a belt and his pulley was not even hitting the subframe, it just started to disintegrate.

mecheng77 · 07-12-2018, 02:26 PM

Quote:

Originally Posted by IllSic_Design

Check the power steering pump pulley, they can crack/break apart and rip the belt apart. I just had to change a guy's out after he shredded a belt and his pulley was not even hitting the subframe, it just started to disintegrate.

Is that pulley plastic?

IllSic_Design · 07-12-2018, 02:34 PM

Quote:

Originally Posted by mecheng77

Is that pulley plastic?

Yes it is. The guy ended up getting an aluminum one from ECS and I installed that for him, shouldn't have anymore issues like that.

e90yyc · 07-12-2018, 03:35 PM

I've also heard of bad A/C pulleys as well. Worth checking.

Rube · 07-12-2018, 05:06 PM

Quote:

Originally Posted by IllSic_Design

Check the power steering pump pulley, they can crack/break apart and rip the belt apart. I just had to change a guy's out after he shredded a belt and his pulley was not even hitting the subframe, it just started to disintegrate.

+1 check the pulley. On my 07 E92 I noticed some chafe marks on the belt from what looked like contact with the subframe, so When I replaced it I made it a point to check the power steering pulley. Sure enough, the rear of the pulley was all busted up from hitting the subframe even though it seemed like I had plenty of clearance between the pulley and the sub frame. Luckily I caught it early. I also changed out both motor mounts and sure enough the driver mount was in bad shape.

cahme · 07-12-2018, 10:13 PM

Thanks for the suggestions and comments ... Good stuff. I didn't get a chance to look at it at all today.

pknet, did you catch it before the belt broke? I live the paint filter idea as I was thinking I'd be able to see any bits just 8n the pan. Will also cut the filter as well to check.

The pulley info is also great. I was focused on checking them quickly for bearing wear but didn't think about them being plastic. I had tried to check for subframe contact, but need better light for that.

I didn't have any belt wrapped around the crank and he more I think about it, I don't think I shreaded enough belt substance to have forced it through the seal. I still want to take any reasonable precaution, though

I'll keep y'all posted as I make progress.

mweisdorfer · 07-13-2018, 06:37 AM

Quote:

Originally Posted by cahme

Thanks for the suggestions and comments ... Good stuff. I didn't get a chance to look at it at all today.

pknet, did you catch it before the belt broke? I live the paint filter idea as I was thinking I'd be able to see any bits just 8n the pan. Will also cut the filter as well to check.

The pulley info is also great. I was focused on checking them quickly for bearing wear but didn't think about them being plastic. I had tried to check for subframe contact, but need better light for that.

I didn't have any belt wrapped around the crank and he more I think about it, I don't think I shreaded enough belt substance to have forced it through the seal. I still want to take any reasonable precaution, though

I'll keep y'all posted as I make progress.

Three things cause the serpentine belt to shred like that.

1) bad motor mounts
2) OFHG starts to leak on the belt
3) front crank seal starts to leak on the belt

If you are over 125,000 miles on OEM motor mounts, and the roads you drive on are typical mid-west pot hole ridden roads, the motor mounts are on borrowed time.

If you are over 90,000 miles on the OEM OFHG, you again are on borrowed time with this particular gasket.

Front crank seals can be a b@tch to seal back up. I am currently in a saga with mine. I have changed it twice and it's still leaking. I'll be ordering gasket no 3 today. The tool and BMW sealant are not cheap.

I would go to FCP and get a lifetime warranty on the seal and sealant. They don't list the primer on their website. I'm calling them today to see if I can order the primer through them and subsequently get a lifetime warranty on that too. It's only $12.00 for the primer, but $12.00 is $12.00.

You'll need a syringe, needle & plunger. ECS tuning sells a front crank seal kit with all the items needed, but no warranty. BAV Auto sells a syringe kit for $8.00.

Sealant - loctite 193140 (83190439030) - $50.00

Primer - loctite 171000 (83197515683) - $12-15.00

Crankshaft Seal - 11117547842 (BMW e60, 82, 90)

New belt - CRP - 7K1855 (for an N54) / $18-20.00

BMW Needle for Sealant - 83192345991

Front seal tool or front & rear seal tool.

CTA 7643 gives you the tools for the front & the rear

Remember the RMS (rear main seal) is a "known" seal to go on an e90 about every 75-90,000 miles.

You can buy the front tools only for around $200-225.00. The RMS tool is about $100-125.00 there of, if you buy them separately.

eEuroparts rents the tools for the front crank seal.

https://m.eeuroparts.com/Parts/43359...19220PLUSRENT/

cahme · 07-13-2018, 07:14 AM

Well, the PS Pulley votes pulled through here. Whether or not it was caused by motor mounts are not is yet to be determined, but I'll likely change them out as well. I'll report back what I find from a hitting the subframe standpoint.

Here's a pic of the pulley:

cahme · 07-13-2018, 09:00 AM

Quote:

Originally Posted by mweisdorfer

Three things cause the serpentine belt to shred like that.

1) bad motor mounts
2) OFHG starts to leak on the belt
3) front crank seal starts to leak on the belt

Looks like #1 is likely here, but I am curious, for #2 or #3, wouldn't it cause the belt to slip off and break? In my case the belt remained in place still functioning.

Thanks for the detailed info.

mweisdorfer · 07-13-2018, 09:59 AM

Quote:

Originally Posted by cahme

Well, the PS Pulley votes pulled through here. Whether or not it was caused by motor mounts are not is yet to be determined, but I'll likely change them out as well. I'll report back what I find from a hitting the subframe standpoint.

Here's a pic of the pulley:

It's a known fact that the n54/55 motor mounts are not as stiff as they should be, and over the long haul, as they weaken due to milage, the power steering pulley hits the subframe when you hit a bump etc.

The only way to counter this is to get better than OEM motor mounts. For a long time, people were getting 335is mounts. However, in the last 6 months or so, the price of the 335is mount has gone to $600.00 plus dollars.

So, this forces people to look elsewhere for motor mounts.

Rube · 07-13-2018, 07:17 PM

Quote:

Originally Posted by mweisdorfer

It's a known fact that the n54/55 motor mounts are not as stiff as they should be, and over the long haul, as they weaken due to milage, the power steering pulley hits the subframe when you hit a bump etc.

The only way to counter this is to get better than OEM motor mounts. For a long time, people were getting 335is mounts. However, in the last 6 months or so, the price of the 335is mount has gone to $600.00 plus dollars.

So, this forces people to look elsewhere for motor mounts.

A couple of washers under the driver side mount would give a bit more clearance I think. I was going to try it when my mounts were replaced but never had a chance to do it.

nsjames · 07-13-2018, 08:47 PM

Quote:

Originally Posted by cahme

Looks like #1 is likely here, but I am curious, for #2 or #3, wouldn't it cause the belt to slip off and break? In my case the belt remained in place still functioning.

Thanks for the detailed info.

the oil contamination will eventually soften up the rubber and then the belt will shred.

cahme · 07-14-2018, 05:58 PM

Quote:

Originally Posted by IllSic_Design

Yes it is. The guy ended up getting an aluminum one from ECS and I installed that for him, shouldn't have anymore issues like that.

It's listed to be an N54 pulley and the N55 cars aren't listed as a bit.
Do you know that it will, or what the difference between N54 and N55 PS pulleys are?

IllSic_Design · 07-16-2018, 09:55 AM

Quote:

Originally Posted by cahme

It's listed to be an N54 pulley and the N55 cars aren't listed as a bit.
Do you know that it will, or what the difference between N54 and N55 PS pulleys are?

Couldn't tell you, sorry.

kaizzer · 07-20-2018, 03:24 PM

Thanks for sharing, my belt shredded over the weekend while cruising down the highway. I then had to limp it about 3 miles or more....
The car has already had the housing gasket, crank seal, automatic belt tensioner and few other co-related parts replaced less than 4k miles ago: needless to say i'm far from "chill" about it.

Oh well, waiting on the new parts to arrive in the mail and hopefully not too much damage was done besides the belt and ruined compressor.

Thanks again for the info and i'll keep you all posted.

P.S.

pardon me as i didnt mean to hijack your thread!

07-11-2018, 10:36 PM	#1
cahme Second Lieutenant 114 Rep 226 Posts Drives: '11 E90 335i Sport MT Join Date: Jul 2015 Location: Texas iTrader: (0)	Belt started shredding Was driving my 2011 N55 335 home from work and heard a bit of an odd ticking sound, especially around 1800 RPM. When I checked I noticed my belt looked a little skinny and had something flapping during every rotation. See pics attached. My belt was shredding and have a couple thoughts: a) I'm not sure if these partially shredded belts get past the front seal, or if it's just when the belt brakes? I wonder if changing the oil and checking for bits is enough? This really scares me, yet I really don't want to drop the pan. b) What could have caused this? There's no oil from OFHG or anywhere else .. I definitely could be looking at a much worse problem! Belt is a Continental brand and changed out about 40k mi and 2 1/2 years ago. Tensionor and idler pulley were changed then as well. All pulleys spin smoothly and I don't see what could be an issue. It was starting to get dark when I was digging in, so I called it a night. I'm not driving it until I'm confident it's good to go. Here are some pics comparing it to the previous belt @ correct width as well as what's still on my splash shield. I need to go back and see what's up with string that is hanging. The side that is coming apart is the side closest to the engine, if that helps. Attached Images
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07-12-2018, 05:35 AM	#4
Bimmer Pleaser First Lieutenant 205 Rep 349 Posts Drives: nothing Join Date: Jan 2017 Location: Pike Place iTrader: (0)	Belt can absolutely get sucked into the engine, I personally have heard of multiple cases. The main culprit as you probably know is a leaking OFHG which causes the belt to get dislodged and wrapped around the shaft. Hopefully it’s not the case with yours but the only way to be sure is drop the oil pan as far as I know.
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07-12-2018, 05:48 AM	#5
mecheng77 Colonel 1006 Rep 2,243 Posts Drives: 2007 328i / 2014 M235i Join Date: Nov 2017 Location: Ontario Canada iTrader: (0) Garage List [0.00] [0.00]	Wow surprised it went so early. I’ve had belts easily last 250k on other cars. Maybe there is a sharp burr somewhere
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07-12-2018, 01:35 PM	#6
tpknet Registered 2 Rep 1 Posts Drives: 2011 328xi Join Date: Jul 2018 Location: mpls, MN iTrader: (0)	Some things to try I am dealing with this exact problem right now. Some things you can try before you pull the oil pan to see if you have a problem: Unwind and an all pieces of belt from the crankshaft. If you do this carefully and look closely you should find some of it that goes in past the seal if it has. It can also destroy that front seal which should be obvious if it is really bad. On mine there was no rubber left on the front crank seal, all that was left was the steel support ring that is supposed to be an integral part of the seal. Drain the oil through a paint filter. You can find these at any paint store like Sherwin Williams or Benjamin Moore. I found tiny pieces of rubber in the oil. really tiny, so tiny they made it past the screen in the oil pickup tube. However, you should be able to see them. Maybe some kevlar fuzz as well. Cut the oil filter and check it for tiny rubber pieces, I found them in my filter. If all of that looks OK you could take a chance on driving it. The biggest problem from the belt getting shredded in the engine by the timing chain seems to be loss of oil pressure as it plugs the oil intake screen. The chance you are taking by driving it further if there is enough in there to cause problems and you don't detect it by the above methods is that when mine got plugged, somehow those tiny bits of rubber made it past the filter. I found them in the oil galleys in the crankshaft and on the rod bearings when I pulled the rod bearings. I think this last bit is why even after these engines are "repaired" the engines burn up after 6 months. I am not sure what to do with mine now that I found the rubber on the rod bearings. Good luck, I hope yours didn't make it as far as mine did. Please keep your post updated with what you find out.
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07-12-2018, 01:52 PM	#7
IllSic_Design Colonel 2124 Rep 2,758 Posts Drives: 09 E92 335i Join Date: Jun 2016 Location: Northern California iTrader: (1)	Check the power steering pump pulley, they can crack/break apart and rip the belt apart. I just had to change a guy's out after he shredded a belt and his pulley was not even hitting the subframe, it just started to disintegrate.
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07-11-2018, 10:44 PM	#2
e90yyc Art Collector 2425 Rep 3,449 Posts Drives: 2007 328xi (GM-delete 6MT) Join Date: Feb 2018 Location: Canada iTrader: (0)	Based on that I kind of doubt any belt made it past your front main seal. In order for the belt to be ingested, it would probably have to wrap around the crank first, which would then cause it to essentially ‘screw’ its way through the seal. If I was an eng I’m sure there would be a better term for this, but hopefully it makes sense. No idea what might have caused your failure, but I would think you’re in the clear for belt ingestion. Also, thank you for the good pics!
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07-11-2018, 11:00 PM	#3
tlow98 Major General 2185 Rep 5,000 Posts Drives: 2009 E91, 2014 F15 x35i Join Date: Aug 2011 Location: Bay Area iTrader: (2)	Could look for bits in your oil via a change, but I’m guessing you’re fine. Great catch!
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07-12-2018, 03:35 PM	#10
e90yyc Art Collector 2425 Rep 3,449 Posts Drives: 2007 328xi (GM-delete 6MT) Join Date: Feb 2018 Location: Canada iTrader: (0)	I've also heard of bad A/C pulleys as well. Worth checking.
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07-12-2018, 10:13 PM	#12
cahme Second Lieutenant 114 Rep 226 Posts Drives: '11 E90 335i Sport MT Join Date: Jul 2015 Location: Texas iTrader: (0)	Thanks for the suggestions and comments ... Good stuff. I didn't get a chance to look at it at all today. pknet, did you catch it before the belt broke? I live the paint filter idea as I was thinking I'd be able to see any bits just 8n the pan. Will also cut the filter as well to check. The pulley info is also great. I was focused on checking them quickly for bearing wear but didn't think about them being plastic. I had tried to check for subframe contact, but need better light for that. I didn't have any belt wrapped around the crank and he more I think about it, I don't think I shreaded enough belt substance to have forced it through the seal. I still want to take any reasonable precaution, though I'll keep y'all posted as I make progress.
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07-13-2018, 07:14 AM	#14
cahme Second Lieutenant 114 Rep 226 Posts Drives: '11 E90 335i Sport MT Join Date: Jul 2015 Location: Texas iTrader: (0)	Well, the PS Pulley votes pulled through here. Whether or not it was caused by motor mounts are not is yet to be determined, but I'll likely change them out as well. I'll report back what I find from a hitting the subframe standpoint. Here's a pic of the pulley: Attached Images
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07-20-2018, 03:24 PM	#21
kaizzer New Member 2 Rep 8 Posts Drives: 2009 Z4 35i Join Date: Jul 2018 Location: Up North iTrader: (0)	Thanks for sharing, my belt shredded over the weekend while cruising down the highway. I then had to limp it about 3 miles or more.... The car has already had the housing gasket, crank seal, automatic belt tensioner and few other co-related parts replaced less than 4k miles ago: needless to say i'm far from "chill" about it. Oh well, waiting on the new parts to arrive in the mail and hopefully not too much damage was done besides the belt and ruined compressor. Thanks again for the info and i'll keep you all posted. P.S. pardon me as i didnt mean to hijack your thread!
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