DIY: Shredded / Broken Serpentine Belt Repair/Inspect Procedure

mr_malvo · 09-18-2016, 04:03 PM

I experienced a shredded serpentine belt a while ago and my experience with it prompted me to write a thread with consolidated information. No doubt there is a lot of information out there regarding belts, broken seals, seized engines etc. However, I felt like it was all scattered and someone like me could have benefited from a once stop thread for all the things that one must check after experiencing a shredded serpentine belt.

My goal with this is to hopefully help someone that goes thru a similar failure scenario and catch the problems before your engine seizes.

Background:
There are several failure scenarios out there that cause a serpentine belt to shred:
- Oil Leaks from Oil Filter Housing Gasket
- Engine mounts allowing power steering pulley to contact sub-frame.
- Faulty belt pulleys/tensioner.

Here is what my belt looked like after it thought I had removed all the pieces from the engine bay.

No matter the cause, once the belt shreds if not handled properly it will be the beginning of bigger problems.

The worst case scenario goes like this:

1. Serpentine belt shreds
2. Pieces of belt wrap around the crankshaft behind the pulley sight unseen

2.a. Owner replaces belt and continues to drive car unaware of belt behind pulley

3. The pieces of belt break past the front crankshaft seal and get tangled in the timing chain.

3.a. This could have happened during the initial belt failure.

4. The timing chain further shews up the belt and pieces fall into the oil pan.

4.a. Big enough pieces of belt can cause your timing chain to skip a tooth.

5. The pieces of belt that fell in the oil pan get sucked in by your oil pick-up.
6. Oil pick-up gets clogged up.
7. Your engine seizes up due to oil starvation.

7.a. If 4.a happens your engine valves can hit pistons due to offset timing.

So how can all this be prevented?

Well, after a shredded belt occurs:

1. REMOVE your front pulley and check for pieces of belt wrapped behind there and also the condition of your front seal.

1.a. If there is none, then you my friend are lucky. Proceed with changing your belt. Here is a Good DIY for That

1.b. If after removing your pulley the seal looks compromised, then you're going to have to do some cleanup. The picture below shows what my seal looked like and the smoking gun piece of belt telling me I had lots to do.

2. A damaged front crankshaft seal probably means pieces of belt made their way into the engine. The amount that did varies from case to case however, please note there's no way of telling how much was ingested until you go in there.

3. Use THIS DIY to REMOVE VALVE COVER.

3.a. With your valve cover removed check for pieces of belt all around the timing chain. The picture below is from my car. I didn't have that much belt clearly visible, however there were pieces wrapped down the pointed areas.

4. Use THIS DIY to REMOVE OIL PAN

4.a. With the oil pan removed check the surrounding areas for belt pieces, but must importantly, your oil pick-up tube. The picture below is what my oil pan and pick-up tube looked like. You can see that is does not take much to start clogging your pick-up tube.

Added substeps (4.b & 4.c) to incorporate Feedback From ThaGill .

4.b When looking at your oil pick-up tube inspect for debris that might not come out from the one side either because they are too small or stuck. In that case remove the oil pick-up tube from the engine block (3 screws) and detach from the oil pump.

4.c. Spray the oil pick-up tube from the other side with parts cleaner. The pictures below are from ThaGill and the debris he got out by blowing on the tube from the other side.

5. With the oil pan removed you will have clear access to the oil pump and the front part of the crankshaft. Look for belt pieces in those areas as well.

5.a. While you're down there inspect the subframe and power steering pulley for damage. My PS pulley was in good condition, and so were the engine mounts.

6. Use THIS DIY to Remove/Replace your front crankshaft seal.

So there you have it. The best advice I can give is to NOT DRIVE YOUR CAR after experiencing a shredded serpentine belt. Check behind that front pulley to avoid yourself future headaches.

I hope this is of help to someone out there. And I'm open to comments/suggestions to expand the information here.

BashShah · 09-19-2016, 02:46 AM

Awesome FYI, this should be a sticky.
And thanks for suggesting my Belt and tensioner DIY.

This Thread is extremely well written to address this issue.

Good job Mr. Malvo

mr_malvo · 09-19-2016, 01:01 PM

Sure thing, man. Your DIY was also very helpful so quoting it was a no brainier.

Quote:

Originally Posted by DarkNemesis

Awesome FYI, this should be a sticky.
And thanks for suggesting my Belt and tensioner DIY.

This Thread is extremely well written to address this issue.

Good job Mr. Malvo

ThaGill · 11-17-2016, 11:08 AM

This is an awesome write up, you definitely saved my ass. Happened to me right after i had a leak from my oil filter housing. I changed the gaskets but i guess there was still oil all over my belt and pulleys. Took me some time but i was able to get all the parts and fix my car (Im in Canada so specialty tools are hard to get your hands on). Thanks for the awesome write up!

mr_malvo · 11-17-2016, 12:04 PM

Really glad to know it helped. I'm Feeling accomplished!.

Quote:

Originally Posted by ThaGill

This is an awesome write up, you definitely saved my ass. Happened to me right after i had a leak from my oil filter housing. I changed the gaskets but i guess there was still oil all over my belt and pulleys. Took me some time but i was able to get all the parts and fix my car (Im in Canada so specialty tools are hard to get your hands on). Thanks for the awesome write up!

mr_malvo · 11-27-2016, 12:49 PM

Your input has been incorporated. Thanks for the feedback.

Quote:

Originally Posted by ThaGill

This is an awesome write up, you definitely saved my ass. Happened to me right after i had a leak from my oil filter housing. I changed the gaskets but i guess there was still oil all over my belt and pulleys. Took me some time but i was able to get all the parts and fix my car (Im in Canada so specialty tools are hard to get your hands on). Thanks for the awesome write up!

DuvanLouis · 11-22-2017, 02:56 PM

Excellent write up. Amazing how much detailed and helpful in many levels of information you can find on here

mr_malvo · 11-23-2017, 12:23 PM

Quote:

Originally Posted by DuvanLouis

Excellent write up. Amazing how much detailed and helpful in many levels of information you can find on here

Thanks, man. I too can say the same about this forum. Tons of good info.

STurnerXM2010 · 11-27-2017, 02:56 AM

I called BS when my SA came back and said the front main seal had sucked pieces of the belt into the crankcase. LOL Made him take me back there and show me where it had gone through the main seal. Sure as s*** it went through the front main. Apparently, it's common as hell.

El Cheapo Loco · 11-27-2017, 05:15 PM

I was fortunate enough to learn of this phenomenon early in my e9x ownership when I saw an e90 getting its engine swapped at my indy. I chatted up the mechanic and he told me how the belt ingestion started with an OFHG leak. Since then I have been diligently checking for oil leaks and have warned others the importance of doing so.

AndyW · 08-03-2018, 10:20 PM

Thx for this thread! My son's 2008 335i had the dreaded power-steering-pulley-hit-the-subframe casualty. The belt shredded. I pulled the main pulley and while there were a few strands of belt curled up back there, it looked like the below pics, which I think looks OK. It does have a couple of "divots" in it, but no belt strands and no oil leaking. Also, it looks like almost all of the belt material is accounted for when you lay it all out. Anyone think otherwise before I put it back on?

mr_malvo · 08-03-2018, 10:45 PM

That seal looks uncompromised to me.

AndyW · 08-04-2018, 10:30 AM

Quote:

Originally Posted by mr_malvo

That seal looks uncompromised to me.

Thx. He got lucky! Was there ever a solution outside of warranty for this issue from BMWNA? Granted, I am pretty sure the precipitating event was him running over a parking bumper thw day before this happened so there is some culpability on my son's part!

Thx again for your original post. Really helpful

TheMidnightNarwhal · 08-14-2018, 08:03 PM

How exactly do you avoid this? If the belt look nice dark and no cracks everything should be good?

Like my OFHG was leaking and I replaced it, cleaned the belt after with simple green and power washer. How can I make sure all good?

mr_malvo · 08-15-2018, 12:08 PM

Preventive maintenance is the way. Do periodic checks and replace the belt at it's scheduled internal. In your case you already fixed the OFHG which is a step in the right direction.

We also have visual access to portions of the belt, so check those for any obvious signs of damage. And look at the pulleys to make sure they don't have damaged edges.

Some folks might go a little farther than that and replace engine mounts. I didn't do so on my car.

Quote:

Originally Posted by TheMidnightNarwhal

How exactly do you avoid this? If the belt look nice dark and no cracks everything should be good?

Like my OFHG was leaking and I replaced it, cleaned the belt after with simple green and power washer. How can I make sure all good?

Psyphertext · 08-15-2018, 10:29 PM

Please make sure this is in Stickies.

TonyMorrone · 10-23-2018, 12:34 AM

Thank you for posting this. It looks pretty much the same as what has just happened to my BMW 335i. Although I had an oil filter seal replaced 3 months ago. They hadn't replaced the seal on the coolant gasket which caused a lot of oil to leak onto my serpentine belt. Then the belt broke & wrapped around the crankshaft seal & got sucked in.

nick_is · 11-06-2018, 01:09 PM

Glad to have found this thread! Belt shredded this past Sunday. Have not verified if crank seal is compromised.

msp2three35i · 11-07-2018, 08:37 AM

Thanks for the diy. Didn’t find any pieces when I opened the valve cover but found some blocking the oil feed tube when I opened up the oil pan. Very grateful for this thread.

nick_is · 11-09-2018, 11:36 AM

Does anyone have any opinions on the condition of my seal? There is oily/greasy residue across the front of the motor. I did not find any belt pieces behind the pully, but there was belt wire wrapped around the pulley itself.

mr_malvo · 11-09-2018, 12:24 PM

Your seal looks intact! All that oil and grime is coming from somewhere else.

Quote:

Originally Posted by nick_is

Does anyone have any opinions on the condition of my seal? There is oily/greasy residue across the front of the motor. I did not find any belt pieces behind the pully, but there was belt wire wrapped around the pulley itself.

klargo · 03-12-2019, 07:28 AM

My used 2013 X5 has 58k so I wasnt concerned about drive belts quite yet. I was returning home from a long trip when I threw belt. Not knowing off this issue I took my chance and drove it home. When I went to replace belt I found it shredded and pieces stuck behind harmonic b that I couldnt easily get out. After remving HB I had pieces of belt wrapped around crank and sticking out of oil seal. The seal is completly gone and even have a few small gouges in metal. I'm older and not looking FWD to the DIY work involved so I called dealer service dept who are familair with this issue. They quoted a price of (approx) $3500 to complete inspection and work needed. I told them I was considering doing myself and was told I would not be able to complete all neccesary steps such as flushing system and risking further issues. I just wanted opinions as to what others think about this. I will do the work myself to save 2-3k but wanted to make sure procedure on this site is thorough enough. The suspected cause of belt failing is oil cooler housing leaking oil on belt. Also thanks so much to those sharing info I just wish I would have found it earlier!

09-18-2016, 04:03 PM	#1
mr_malvo Private 53 Rep 70 Posts Drives: 2008 335i Join Date: Feb 2016 Location: South Florida iTrader: (1)	DIY: Shredded / Broken Serpentine Belt Repair/Inspect Procedure - E90, E9X 335i N54 I experienced a shredded serpentine belt a while ago and my experience with it prompted me to write a thread with consolidated information. No doubt there is a lot of information out there regarding belts, broken seals, seized engines etc. However, I felt like it was all scattered and someone like me could have benefited from a once stop thread for all the things that one must check after experiencing a shredded serpentine belt. My goal with this is to hopefully help someone that goes thru a similar failure scenario and catch the problems before your engine seizes. Background: There are several failure scenarios out there that cause a serpentine belt to shred: - Oil Leaks from Oil Filter Housing Gasket - Engine mounts allowing power steering pulley to contact sub-frame. - Faulty belt pulleys/tensioner. Here is what my belt looked like after it thought I had removed all the pieces from the engine bay. No matter the cause, once the belt shreds if not handled properly it will be the beginning of bigger problems. The worst case scenario goes like this: 1. Serpentine belt shreds 2. Pieces of belt wrap around the crankshaft behind the pulley sight unseen 2.a. Owner replaces belt and continues to drive car unaware of belt behind pulley 3. The pieces of belt break past the front crankshaft seal and get tangled in the timing chain. 3.a. This could have happened during the initial belt failure. 4. The timing chain further shews up the belt and pieces fall into the oil pan. 4.a. Big enough pieces of belt can cause your timing chain to skip a tooth. 5. The pieces of belt that fell in the oil pan get sucked in by your oil pick-up. 6. Oil pick-up gets clogged up. 7. Your engine seizes up due to oil starvation. 7.a. If 4.a happens your engine valves can hit pistons due to offset timing. So how can all this be prevented? Well, after a shredded belt occurs: 1. REMOVE your front pulley and check for pieces of belt wrapped behind there and also the condition of your front seal. 1.a. If there is none, then you my friend are lucky. Proceed with changing your belt. Here is a Good DIY for That 1.b. If after removing your pulley the seal looks compromised, then you're going to have to do some cleanup. The picture below shows what my seal looked like and the smoking gun piece of belt telling me I had lots to do. 2. A damaged front crankshaft seal probably means pieces of belt made their way into the engine. The amount that did varies from case to case however, please note there's no way of telling how much was ingested until you go in there. 3. Use THIS DIY to REMOVE VALVE COVER. 3.a. With your valve cover removed check for pieces of belt all around the timing chain. The picture below is from my car. I didn't have that much belt clearly visible, however there were pieces wrapped down the pointed areas. 4. Use THIS DIY to REMOVE OIL PAN 4.a. With the oil pan removed check the surrounding areas for belt pieces, but must importantly, your oil pick-up tube. The picture below is what my oil pan and pick-up tube looked like. You can see that is does not take much to start clogging your pick-up tube. Added substeps (4.b & 4.c) to incorporate Feedback From ThaGill . 4.b When looking at your oil pick-up tube inspect for debris that might not come out from the one side either because they are too small or stuck. In that case remove the oil pick-up tube from the engine block (3 screws) and detach from the oil pump. 4.c. Spray the oil pick-up tube from the other side with parts cleaner. The pictures below are from ThaGill and the debris he got out by blowing on the tube from the other side. 5. With the oil pan removed you will have clear access to the oil pump and the front part of the crankshaft. Look for belt pieces in those areas as well. 5.a. While you're down there inspect the subframe and power steering pulley for damage. My PS pulley was in good condition, and so were the engine mounts. 6. Use THIS DIY to Remove/Replace your front crankshaft seal. So there you have it. The best advice I can give is to NOT DRIVE YOUR CAR after experiencing a shredded serpentine belt. Check behind that front pulley to avoid yourself future headaches. I hope this is of help to someone out there. And I'm open to comments/suggestions to expand the information here. Last edited by mr_malvo; 08-27-2017 at 12:15 PM.. Reason: Added Feedback from user.
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09-19-2016, 02:46 AM	#2
BashShah Colonel 311 Rep 2,015 Posts Drives: 2012 335i Sedan Join Date: Oct 2012 Location: Vancouver, Canada iTrader: (0)	Awesome FYI, this should be a sticky. And thanks for suggesting my Belt and tensioner DIY. This Thread is extremely well written to address this issue. Good job Mr. Malvo
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11-17-2016, 11:08 AM	#4
ThaGill Registered 0 Rep 1 Posts Drives: 2007 335i Join Date: Jun 2015 Location: Toronto iTrader: (0)	This is an awesome write up, you definitely saved my ass. Happened to me right after i had a leak from my oil filter housing. I changed the gaskets but i guess there was still oil all over my belt and pulleys. Took me some time but i was able to get all the parts and fix my car (Im in Canada so specialty tools are hard to get your hands on). Thanks for the awesome write up!
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11-22-2017, 02:56 PM	#7
DuvanLouis Registered 0 Rep 3 Posts Drives: E93 N54 Join Date: Oct 2017 Location: Elizabeth NJ iTrader: (0)	Excellent write up. Amazing how much detailed and helpful in many levels of information you can find on here
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11-27-2017, 02:56 AM	#9
STurnerXM2010 New Member 4 Rep 14 Posts Drives: 2012 335i E92 M-Sport Join Date: Apr 2015 Location: Frisco, TX iTrader: (0)	I called BS when my SA came back and said the front main seal had sucked pieces of the belt into the crankcase. LOL Made him take me back there and show me where it had gone through the main seal. Sure as s* it went through the front main. Apparently, it's common as hell. __________________ 2012 E92 335i M-Sport w/M-Tech**; 6MT, CDV upgrade, BMS Intake, BMS CP, N20 MAP (CP only), VRSF DP, Fuel-It Stage 1 LPFP, BMS oil cooler valve, fully adjustable M3 camber kit, MHD Flash, CF high kick spoiler, M4 black chrome grills, and much more to come...
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11-27-2017, 05:15 PM	#10
El Cheapo Loco douchebaggo 185 Rep 971 Posts Drives: stick Join Date: Oct 2009 Location: CA iTrader: (1)	I was fortunate enough to learn of this phenomenon early in my e9x ownership when I saw an e90 getting its engine swapped at my indy. I chatted up the mechanic and he told me how the belt ingestion started with an OFHG leak. Since then I have been diligently checking for oil leaks and have warned others the importance of doing so.
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08-03-2018, 10:20 PM	#11
AndyW Supreme Galactic Commander (one galaxy over...) 700 Rep 1,784 Posts Drives: '08 E93, '12 E82, '13 E93 M3 Join Date: Feb 2012 Location: Washington, USA iTrader: (5)	Thx for this thread! My son's 2008 335i had the dreaded power-steering-pulley-hit-the-subframe casualty. The belt shredded. I pulled the main pulley and while there were a few strands of belt curled up back there, it looked like the below pics, which I think looks OK. It does have a couple of "divots" in it, but no belt strands and no oil leaking. Also, it looks like almost all of the belt material is accounted for when you lay it all out. Anyone think otherwise before I put it back on? __________________ Best, Andy '12 E82-PS2,Stoptechs,Clubsports+M3 bits,Accusump,Wagner DP+EVO III FMIC,ERCP,BMS Intake,Mason Strut Bar,Wedge Tune
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08-03-2018, 10:45 PM	#12
mr_malvo Private 53 Rep 70 Posts Drives: 2008 335i Join Date: Feb 2016 Location: South Florida iTrader: (1)	That seal looks uncompromised to me.
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08-14-2018, 08:03 PM	#14
TheMidnightNarwhal Major General 2795 Rep 6,382 Posts Drives: 11' 335is DCT Join Date: Jun 2015 Location: Gatineau, Quebec iTrader: (0)	How exactly do you avoid this? If the belt look nice dark and no cracks everything should be good? Like my OFHG was leaking and I replaced it, cleaned the belt after with simple green and power washer. How can I make sure all good?
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08-15-2018, 10:29 PM	#16
Psyphertext Private 6 Rep 76 Posts Drives: 09 328i Join Date: Aug 2018 Location: Mo iTrader: (0)	Please make sure this is in Stickies. __________________ if you didn't have fun, it wasn't difficult enough.
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10-23-2018, 12:34 AM	#17
TonyMorrone Registered 2 Rep 1 Posts Drives: BMW 335i 2008 Join Date: Oct 2018 Location: Toronto iTrader: (0)	Thank you for posting this. It looks pretty much the same as what has just happened to my BMW 335i. Although I had an oil filter seal replaced 3 months ago. They hadn't replaced the seal on the coolant gasket which caused a lot of oil to leak onto my serpentine belt. Then the belt broke & wrapped around the crankshaft seal & got sucked in.
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11-06-2018, 01:09 PM	#18
nick_is Registered 0 Rep 2 Posts Drives: 2011 335is MT Join Date: Nov 2018 Location: Bay Area iTrader: (0)	Glad to have found this thread! Belt shredded this past Sunday. Have not verified if crank seal is compromised.
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11-07-2018, 08:37 AM	#19
msp2three35i Private First Class 13 Rep 103 Posts Drives: TiAg/CR e92 335i Join Date: Jun 2011 Location: Harrisburg, PA iTrader: (2)	Thanks for the diy. Didn’t find any pieces when I opened the valve cover but found some blocking the oil feed tube when I opened up the oil pan. Very grateful for this thread.
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11-09-2018, 11:36 AM	#20
nick_is Registered 0 Rep 2 Posts Drives: 2011 335is MT Join Date: Nov 2018 Location: Bay Area iTrader: (0)	Is my seal compromised? Does anyone have any opinions on the condition of my seal? There is oily/greasy residue across the front of the motor. I did not find any belt pieces behind the pully, but there was belt wire wrapped around the pulley itself. Attached Images
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03-12-2019, 07:28 AM	#22
klargo New Member 3 Rep 16 Posts Drives: 2013 X5 35i Join Date: Mar 2019 Location: NC iTrader: (0)	newbie My used 2013 X5 has 58k so I wasnt concerned about drive belts quite yet. I was returning home from a long trip when I threw belt. Not knowing off this issue I took my chance and drove it home. When I went to replace belt I found it shredded and pieces stuck behind harmonic b that I couldnt easily get out. After remving HB I had pieces of belt wrapped around crank and sticking out of oil seal. The seal is completly gone and even have a few small gouges in metal. I'm older and not looking FWD to the DIY work involved so I called dealer service dept who are familair with this issue. They quoted a price of (approx) $3500 to complete inspection and work needed. I told them I was considering doing myself and was told I would not be able to complete all neccesary steps such as flushing system and risking further issues. I just wanted opinions as to what others think about this. I will do the work myself to save 2-3k but wanted to make sure procedure on this site is thorough enough. The suspected cause of belt failing is oil cooler housing leaking oil on belt. Also thanks so much to those sharing info I just wish I would have found it earlier!
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