[NewHotness]

I had been noticing some oil leaks on the ground after parking my car overnight so I took it in to my shop to get it looked at. They noticed it was coming from the oil filter housing and replaced both of the gaskets.

I mentioned that I was also occasionally getting smoke coming from under the hood when pulling up at lights so there must be a leak on the hot side also. After putting it up on the hoist they could see that the valve cover gasket was also weaping slowly but they had no time to fix at that time.

A day or two after the oil filter gaskets were changed and the engine steam cleaned I was driving home from work and just gently cruising on a main road and heard a strange noise, I tried to pull off onto a side road and noticed I had very little steering.

I popped the hood and could see bits of drive belt eveywhere, turned it off and had a tray top tow truck take it back to the shop again. I managed to damage four pulleys with the broken belt and they said they had to unwind broken bits from behind the pulleys to be able to clean it up.

A few days later and I start to notice the oil on the ground again so I book in the valve cover gasket to be done today. They pulled off the valve cover and noticed there were broken bits of the old belt that had forced its way into the engine and the timing chain via the front seal of the crank shaft!!!!

They managed to fish most of it out but said there were a few very small peices at the bottom of the timing chain that would need some thought as to what to do. A few hours later and after putting it back together and putting it up on the hoist they noticed the oil is slowly draining from what appears to be a damaged front main seal.

I am not sure what goes into changing this but I know it it cant be quick and easy

All from a broken belt! I would highly recommend having the belt changed at a service interval prior to 100,000kms to avoid this mess!

[Tzu]

Is there any evidence of accessory belt contact with your subframe?

[NewHotness]

Nothing that I or the guys from the shop could see.

[NewHotness]

Looks like I am not the only one unfortunately:

http://www.n54tech.com/forums/showthread.php?t=19155

[Indo Rider]

So do we think this occurs because of an old/worn/failed belt, belt contact with subframe near PS pulley, or other? Thinking about this in response to OPs comment to replace belt before this happens... I have to think there are plenty occurances of belt failure without it getting sucked into the engine through crank seal right? Agree its good preventative maintenance item, but would like to understand why exactly this happens...

[Kommodore]

Make sure you check your power steering pulley, it might be shattered or chipped and shred the next belt too. Happened to me. Fortunately my front main seal isn't leaking, so I don't think any bits have gotten past it.

[NewHotness]

The research I did when it initially snapped was that it can be caused by:

1/ Subframe contact on earlier models
2/ Oil leaks that make it possible for the belt to slip
3/ Damaged power steering pulley
4/ The dealer told me they do it every 100,000kms as routine maintenance as its rubber and will fail.

I could not find any evidence of subframe contact and the pulleys showed no obvious signs of wear when the oil filter gaskets were changed. I definitely had oil over the belt from the leak which was then steam cleaned off. For me it may have been a combination of age, oil leak and then the steam clean

I had to replace all the pulleys due to the damage caused by the belt.

[SneakyDeeky]

A few months ago I had a coolant leak that got onto my alternator / hydraulic steering pump. It made the belt squeal like a 2nd grader high on Halloween candy and I just figured I'd replace it when I got around it to it... Bad decision. After a few weeks, it slipped off the pulleys and got shredded like the pictures above, but it happened while I was on a "spirited drive" through the canyons, which surprised the heck out of me as I suddenly had no power steering mid turn. Then I had to drive home 50 miles with no alternator, which killed my battery.

Take-away: belt changes are important.

Sorry for the bad luck, OP.

[Vroom]

Originally Posted by NewHotness

They pulled off the valve cover and noticed there were broken bits of the old belt that had forced its way into the engine and the timing chain via the front seal of the crank shaft!!!!

They managed to fish most of it out but said there were a few very small peices at the bottom of the timing chain that would need some thought as to what to do. A few hours later and after putting it back together and putting it up on the hoist they noticed the oil is slowly draining from what appears to be a damaged front main seal.

.



Can someone explain how parts of a shreaded belt can get inside the engine past the front crankshaft seal? Is there another path besides the 0.001" clearance between the crankshaft and bearing?

[NewHotness]

Well I think this may go a little way to explain it. The seal is supposed to come out very easily with the correct BMW tool but it was badly damaged by the belt and it nearly came to pulling out the engine and the crank but after a day and a half it finally met its maker ....



Now the issue is that the attempts to get it out has scored the metal on the inside where the seal meets the crank pulley so a new seal wont seal properly. My shop is recommending a speedi sleeve as opposed to dropping the timing in order to remove the part that is scored. Anyone have an opinion on this??

All due to broken drive belt! I think I will be changing it every 20,000kms instead of the recommended 100,000kms from now on ... would be a cheaper excercise!

[Vroom]

Nasty pic. Even with the seal totally gone, I still don't know how a chunk of belt & cord (shown in your first pic) can squeeze between the .001" gap between crank journal & bearing...

[big_c]

Ouch. Glad that im replacing my belt and upper idler pulley now with a contitech belt...just wish I knew how to pull the damn front turbo inlet pipe off the turbo to gain clearance! I can wiggle it around but am afraid something might break.

[Vroom]

Remove the radiator fan, un-clip the coolant hose from the plastic bracket and remove bracket and you can loosen tensioner to R&R belt.

[big_c]

Originally Posted by Vroom

Remove the radiator fan, un-clip the coolant hose from the plastic bracket and remove bracket and you can loosen tensioner to R&R belt.

Does that turbo inlet pipe just press on to the turbo? No clamps or anything to undo? If I pull the pipe to the front of the car I can see the rubber coupler on the turbo start to slide back off the turbo

[Vroom]

Bentley manual says to remove duct mounting bracket bolts and fold the duct down without disconnecting or removing.

[big_c]

Gotcha. So basically disconnect the coolant clip, mounting bracket bolts, airbox connections...then just push the duct downwards, sort of rotating it clockwise

[Vroom]

Yeah, I quoted Bentley cause it's been a year & I don't remember exactly. I needlessly replaced the tensioner & idler pulley as well and do recall it was NOT a PITA.

[big_c]

Yeah, I was considering just doing all of the pulleys, but I figured I would just check when I had the belt off. The tensioner pulleys are fine with the proper resistance, lower idler seems like new, and the upper idler pulley was totally shot, with the dry bearing noise/ grease leaking from front and spun forever when rotated it..

Have a new one on order now, installing tomorrow AM.

[raceyBMW]

Jesus christ this is just insane....I know others have had the same issue, but I also just cannot see how the belt gets ingested through the front main seal, there is so little gap there!

[Jason @ BMS]

Originally Posted by raceyBMW

Jesus christ this is just insane....I know others have had the same issue, but I also just cannot see how the belt gets ingested through the front main seal, there is so little gap there!

Insane. Excuse me while I go inspect my belts.

[NewHotness]

You're telling me!

I think I will be inspecting them every morning for the next few weeks just to be sure, that is once I get it back!

The speedi sleeves seem to be a common application in a lot of engines regarding the front and rear seals but I had never heard of them until now.

I can get the replacement hub fairly cheap but once you undo the bolt the sprocket will let go and the engine timing will be need to set up again from scratch ... from what I have read, this is not a nice or quick/easy process.

[big_c]

Originally Posted by Jason @ BMS

Insane. Excuse me while I go inspect my belts.

My original 07 belt with nearly 100k looks fantastic...no cracks or frays or anything...the rubber is just kinda hard and somewhat glazed looking compared to the new softer material.

I was very relieved to see no damage to the PS pulley and no black marks on the subframe, along with even wear marks on the belt.

[NewHotness]

My advice, and I may not be in the best mindset to give it, is to change it!! Especially if its going hard.

Very inexpensive compared to the alternative, especially after 100,000 miles

My stealer said 100,000 kms was the scheduled change.

[big_c]

I second the recommendation to change it. Its a piece of cake especially if you have manual..auto only complicates it by requiring you to raise the car and remove splash shield.

The belt is 20 bucks. Easy DIY

[dsjr2006]

Exactly the same issue here!