N54 FAILURE - searching for answers

[nvrtoofast]

I've been scouring the internet for an answer. While driving my e61 535 it failed on me.

While on cruise control at 80 mph on the highway the engine hesitated. I shredded a belt the week before and was concerned so I slowed and pulled over. The car immediately shut down and went to park. Would not restart. It also was smoking from under the hood and smelled like burnt rubber.

at my shop I pulled the plugs and found nothing wrong. I looked underneath and found nothing wrong. will have to pull the pan next and dig deeper.

Before that. I'm hoping someone might point me in a direction on this.

turned crank with wrench. Not seized. Timing chain??

Any thoughts?

[R Shaffner]

Do you know what caused the belt to shred? If something the belt turned failed or was starting to fail, it could have happened again.

[pbonsalb]

One issue with belt failure on the N54 is the possibility of part of the belt going through the seal behind the crank pulley. Most of these cars need a major servicing to get rid of the oil leaks that lead to the belt failure — oil filter housing to cooler gasket, oil filter housing to block, oil filter housing oil cooler o-rings, oil cooler U shaped hose (the hose on the other side seems to last), oil pan gasket.

Can’t help on why it won’t start when the crank is not frozen but a shredding belt can take out wiring as it whips around. I’d probably also pull codes and then clear them in case a stored code is the issue.

[nvrtoofast]

UPDATE:

I have fixed the wagon and it was an interesting string of issues.

- I pulled the spark plugs to check the cylinders. Everything was good.
- I drained the oil to look for metal shavings. Nothing there.
- I removed the intake to follow the burnt smell. This led me to the starter. After i removed it it was rattling. The interior was burnt and clearly disintegration.
- I then turned the motor by hand. It was very stiff. I then removed the belt. The Alternator was seized. I think this is mainly due to the belt stripping (not verified).
- So I changed the alternator AND the Starter.

I put everything back together and all good. I still have no Idea why the two things would break at the same time.

In regards to the belt stripping. This was directly due to a cracked oil cooler. It cracked when the fan exploded at a stop light. All is now fixed. It has been an interesting summer.

All of this doesn't even mention the exploding tire in July. lol

[pbonsalb]

Yes, it is really odd that the starter motor and alternator both failed at the same time. That you changed the oil and found no pieces of belt is a good sign. Did you cut open the filter for a look? The biggest concern is pieces of belt getting last the crank seal. There are reports of it happening without any obvious signs when just looking at the seal from the outside.

[fred530xi]

nvrtoofast,
Worst case scenario is pieces of the belt are sucked into the engine oil crankcase and then clog the oil pickup. Obviously, no oil means destroyed engine.
If the belt originally shredded due to the alternator, maybe the starter was cranked one too many times and decided to fail. Who knows; but sounds like you are relatively fortunate.
Would recommend you measure oil pressure to ensure oil pickup is not clogged. Easier than dropping the oil pan and looking for belt material.
Good luck
Fred