[maxspeedusa]

Hello, everyone, this is my first post. I enjoy reading posts and I figured its time for me to post as well and help the community. Well, I was working on a 2007 328i N52 that came in with a destroyed Drive Belt, I noticed a good oil leak from oil filter stand looks like it was leaking for a while, I also replaced the belt tensioner and pulleys. To my surprise, after the repair car wouldn't start, after initial checks I ended up taking compression as the engine was turning but had all the signs of no compression, turns out that it had 0 PSI on most cylinders. Ended up removing the valve cover and noticed many pieces of the drive belt in timing chain area, pieces were all over the place and obviously, it screwed up the timing explaining the no start. So bottom line that oil filter stand leak is the main culprit, by leaking on the drive belt over the years it weakened the belt explaining the damaged caused. Looks like the belt gets sucked in via the crankshaft. So if you have an oil leak on the oil filter stand it's a good idea to replace it and of course depending on mileage, look at the belt tensioner and the pulleys. Unfortunately, this turns out to be a big repair and could have been avoided.

[TheMidnightNarwhal]

Most people will probably complain that this has been posted serveral times... but I say thank you this is great reminder to some.

Replaced my OFHG and cooler gasket soon as I got the car because I saw some traces of oil in my coolant.

[mxchris727]

Sorry to hear about your engine. Hopefully a top-end rebuild with new valves and guides will bring it back to life if a valve was not dropped.

[lowrydr310]

Have any N52s snapped a belt and NOT had it push through the crankshaft seal? Obviously the best option is to do preventative maintenance and replace your belt/tensioner long before it's close to snapping, but I'm wondering if this is the most likely outcome of a broken belt due to the design of the harmonic balancer being on the outside of the pulley, leaving a broken belt with nowhere to go but through the seal.

[dwashy]

Originally Posted by lowrydr310

Have any N52s snapped a belt and NOT had it push through the crankshaft seal? Obviously the best option is to do preventative maintenance and replace your belt/tensioner long before it's close to snapping, but I'm wondering if this is the most likely outcome of a broken belt due to the design of the harmonic balancer being on the outside of the pulley, leaving a broken belt with nowhere to go but through the seal.

I had this happen to me. Wrapped around crankshaft pulley, but didn't go through seal. Seems I was very lucky. Was also due to a leaking oil filter seal

[ctuna]

Oh the horror

broken belt
https://www.e90post.com/forums/showthread.php?t=1305990
http://www.bimmerfest.com/forums/sho....php?t=1231881
http://www.e90post.com/forums/showpo...3&postcount=23
http://www.e90post.com/forums/showthread.php?t=1477111

Mike Miller schedule say's to replace the tensioner every
60k. even if no oil leaks on the belt.

[Fritzer]

Originally Posted by maxspeedusa

Looks like the belt gets sucked in via the crankshaft.

Holy sh*t that sounds intense! Must have been some nice sounds coming from that one when it happened.

[racermp]

Talked about many times. At this point, you are royally f'ed. Start looking for a new motor

[banglenot]

Just a comment on folks describing this as a broken belt. These things almost never break.

This failure most often occurs when the belt slips off the pulleys, mostly due to the deterioration of the tensioner assembly or idler pulley. If oil gets on the belt, it slips off sooner -- but the problem originates in the tensioner.

Then the belt is shredded by the crank, and some pieces get forced past the seal as the belt compresses and shreds.

Crappy design that could be fixed by putting edge lips on the relevant pulleys.

[floydarogers]

This seems to be a bit more common on the diesels - several examples seen.

A new engine is indicated because there is "stuff" in the crankcase oil journals, too, and the pistons likely will know even if the top end is rebuilt.