danosoo

Pulled the oil pan to clean it and change the gasket. Found this up against the screen in the oil pickup tube. I haven't had the car very long but it didn't appear that the pan had been off before. Have no idea where it could have come from. It looks like spiral shreds from a reinforced rubber hose. The curls look like it was about a 1" dia. Any thoughts of where it might have come from ?

hose

seanjordan20

The previous owner let the belt break and it got sucked up

danosoo

Hi Sean, The serpentine drive belt for the generator, power steering, etc? How could it have gotten inside the engine ?

seanjordan20

It's common in these vehicles if you don't change it before it gives out. It gets sucked through the crank.

twh

Here is what happens...

On the N52 and N54 engines, the crankshaft pulley is real close to the engine. If the serpentine belt comes off, it can get wedged between the space between the crankshaft pulley and the engine. The belts starts to shred...the engine is still turning...the belt pieces get pulled into the engine via the front main seal. Then you have a lot of belt pieces in the engine and typically in the oil pump pickup and all along the timing chain mechanics. If you pulled the pan because if an oil leak, it could be the front main seal. So, if you just bought the car, the previous owner knew this had happened and sold it to you -- nice guys. There are threads and photos on this board and bimmerfest.com with people having the same issue. It can be cleaned out, although you never really know if you got it all. You'll have to get the pan off as you did, but also the valve cover and get to the timing chain parts as it will be there as well.

Back to the serpentine belt. Probably the belt came off due to lack of maintenance. The most likely problem there is sludge build up at the front of the engine, oil leaking from the oil cooler or oil filter housing or a severely worn belt tensioner. I change the belt every couple years. I have used Gunk of the front of the engine twice - cover anything with gears, remove the belt, do the job, hose it off for some time, replace the belt with a new one. I've changed the tensioner twice. I've done the gaskets on the oil filter housing and oil cooler. One more thing that is prone to crap is the hose from the thermostat that lands just near the oil cooler. That hose is generally called the mickey mouse hose because if the ears looking clamp. The plastic clamp hose will break. It could have been a cooling leak that got on the belt and caused it to slip off. You can get a hose with an aluminum fitting or an aluminum fitting to use in the existing hose.

danosoo

Hey TWH , had just looked up in front at the timing gear and crank pully and sure enough, there were a couple strands caught on the timing sprocket. I'm surprised I haven't had a lot of oil leaking out the front. I used the liqui moly engine flush that Sean recommended before I drained the oil and it was about the consistency of diesel fuel. The pan was clean up to the oil level but caked with carbon from there up Didn't notice any major leeks when I got under to drain it. I'll have to look for leaks after i get it back together and clean it good underneath. I changed the valve cover gasket when I first got it. I was surprised to see how clean it was on top. I was amazed to see how much carbon buildup was on the two VANOS screen filters. Going to pull 'em again. The engine seems to produce a lot of it

I see it's not too bad to replace the seal . Can get a kit and a seal for under $100
I bet that oil pump was sure pucker'n trying to suck oil through all that fuzz and rubber. ha ha ha Come to think about it , .he idle sid smoth out with the oil thin as it was.

Thanks for the detailed explanation. Dan

danosoo

I got the oil pan gasket changed and the undercarriage bolted back on. Pretty big job with a lift but doing it alone on jack stands in the driveway ......whoa! Initially, I raised it to pull the pan and change the ATF. Decided to hold off a bit and let the skin on my shoulder blades heal.

Had gotten a front seal and puller/installer thinking it would need to be replaced but evidently it had been done after the belt had been sucked through it. Was really surprised to see it's not leaking oil. Anxious to see how much it burns and how much oil was just leaking.

Still having engine issues. Intermittent rough running. Idle variation pulsing between 500 and about 700 rpm. OBD says misfire 3 and 4 and O2 sensor problem. Runs fine for a while. Service light stays off. Then on the highway seems like more often under a load, like going up a grade, it starts stumble'n and loses power. Don't have a dedicated BMW scanner but will list the actual codes I got tomorrow.

I'm not sure if I should start another thread. Thought I would run it by you two (Sean and TWH) first.

twh

Hard to say. My fear/guess would be there still crap in the engine. Something easy to try is to change the oil and filter every few days until you don't see any sign of more crap. I'd also use a razor knife to cut the oil filter apart and unfold it looking for stuff. You might get lucky and a few oil changes might just settle it down.

danosoo

Thanks T, Would explain it happening intermittently. Reminds me that I need take out the two screens and clean them also. The photo shows how bad they were before. I am finding out how finicky these are about their oil.

seanjordan20

I would definitely die what's stated above. Had you taken the valve cover off to have a look? I would love to see the codes being thrown as it being on just 2 cylinders it might be something in the combustion realm. Did you actually pull the oil pan and if so what procedure did you use (lifting the engine or dropping the subframe). I'm lost at what was actually done