Fault rods Bearings N55 M235i Stage2

[frank35]

Hi guys, I had a problem with the Bearings in my N55 with 45k.

Can they be changed without removing the complete engine from the car? Or just removing the front subframe and removing the crankcase from the engine?

[Weehe]

You can remove the subframe and oil pan to change the bearings. But how do you know there is something wrong with the bearings if you haven't opened it and seen them?

[F87Source]

May oil analysis or he hears excessive noise idk. But doing bearings from under a car with the oil pan off like weehe said is a really annoying job, it is not fun at all.

[F87Source]

Oh and another thing to note is if your bearings are damaged you should also check your crankshaft while you're under there for any scoring. The next thing you should do is flush out your oil supply for any metal debris from the bearings, this will be a really painful job since it could be stuck in the turbos and that'll cause them to blow, and the debris could be in the oil cooler, oil to water heat exchanger, and if you don't do a good job cleaning it your bearings could go again. Or worse you could take out the motor.

[rev210]

Oh ...diagnosing rod bearing issues, tricky... as mentioned you can drop the sump to change but, far from ideal.
What made you think they are cactus?

[Weehe]

Just a note, most people prefer to swap an engine than pull the pan.

[bnks334]

I would rather pull the engine and work on a stand than drop the subframe. It's honestly easier, cleaner, less stressful. But, it's doable on your back. If you have rod knock you have a scored/damaged crankshaft and rods. Slapping in new bearings is hardly ever a complete solution. It can work, but, you better be prepared to swap in a new/used engine. Luckily bearings and an oil pan gasket are cheap. It's like a $300 job. Not much wasted except your labor if it doesn't work.

[F87Source]

Just a note, most people prefer to swap an engine than pull the pan.

The issue is OP has an m235i which has the forged crank, he would have to find an m235i motor which is a bit more difficult than finding a standard n55 which doesn't have the forged crank.

[Weehe]

The issue is OP has an m235i which has the forged crank, he would have to find an m235i motor which is a bit more difficult than finding a standard n55 which doesn't have the forged crank.

I was emphasizing how big of a pain in the ass it is to pull the pan while the engine is in the car. I didn't mean he needed a new engine.

[F87Source]

I was emphasizing how big of a pain in the ass it is to pull the pan while the engine is in the car. I didn't mean he needed a new engine.

I see, yeah it does suck to pull the pan. If is anything like on an sti there is so much sealant by the time you get the pan off it'll likely be warped and require a replacement.

[Weehe]

I see, yeah it does suck to pull the pan. If is anything like on an sti there is so much sealant by the time you get the pan off it'll likely be warped and require a replacement.

It's just the oil pan gasket and I'm pretty sure the pan is cast. So those would not be issues.

[bnks334]

he can honestly swap in any N55. Just needs to swap over certain components which has been covered in several threads in several other places...

Oil pan itself is not an issue. Clearance is. The subframe is in the way. It needs to be lowered to get the pan out and completely removed in order to provide enough working space to actually get to the bearings. Makes the job take a long time. not hard, but, lots of things to remove just to remove an oil pan.

[F87Source]

It's just the oil pan gasket and I'm pretty sure the pan is cast. So those would not be issues.

Yeah thats good to know, I haven't touched an oil pan removal on this platform yet but I've done alot of these jobs on sti's and I could never remove it without warping the pan.