M30 535ia Crankshaft bearing replacement

[Dash01]

Can the crankshaft and rod bearings be readily replaced on the M30 engine, with the engine still in the car? Or, must the whole assy. be removed for this procedure?

I understand that the engine can be jacked up ~4" and the oil pan removed for access to the oil pump, etc. In that case, are the crank and rod bearings reasonably accessible, and/or can the crankshaft itself be readily removed if it needs machining? Bentley is silent on this.

[Dave M]

Yes, the cranshaft can be removed from below, but I would encourage otherwise. If you're about to delve into that much work, one might consider the condition of the remainder of the engine and act accordingly. Why are you interested in replacing the main and rod bearings? How many km's on the engine? Are you burning oil? poor oil pressure? Compression/leakdown test results?

I guess what I'm trying to get at is, why not remove the engine (not that difficult), have a lot more to play, and do more than just the bearings (rings, hone, headgasket, block gaskets/seals, head freshen etc. ???).

I was very hesistant upon my first engine removal, but found it to be quite straight forward. Just take lots O' photos :D

Dave M

[Bill R.]

would have to get the front harmonic damper off and the front timing cover as well as pull the transmission so you could remove the flywheel or flexplate, at this point you would have been ahead just to pull the motor.




Can the crankshaft and rod bearings be readily replaced on the M30 engine, with the engine still in the car? Or, must the whole assy. be removed for this procedure?

I understand that the engine can be jacked up ~4" and the oil pan removed for access to the oil pump, etc. In that case, are the crank and rod bearings reasonably accessible, and/or can the crankshaft itself be readily removed if it needs machining? Bentley is silent on this.

[Dash01]

would have to get the front harmonic damper off and the front timing cover as well as pull the transmission so you could remove the flywheel or flexplate, at this point you would have been ahead just to pull the motor.


OK, same question about the rod bearings: Can they be changed with the oil pan off and the engine still in the car?

Car has occasional low pressure light at idle while coasting to a stop, and am about to put 20W50 oil in. Has newly rebuilt head, gasket, valve job, camshaft, 10W40 oil, filter, oil pressure sender, good anti-drain valve in oil filter housing, etc.. but still gets the occasional low oil pressure light after warmup. So, if the thicker oil does not cure this, the next step would presumably be oil pump and/or new bearings.