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This is a DIY for removal and replacement of the manual transmission clutch for the E90 with the N52 engine. The procedure for the N54/55 is mostly the same except maybe for the transmission mounting bolts. This DIY is for experienced home mechanics with a decent set of quality tools. If you are a novice at car repair, the scope of a clutch replacement is probably beyond your skill set and tool kit. The use of air impact tools is highly recommended for some procedures. I used a two-post automotive lift to do this work. The rear main seal requires use of special tools and sealants (only available from BMW). I ended up not needing to replace the rear seal, but I provide the procedure I was going to use to replace it. The Bentley repair manual goes into great detail on how to remove and replace the seal, so I highly suggest you use the Bentley for the rear seal. I sourced most my parts from Turner Motorsports. They were very helpful. If you buy from Turner, make sure you get the correct flywheel. Their website lists the flywheel for the 2006 E46 325ci, not the E90 N52. If you plug in the E90 flywheel part number from realoem.com, turner has the correct part.

I do recommend you use the Bentley repair manual as reference with this DIY. This DIY attempts to “fill in the gaps” where the Bentley has no information.

The attached Adobe is 19 pages long. There is a lot of detail to go over. A few guys have done the clutch on jackstands, but I can't see doing it on stands; getting to the top bell housing bolts is a PIA. On stands you'd have to have a helper sight-in the tools to get to the bolt heads.

If your oil pan gasket is leaking, I highly recommend doing the pan gasket before or just after the clutch. The rear of the oil pan protrudes into the bell housing behind the flywheel. The clutch pressure plate has cooling fins built into it that make enough airflow in the bell housing to spread engine oil all over the place; it makes a serious mess.

There is much debate about replacing a non-leaking rear main crankshaft seal. The several professional mechanics I know all say if the rear seal is not leaking, regardless of mileage, then leave it in place and do not replace it. The thought here is if you replace the seal, there is a 50/50 chance the new seal may develop a leak. With the N52, the seal requires special tools for removal and installation. I could not locate the tools on line anywhere (in late 2015). I'm sure you can rig some special tools and replace the seal, but if the seal is not leaking, I recommend leaving it alone. Also, the seal needs special sealants and primer chemicals to correctly install it. The products are from Loctite, but their website does not list them. I found the primer and sealant is only available from BMW and costs about $80 for the kit.

Finally, my car had a driveline vibration related to engine RPM. At high RPM it made an awful noise and vibration. At idle the vibration made for a lumpy idle that kind of feels like a constant misfire. I confirmed the vibration was the dual-mass flywheel being bad, which is why I was replacing it. So if your car has RPM related vibrations and no SES light, it is probably the flywheel. BAV Auto has a few articles on the issue (I discovered later) that indicates the dual-mass flywheel can indeed go bad and cause vibration. There are single-mass flywheels that you can replace the dual-mass with, but I wanted to remain stock. I've read where the single-mass units up the engine power a bit because they are significantly lighter than the stock dual-mass unit, but the tradeoff is driveline vibration, which is what I was chasing down to solve.

I hope this DIY saves you time.