M54 Engine Lost Compression on Cylinder 6

[Effduration]

Sorry to hear - Did you ever figure out what caused the loss of compression in cylinder 6?

[Auto Parts Guy]

I did not. For it to still have some compression (12psi) I would guess the rings went. It sucks. The guys that bought the hood and stuff had a nice titanium Silver 6 speed! So at least some of the parts went to a good donor.

[Effduration]

Originally Posted by BimmerBreaker

Ive never seen a single documented case of an M54 ingesting a DISA pin............

The amount of time spent thinking about it and checking other random things at this point could have just gotten the engine out. It's about a 5-6 hour job. Faster if you have a lift. Hardest part on an X5 is getting it over the radiator core support due to how deep in the engine bay it is. With a lift you drop the subframe and lift the car up over the engine/subframe assembly (the inverse of how they are installed at the factory)

I wonder how many people suggesting you remove just the head have actually removed and reinstalled an M54 head before.

It seems easier to just remove the head because it's only removing "one part" but in reality I think it will take more time and end up being more complicated compared to pulling the engine. Having the engine out will also give you a chance to re-seal the rest of it for new gaskets all around to end up with a nicely refreshed engine.

I am not disagreeing with the recommendation of swapping the whole engine here.

But I was one of the people suggesting OP remove the head in this situation, and I still think it was also a reasonable way to go, particularly if OP does not have a lift (not sure if that is the case).

I don't have a lift, but I have done in-car M54 head replacements about six times...E46, E39 and twice on E53's... There is really good access on an E53... I have also done a couple of engine replacements.

[Auto Parts Guy]

I've got a lift but man that's a lot of work with no guarantee that I'll be able to salvage the engine. And to do it on a vehicle that has 214k miles and very little value to most and still wouldn't pull a camper was kind of the reason I decided to part ways. Just replacing those plastic coolant lines under the intake was a PITA (intake removal was the PITA part) that I didn't want to do again, much less removing the head. It basically came down to time and end result and value for the money for me. Hopefully I can get some of my money back with a high level part out.