Oil filter housing check valve

[Northern]

I have an M52 that I want to put an M50 housing on. Mostly so I don't need a massive socket to change filters and can use my stockpile of M50 filters.

When I removed my M52 housing, it has a check valve that the M50 manifold doesn't.

m52 vs m50 housing by e30-V, on Flickr

m52 filter housing by e30-V, on Flickr

This thread confirms that it is a check valve to stop oil from flowing out of the oil gallery/filter/etc when the car is off. I can imagine this would do a lot for the life of the engine...

So why does the M50 housing not have one. S54 housings don't seem to have one either, but they have a different pump that may or may not have a check valve built in.

E36 M/S5x seem to share the same pump except for some very early ones, and they don't seem to have an internal check valve on the pump, so why would some have this, and some not?

Is it safe to run the M50 housing on this engine?

[328ijunkie]

Open the m50 housing and look inside ;) no idea why they moved it.

[Northern]

That makes a lot more sense than every engine but the M52 not having one...

Thanks Dave!

[Rook12V]

Interesting, I just put my S50 OFH on the engine this weekend and it most certainly does have that check valve, in the same spot as your M52 does.

[Bmwdayz]

I have a z3m s52 in my e30 and the oil housing is the same as the s54. I was wondering the same thing because I didn't see a check valve. So I asked around to find out if it's normal and figured it would be ok so I ran it. It's been fine for a year now with no issues.

[328ijunkie]

M50/S50/S52/S54 OFH all have them inside underneith where the oil filter goes...