werminghausen
12-24-2009, 01:19 PM
For those of you who have a M50 vanos 94 oilfilter housing any experience oil leaks on the driveway- This leakage might be caused by a leaking oilfilter housing. The oilfilter housing on the 94 and may be some other years too has 2 caps on the backside of the housiung facing the intake manifold. These caps are secured by a wire snap ring and sealed by an O-ring. This Buna O-ring is old and hard and may be cracked after years - and leaking oil. It is hard to see at all. If you remove the plastic duct for the alternator you can see one of the caps with a mirror. Oil is leaking down and dripping down at the drivers side of the oil pan.
I was loosing like 1 quart per 1000 miles, not too much but these leaks can get bigger any second. If this o-ring fails completely it can get serious for the engine if you don't notice immediately.
repair: You take off the alternator (disconnect battery and remove shroud and fan before) , loosen the PS pump, disconnect oil pressure sensor cable and then you can remove 6 bolts for the oilfilter housing. Remove oilfilter housing. On a workbench you remove the wire snap rings and take off the caps. Remove the old and hardened o-rings. Put in new ones (use 22 x3mm o-rings, 22 x2.5mm ones are too small and they will most possibly leak afterwards- guess how I know this).
It is quite difficult to put these o-ring in correctly because there is no groove for them. It took me 3 courses until I did it right.
First time I used the 22 x 2.5 - was leaking, second time I put in the 22 x3 but did something wrong- one o-ring was set incorrectly and it leaked slightly
, third time i installed 22 x 3 correctly, did a pressure test with air and since them all is fine. The pressure test with air is a good idea-100 PSI move the o-ring in the correct position and makes sure that you do the job just once.
I have machined a steel plate and connected a AC hose for pressure testing.
If someone needs advice please let me know.
I also have a good oilfiter housing to sell if you are unsure about replacing these o-rings.
Martin
I was loosing like 1 quart per 1000 miles, not too much but these leaks can get bigger any second. If this o-ring fails completely it can get serious for the engine if you don't notice immediately.
repair: You take off the alternator (disconnect battery and remove shroud and fan before) , loosen the PS pump, disconnect oil pressure sensor cable and then you can remove 6 bolts for the oilfilter housing. Remove oilfilter housing. On a workbench you remove the wire snap rings and take off the caps. Remove the old and hardened o-rings. Put in new ones (use 22 x3mm o-rings, 22 x2.5mm ones are too small and they will most possibly leak afterwards- guess how I know this).
It is quite difficult to put these o-ring in correctly because there is no groove for them. It took me 3 courses until I did it right.
First time I used the 22 x 2.5 - was leaking, second time I put in the 22 x3 but did something wrong- one o-ring was set incorrectly and it leaked slightly
, third time i installed 22 x 3 correctly, did a pressure test with air and since them all is fine. The pressure test with air is a good idea-100 PSI move the o-ring in the correct position and makes sure that you do the job just once.
I have machined a steel plate and connected a AC hose for pressure testing.
If someone needs advice please let me know.
I also have a good oilfiter housing to sell if you are unsure about replacing these o-rings.
Martin