Volvo AWD 850 Forum

INDEX FOR 10/2025(CURRENT) INDEX FOR 3/2016 850 INDEX

[<<]  [>>]


THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD




  REPLY TO THIS MESSAGE    PRINT   SAVE 

Oil Trap problem? 850 1994

I have a 94 noon-turbo 850 with 278k miles that has oil leaking out of dip stick tube. My guess is that I have excess oil pressure and the only place for the pressure to go is up the tube.

My flame trap is clean and vacuum lines look OK. I've seen some postings about an oil trap. Does this sound like an oil trap problem?

Any ideas? The amount of oil isn't to bad, maybe a quart in 1500 miles. But am concerned about why oil would be coming from where it is. Also don't really care for that oily smell.

Any ideas?








  REPLY TO THIS MESSAGE    PRINT   SAVE 

Oil Trap problem? 850 1994

Any chance coming from cam shift seals?








  REPLY TO THIS MESSAGE    PRINT   SAVE 

Oil Trap problem? 850 1994

You can verify an excess of pressure by loosening the oil filler cap and seeing if it will rest on the engine while it is running. If the cap wants to lift up much at all, there is positive pressure which should not be there.

I think you can diagnose the oil trap in place. There are 4 places the pressure can go (assuming you don't have any blown oil seals). 1) Dipstick, 2) Vapor tube that runs from the fitting on the cylinder head (under the sparkplug wire cover) to the oil trap 3) Vapor tube that runs from the oil separator to the flame trap 4) Passage through the oil trap to the crankcase.

I would remove the tube from the cylinder head and plug the end of it. Also remove the tube at the flame trap. Blow a little air thru the tube at the flame trap end. If the path through separator to crankcase is not clogged, this air should escape out via the dipstick, oil filler cap, or the fitting on the cylinder head. Conversely, if you close the oil filler cap, the fitting on the head, and the dipstick (blocking all exit via the crankcase), air should be able to go out through the tube which had been on the cylinder head.

I once had trouble with overpressure that remained after cleaning the flame trap well. It turned out the tube from the oil sep to the flame trap was blocked with crud (sitting an inch or 2 back from the flame trap end). Also as others have pointed out, the small line from the flame trap housing that goes direct to full manifold vacuum can clog badly.

I guess these tubings can get quite brittle over time so they could crack when handled.








  REPLY TO THIS MESSAGE    PRINT   SAVE 

Oil Trap problem? 850 1994

Thanks for the reply.

Wasn't sure which was the tube at the cylinder head you mentioned - is that the one to the vacuum tower?

I did take the large tube from the flame trap housing and blew into it. No air can out of anywhere I could tell and pressure built up. Pulled dipstick and air came out that way. Took off oil fill cap and air came out that way.

So if I understand you, there is the tube at the cylinder head that I should have had air flow though? Can you help me identify this tube better?

Thanks,

Bob








  REPLY TO THIS MESSAGE    PRINT   SAVE 

Oil Trap problem? 850 1994

Look under the plastic spark plug wire cover. It runs from the top of the head to the oil trap between branches of the intake manifold. It is about 1.5 cm in diameter outside.







<< < > >>



©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.