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Oil leak help

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  • Oil leak help

    I noticed the M, which has been pretty much leack free for me until now, was dripping oil, from the foward tip of the bell housing. I noticed it after the last auto-x, so the car was being driven somewhat hard. I've only had the time to give it a look for 10-15 minutes, but it looks like there is a small pool of oil under the starter. There is a plastic (?) tube that looks like it might be some sort of oil vent? Its marked "BMW" & "PURALATOR", and it looks like it has hoses coming from the driverside of the oil pan, under the plenum, and maybe other spots? Is this a part that leaks, or is it most likely coming from one of the hoses? Or do you think I am just completely wrong? I'd like to order some parts so I can park the car in the driveway again:drive:



  • #2
    There are just so many possibilities, it is really hard to say. Oil dripping from the front of the bell housing could be RMS, RMS carrier, front transmission shaft seal, upper oil pan, rear cam box cover, cam box to head joint.

    Best advice is to really clean and degrease the engine, go for a short drive, then come back. With a flashlight, inspection mirror, etc really contort yourself and carefully look for oil to see where it is emerging from.

    My ugly experience with these cars is that if you assume it is coming from some logical spot without really finding out, you will usually be wrong.


    • #3
      As a rule of thumb , you have to track the leak from the lowest point on the engine/bell housing, upwards and quite often forwards.

      On the starter side of the engine you have the oil pan gaskets (Top one is cork) crankcase ventilation lines, some of which return oil to the pan, plus you have recirculation back into the intake tract. This then potentially involves the various joins of the intake as potential oil leak sources. The highest point of a potential leak s on this side of the engine is the cam cover gasket and the vent hose that routes down the crankcase ventilation plumbing.

      On the front of the engine you have the oil pan gasket, crank front seal, the profile gaskets of the timing chain covers, the cam drive caps, the distributor , and the cam case cover.

      On the hot side of the engine(and it is tilted to this side), you mainly have the timing chain tensioner with the touchy crush ring, and the cam cover.
      On the rear you have the oil pan gasket, the RMS, and the camcase end cap gaskets with the camcase cover.

      If the lowest point of the leak is below the block, trace up and forwards. If you're not sure of the oil type, and the leak is on the bell housing, you'll have to pay attention to the steering rack and transmission, as well as the PS reservoir.

      You could take the car to a shop, have them add some UV reflective dye, wash the engine, and black light the drivetrain.