Poor seal on new crank cover gasket

  • The bolts seem to bite into the alloy before they have compressed the rubber spacers sufficiently. I assume that's the whole problem. Is there any reason I can't shim the spacers with washers just for now?

  • Quote from "JoelB"

    The bolts seem to bite into the alloy before they have compressed the rubber spacers sufficiently. I assume that's the whole problem. Is there any reason I can't shim the spacers with washers just for now?


    The cover should sort of float on the rubber gasket and the rubber seals on each cover screw. There is a flange on each cover screw that is supposed to touch the engine case. This is how you establish the correct torque on each screw (and don't over torque them!). If the rubber seals on the screws are fresh and you are using a fresh gasket, torque each screw to the specified value (what is it, 5 or 7 Nm?) then you are fine. If the rubber seals on the screws are worn, they will leak of course. They are a cheap enough part to keep a pile in a drawer on your work bench.

  • The screws must be the problem. I'll get a box of them when I can, (I live hours away from my nearest dealer).


    It's been fun though. Pan started leaking due to a change in season so I got a new gasket, which leaked badly dumping oil over my foot. Then I packed the screws up with a washer each, and it didn't occur to me that they were sealing the holes and the oil quickly drained. Then I mounted the washers behind the rubber seals but the one near the coolant hose didn't fit well and the crankcase pressurre helped to pump it out of there so fast, that I seized the engine due to a lack of oil. My warning light didn't even help me.


    By the side of the road, I managed to snap that bolt in its hole. I managed to find a bolt that I used to bite into the cover casing but it didn't help and I needed to buy 8L of oil to ensure I could make it home safely. I'm determined to stop that from happening again.


    I removed the cover and extracted the broken bolt. I have a few spare old ones. The extra pressure from the washers had also damaged parts of the new gasket, but I thought it would be repairable so I cleaned everything for the umpteenth time and packed it with threebond. I also sealed the bolt rubbers. After just 10km riding in the dark I felt the engine begin to labour and switched it off just before it was going to seize again from lack of oil. The cover was hissing due to the crankcase pressure escaping.


    This time I'm going to dispense with the gasket and use Permatex gasket maker silicone. Then, when I see my dealer I'll get a box of screws and a new gasket, but I'll see how well the silicone holds up.

  • You may also be having another issue if you crankcase is being "pressurized" as you say and pushing oil out.
    Ideally the crancase should be in a vacuum not a positive pressure.
    Check you vacuum lines that run behind the TB's and especially the one that goes into the left rear of the block behind the airbox.

  • The cover shouldn't leak "due to a change in season". In fact, in 27 years of ownership and 284,000 miles I have never seen a crank cover gasket leak. Where I live we definitely have a change of season. This morning, as it has been for weeks, it was well below freezing on the ride to work.
    I have to replace the rubber seals on the cover screws periodically as they start to weep oil, but aside from that these gaskets are of a very high quality and last forever. As Scott Anderson mentions, you have another problem causing your crank case to pressurize. This needs to be addressed first or all you are doing is spinning your wheels.

  • I think you guys are on the right track...and here's why ;)


    This morning I pulled my crank cover again and replaced the gasket with silicone copper gasket maker. I used a little on the grommets as well. The instructions suggested an hour might be the minimum to wait so I gave it almost two. This performed well for about 15 minutes then it let go and oil was everywhere again.


    After some time to think, I came up with a few reasons to prove to myself that maybe the crankcase shouldn't be so highly pressurised. Anyway, I found an old bottle top by the side of the road, and I ran a little rag around it so that I could screw it firmly into the oil filler hole, but I left a gap in the rag so there was a breather hole. Suddenly the leak stopped.


    Thanks guys, and Scott I'll check those hoses tomorrow. I wonder if I could ask just a few more questions.


    I'm thinking this may be a head gasket or a damaged bore. Does this sound fair enough?


    What is the effect of the crankcase being pressurised... because I remember reading about a problem tuning the motor if the crankcase isn't sealing right. Might have been mixture? Maybe I should look this one up myself. Anyway it's just that if it is a head gasket then I might plan to use it a little longer until I can get around to it.


    And, have I caused anything nasty by allowing the motor to seize without oil?

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