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excess oil pressure after new breather 900

posted by  j.pelchat on  Wed Nov 16 12:37 CST 2016
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last visit: Fri Oct 24 07:02 CST 2014
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Excess pressure as diagnosed by a leak from cam seal and dancing oil fill cap. Replaced seal, still appears to leak. Oil puddling on water pump and seeping thru new oil cap gasket. Replaced seemingly clear metal flame trap with plastic. All hoses are clear and intact. Dug out old breather box, which had been cleaned 5 years ago. Replaced with new unit. Everything back together. Oil cap still dancing. Too early to tell if cam seal still leaks, but I'll bet it does.

What else may be the cause of high oil pressure? No, I have not measured the pressure
--
89 240 wagon, 94 940, 215K, 94 940, 141K








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    excess oil pressure after new breather 900

    posted by  Onkel Udo II on  Thu Nov 17 09:56 CST 2016
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    last visit: Fri Oct 24 08:50 CST 2014
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    Other than the potential of excessive blow-by (unlikely but it does happen) there are only a few items you did not mention but may have already done:

    Clean the vacuum nipple for the PCV system with a stiff wire or tiny drill bit. Often you will find it clogged but it also gives you chance the verify that it is in fact the brass nipple with built in restriction (it is hard, but not impossible to swap them).

    Check for other vac leaks NOT a part of the PCV system. Enough or big enough ones can reduce the available vacuum so much the PCV system becomes ineffective. Unlikely but still possible.

    Replace the oil cap seal.

    FYI, that plastic oil cap on your car will dance pretty much no matter what. unless you add some weight to it to approximate the old style metal cap.

    Stupid question, but is yours a turbo with a vacuum pump?








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      excess oil pressure after new breather 900

      posted by  j.pelchat on  Thu Nov 17 20:10 CST 2016
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      last visit: Fri Oct 24 07:02 CST 2014
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      Thanks for the ideas. The caps on my two other red blocks sit just quietly with a warm engine. On this one the cap dances wildly and oil spits out. Oil is also leaking, probably from the can seal and puddling on the water pump.

      I'll check the vacuum as you suggested. It is not a turbo.
      --
      89 240 wagon, 94 940, 215K, 94 940, 141K








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        excess oil pressure after new breather 900

        posted by  spook on  Thu Nov 17 22:12 CST 2016
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        last visit: Fri Oct 24 08:06 CST 2014
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        Dear j.pelchat,

        Hope you're well. At the heart of the crankcase ventilation system is the brass nipple, on the side of the intake manifold closest to the fuel injectors. If this nipple is clogged, no vacuum is supplied to the crankcase ventilation system, even if the hose - from the brass nipple to the flame trap housing - is clear. You might want to remove the brass nipple and inspect it. If it is clogged, it can be cleared with a drill bit (1/8" / 3.5mm, if I recall correctly).

        Further, are you sure that the hose - from the bottom of the flame trap housing to the top of the oil breather box - is seated fully on the top of the breather box?

        Hope this helps.

        Yours faithfully,

        Spook








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    excess oil pressure after new breather 900

    posted by  Volvo From Heck on  Wed Nov 16 12:50 CST 2016
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    last visit: Mon Oct 13 20:56 CST 2014
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    What you are describing is excessive crankcase pressure--not oil pressure. I'm sure you now the difference and just got the terminology wrong. How many miles are on this motor? Aside from simple wear of the rings and piston bores a broken ring or piston can cause this condition. -- Dave







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