Crankcase filter oil return pressurized

[buckeyemtnman]

I have air pressure and lots of oil coming from crankcase to (yes, towards/into) crankcase filter.....what would cause this? When I first start the cm871 in the morning, there is no major blowby at bottom of blowby hose that hangs down below oil pan, and no pressure/oil coming from crancase side towards/into crankcase filter housing. But if I release tractor brakes and move forward 10 feet and set my brakes, then I have major oil coming from blowby hose to groud and pressure/oil pushing into crankcase filter housing from the oil drainback tube.....any ideas? Is it my air compressor? I also have oil below my air dryer when it purges.

[Rawze]

First of all, any buildup of crank case fumes on an ISX engine will quickly wipe out the overhead cams, because any pressure buildup will cause restricted oil flow to the top end and starve the cams of oil. In fact that is one of the biggest reasons that the ISX has cam issues.. lack of proper engine maintenance and neglect of regular servicing of the crank case filter.

That engine should never be allowed to have any kind of crank case pressure buildup ... meaning that the crank case filter needs regular replacements and not be neglected.. or better yet.. to install a maintenence-free crank case filter for it and be done with it...
ref: http://rawze.com/forums/showthread.php?t...50#pid8950

If the crank case relief circuit cannot keep up with the blo-by, and it is not clogged up, etc ... then your engine is likely in need of an inframe. - How much blo-by does the engine make?.

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As far as oil getting into the air system,... have you checked to see if the cac piping going into the intake manifold is not wet with oil on its insides??. Checked to see if the turbo is not seeping oil out into the intake?