rotary valve oil being pushed out the reservoir bottle on 582

[1avidflyer 1983]

A friend of mine is getting oil pushed back out of his rotary valve oil reservoir on his  gray head 582.  He did remove the oil injection pump, not sure if that would make a difference.  No evidence of coolant mixing with the oil either.  I would think if seals were leaking at the rotary valve, oil would get sucked into the engine rather than the opposite condition.  Any ideas?  JImChuk

[saskavid 47]

Is it an inverted mounting condition? the level in my reservoir does increase a bit when the plane is at operating temps but retreats when it cools back down but isn't forcing it out the top of the bottle....

[1avidflyer 1983]

Not inverted.  Plugs up on a Kitfox 2.  JImChuk

[Dusty 126]

Perhaps ground run with the cap off and observe. May be expanding by foaming . If so change to a different oil as some have better anti foam. Bubbling is bad but as suggested oil may possobly be sucked by the crank seals rather than case pressure blowing.

[1avidflyer 1983]

He put a clear hose on the top of the reservoir and ran the engine so he could see what was going on.  Oil was coming up in the hose.  Strange one for sure.    JImChuk