My JD 757 zero mower blows oil out of the dipstick hole .Tried a new dipstick,its still coming out and getting blown by the fan on the hot muffler?????????
I know this is an old thread but that's usually a sign of a blown head gasket.
What happens is compression from the cylinder is leaking into the crankcase building up pressure, that's why it blows out the dipstick tube when it's running.