With engine running I have pressure on it.
Just so we understand, you removed the pipe plug and your getting pressure coming out of that port?
If that is the case, pressure in the crankcase is created from blow-by from the piston rings. The rings don’t seal perfectly so a little leaks by creating the pressure. The crankcase is vented by the road draft tube or
PVC PCV system that was used on big trucks. Your road draft tube or
PVC PCV system may be clogged with sludge.
In addition, the oil fill cap should also be vented allowing fresh air to replace the crankcase blow-by being exhausted by the road draft tube. That could also be plugged.
