2001 Ford Expedition 5.4 sohc. I have an aftermarket oil pressure gauge. I changed the engine oil recently. I know have a vaccum when I pull the dip stick or oil cap. It's a constant when the engine is running.


What might cause this? I think the prv in the pump could be stuck shut??

I noticed it thanks to the real gauge. I see a constant 40psi at all times and it dosen't change much with rpm. It can't be good?? Ie like pulling the oil out The journals and galley

Oil is 5w20 with a Napa gold filter wtf is happening??

 

The crankcase is connected to manifold vacuum through the PCV. Air is supplied to the crankcase from the air intake behind the air filter to the opposite side valve cover. So a small amount of air should be circulating through the crankcase when there is manifold vacuum and it is highest at idle or during low throttle conditions. The air inlet side may be plugged.