oil tank pressurizing valve

oil tank pressurizing valve

oil tank pressurizing valveclick for a larger image
A typical dry-sump lubrication system that shows a sump and oil tank-pressurizing valve.
A check valve in the oil tank vent system that maintains an air pressure normally between 3 and 6 psi on the oil. This ensures that oil is supplied to the engine-driven oil pump under positive pressure at all altitudes.