Does this seem like a fairly complex system, or is this "normal" in other engines, too? These are the components that regulate oil pressure in my V6 Audi engine: The oil pump is capable of putting out 200 psi. Oil pressure relief valves: - 16 bar (232 psi) in oil pickup assembly - 11 bar (160 psi) safety valve, only opens at high RPM and cold engine temp - Pressure relief valve in the oil pump - one pressure valve on each head. Those control top-end oil pressure. - Two oil check valves in the steadying chamber (under the valley pan), but those don't really do much in terms of pressure control; they just keep oil in the lifters when you shut the engine off. There's also some pressure control done by the head gasket - each one has a finely-tuned obstruction to oil flow that maintains oil pressure in the engine block when the oil pressure relief valves are open.