What is the purpose of the oil extraction pump?

[ninsei]

hi. Just replced Cyl 4-5-6 oil extraction pump cause the old one was leaking. Now my oil pressure seems higher than normal (or is it my imagination): engine at normal operating temp, revs at a steady ~3K RPM, pressure gauge stays at ~4.5. I thought is would normally be at about ~3 at that point. 'wondering if the new pump is defective, or if that thing has nothing to do with oil pressure.

[wvicary]

The extraction pump is not the main oil pressure pump, it remove excess oil from the cylinder head area and returns it to the main sump for the pressure pump. Oil pressure changes with engine temp so I think you have nothing to worry about.

[ninsei]

The extraction pump is not the main oil pressure pump, it remove excess oil from the cylinder head area and returns it to the main sump for the pressure pump. Oil pressure changes with engine temp so I think you have nothing to worry about.

Thx. There is also a diagram that explains it all in the "Service Information Book", available to members.