The oil pressure really never fell below 20 and would always rise back to 40 with higher RPMs. I did notice a few times prior to the head gasket change though- there were times the oil pressure went to 60 when cold sometimes higher but would always drop back to 40. It never went all the way to 0. Now when at idle the pressure is 0 and at 2000 RPMs it is 20psi. On the highway at 2500 3000 rpms maybe 30psi.

Is it possible that when the oil and water were mixed it could have damaged the pump?

1990 Toyota 4x4 22 RE. My life!!!! My project continues! Always. I'm convinced it is an addiction. Still Running great after a year.

2000 Jeep Cherokee Sport. STOCK version.