1999 Jeep Laredo 6 cyl Four Wheel Drive Automatic 170K miles
I have never had a problem with the oil pressure in all the years I have owned this Grand Cherokee. I change the oil and service it regularly. Yesturday I notice the gauge was reading around 60 at an idle and between70 and 80 at higher RPM's. I stopped and picked up some SeaFoam additive to add to the oil incase the problem was a gummed up pressure release valve. This morning the pressure seemed to run even higher at high RPM's at 80 the whole 50 mile trip to work. How long should I give the SeaFoam to work before I can say that the pressure valve is probably shot? Any other ideas as to what might cause this to happen? I have heard that dropping the pan to change the pump and valve is a total nightmare!
I would not wait to see if the can of stuff does anything, fix the problem properly, the high oil pressure will cause a seal to fail, hopefully not the rear main, so get it attended to ASAP.
December, 28, 2007 AT 8:50 AM
I have to hold off until at least tomorrow before I can look at this problem any deeper. I am going to rent a mechanical oil pressure tester and see if the problem may lay in the sending unit or the dash gauge. If both of those are funtioning properly what would you expect to be the problem - Oil pump, relief valve?
December, 28, 2007 AT 4:19 PM
Do the test, then you know where you stand. The pump creates the flow of oil and the relief valve controls the pressure, if the pump was inefficient the pressure would be low, the valve is where the problem lies,
January, 3, 2008 AT 8:59 AM
I brought the Jeep to the garage yesterday and it turned out to be the sending switch. Thanks for all of your advice.