88pioneer Posted June 16, 2010 Share Posted June 16, 2010 Just had a quick question about my oil pressure. Ever since i put my full gauges in, I noticed my oil pressure would hover around 60 psi at idle or on the throttle. My question is, is this normal pressure for the 4.0's to run at? Also, it is a HO, not sure if the Renix motors run at a different psi Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted June 16, 2010 Share Posted June 16, 2010 That completely depends on the condition of the motor and its oil!! With a fresh oil change, my MJ with just about 90K will never go below 45-50. Near the end of the oils life and in the heat of summer it will hit 40 @ idle. OH yea, I almost always always run a WIX filter. (NAPA gold) :D CW Link to comment Share on other sites More sharing options...
Eagle Posted June 17, 2010 Share Posted June 17, 2010 The factory spec is 13 psi (minimum) at idle, and 37 - 75 psi above 1600 RPM. That's for all the engines. In reality, most tend to idle around 25 to 30 psi and run at 50 to 55 psi at normal highway cruise (60 to 70 MPH). There should be a distinct drop when you stop and the engine speeds goes down to idle. But ... the factory gauge in my '88 XJ basically sits at 40 psi no matter what speed the engine is turning. It has to be the gauge, because I've replaced the sender three times and it made no difference whatsoever. It drops to zero after the engine has been shut off, but once started it's more of a GO - NO GO gauge than a pressure gauge. Link to comment Share on other sites More sharing options...
88pioneer Posted June 17, 2010 Author Share Posted June 17, 2010 ok, so sounds like something i shouldn't be too worried about, thanks for the answers :cheers: Link to comment Share on other sites More sharing options...
metrictonner Posted June 21, 2010 Share Posted June 21, 2010 65 psi is oil pump relief pressure. Pressure shouldn't get above this. Did you change the sending unit with the gauges? If the pressure doesn't drop as the thing heats up you might look into what sending unit your shiney new gauge requires. There is a difference between a switch (hi-low) and a real he-man's sending unit. Link to comment Share on other sites More sharing options...
88pioneer Posted June 22, 2010 Author Share Posted June 22, 2010 i did swap the sender, but i guess that could be a possibility Link to comment Share on other sites More sharing options...
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