nakedredneck

95 grand 4.0 injector upgrade, semi-cold air, 204000 miles.

when i first start up and drive the oil pressure is just fine, but after it is warmed up fully when i stop and it reaches idle the oil pressure drops all the way to 0, and unless i put it in neutral and keep the rpm's around 1500 the oil pressure will stay at 0. you don't hear the vavles knock or the usual sewing machine noise from lack of oil. just wondering if it might be the oil pressure sensor, or if i should drop the pan and replace the pump and pickup.

Bustedback

Replace the sending unit, it's cheap and easy to do. The oil pump does not make pressure, it only makes flow. It's the restrictions in the oiling system that makes pressure. low oil pressure is caused by worn bearings and excessive clearences.

ct67_72

pick up a cheap mechanical gague or borrow a pressure gauge and check the pressure to make sure that what you are seeing is accurate. If you still have 0psi hot, like stated above, it is because of excessive clearances, or possibly an oil pump pressure regulator. although I would imagine even cold you would have minimal pressure. How much pressure does it register when you first start it cold? With cold thick oil, even with the pressure regulator stuck it should make 30-40psi. if you have more than that its in the engine.

Xjclassic

Just curious... What should the psi be at on a normal i4.0?

jronald

AllData Says:

OIL PRESSURE
At Low Speed (600 rpm) 89.6 kPa (13 psi)
At 1600 rpm and Higher 255-517 kPa (37-75 psi)
Oil Pressure Relief 517 kPa (75 psi)

What weight oil are you using? At 200k, at it being summer, run 20w50. Its not going to hurt anything.

Ron