pet1

I have an 02 grand cherokee 4.0 and I'm not sure if my oil pressure is stable. I'm assuming the gauge reads 0,20,40,60,80. When I first start the car cold it reads about 60. When I drive off it would go to about 70 then eventually around 50 and 60 at idle. I'm not sure if it's going up too high. It's never reached the H. But as I said it does hit about 70 or so after I drive off. Thank you for your help.

pet1

Any ideas? I'm a little worried. I want to make sure nothing bursts or worse the engine explodes. I don't have time to take it to a shop until next week the earliest. Please, that would be much appreciated.

Garrett S.

Its probably just the sending unit reading high because of a bad connection or age. I wouldn't worry about it.

pet1

When I first start the car it goes to about 65 or 70 and like I said it eventually goes to just above the midway mark. Is this ok? Cause it's about to get cold and I don't want anything to happen. Am I reading the gauge right? Not sure where the numbers are. Thank you for responding. I really appreciate it.

Garrett S.

Yea around the middle is where it should idle warm. Those gauges usually just give you an idea of whats going on, they were never very accurate. I only ever worry if it gets low.

dave1123

Look at the sensor. If it's leaking or there's oil in the plug, replace it. These things aren't just a diaphragm thing anymore. They have a piezo crystal and a printed circuit in them now. Actually somewhere around mid 02, they changed them to being just a slide switch that supplies a 40 lb signal PERIOD! If there's pressure it'll read 40 psi anytime the engine is running regardless of what it really is. I asked a Jeep parts guy why they just didn't install an idiot light instead and his answer was people like to see gauges and if it wasn't there, people wouldn't buy jeeps anymore or be less inclined to. Makes sense in a marketing sort of way. SO if you buy one, ask for one from a 2000. NAPA only stocks the new one. Ask me how I know this. Check out wjjeeps.com

BTW, My 2000 WJ 4.0 holds 40 psi at idle hot, 50 on cold startup, and 55 at 65 mph. This with 243K miles on it. I even have a cracked piston in #5.

pet1

Thank you. So now it's going directly to the H when I start the it. Should I be worried now? I was also told there was a small leak in the rear seal. Not sure if this has anything to do with it. I have to take a family member back and forth to the hospital over the next few days and and very concerned.

Kymasabe

I'd drive it. There are very few situations where a motor will increase oil pressure as it wears. As mentioned earlier, is most likely a sending unit failure and not reading correctly.

Garrett S.

If it makes you feel better you could get a universal gauge at the parts store and see if the stock gauge is accurate. Still, like everyone said, I wouldn't worry about it.

blueseasons

pet1. Same answer to the same question you asked on another Jeep Forum. Instead of "worrying" about it. Change out the sender already.

pet1

I wish I could. But the shops are closed and I simply don't have the tools to do so. I certainly don't want to turn something easy into something worse. I really appreciate all the input. Thank you all very much.

pet1

Swapped out the sensor. Fixed.