Concerned about oil pressure

[efosterw]

My 96 XJ's pressure is 40 at idle and 60-75 when driving. Oil pressure is supposed to go down when driving, right? What would cause it to be high? I'm learning about such mechanical stuff - newbie here.


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[abebehrmann]

My 96 XJ's pressure is 40 at idle and 60-75 when driving. Oil pressure is supposed to go down when driving, right? What would cause it to be high? I'm learning about such mechanical stuff - newbie here.


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No need for concern. That's pretty good oil pressure. It's normal for the oil pressure to go up when you're on the gas, both of my 4.0L's are pretty much the same.

[efosterw]

No need for concern. That's pretty good oil pressure. It's normal for the oil pressure to go up when you're on the gas, both of my 4.0L's are pretty much the same.



Thanks! I'm figuring out what "normal" is for my XJ. I really appreciate your feedback on my posts.


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[bluedragon436]

Yeah, it can be sometimes a bit nerve racking to see the pressure moving around quite a bit.. I went out on the trail @ a local Jeep club's property a few months back, and while running I happen to look down to check my coolant temps, and noticed the oil pressure was quite a bit down.. I was pretty worried about it, but once we started moving again it came back up and then fluctuated up where it normally is during day to day operation with stop and go traffic..

[denverd1]

you have good pressure. More RPM = higher pressure, oil pump is directly connected to the cam.

pressure sending unit are common failures on these. so DO NOT get alarmed when you're out driving around and buzzer goes off and you have no pressure. Mine seemed to slowly fade before it stopped working.

[Tbone289]

My 96 XJ's pressure is 40 at idle and 60-75 when driving. Oil pressure is supposed to go down when driving, right? What would cause it to be high? I'm learning about such mechanical stuff - newbie here.


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Those are normal pressures, but it is possible that your sending unit is going bad. Mine went bad and started showing 40 PSI at hot idle rather than the 20 PSI it had always showed before. Replacing the sending unit brought it right back to the normal range for me.

When you turn your ignition on (not running), your gauge should show 0 PSI. When mine went bad, it would show around 20 PSI. So, basically it would always show 20 PSI higher than actual pressure.

[efosterw]

Those are normal pressures, but it is possible that your sending unit is going bad. Mine went bad and started showing 40 PSI at hot idle rather than the 20 PSI it had always showed before. Replacing the sending unit brought it right back to the normal range for me.

When you turn your ignition on (not running), your gauge should show 0 PSI. When mine went bad, it would show around 20 PSI. So, basically it would always show 20 PSI higher than actual pressure.



Great info! I'll check it out. How hard is it to change a sending unit for a newbie?


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[prerunner1982]

My oil pressure gauge would read weird when my sender went out as well.

It is not hard to change, it is located just above the oil filter on the passenger side of the engine. Disconnect one electrical plug and use an adjustable wrench to loosen the old one. Reverse order to install.

These are also common to break when changing your oil due to their proximity to the oil filter.

[drakan1908]

My oil pressure gauge would read weird when my sender went out as well.

It is not hard to change, it is located just above the oil filter on the passenger side of the engine. Disconnect one electrical plug and use an adjustable wrench to loosen the old one. Reverse order to install.

These are also common to break when changing your oil due to their proximity to the oil filter.One day I was changing the oil in my Grand and knocked the wire loose. I got in and started the motor...no oil pressure...talk about freaking out. Cut it off started looking around, counting empty quart bottles, went to pull the dipstick and spotted the connector hanging there. Whew what a relief. Lol

Sent from a van down by the river

[efosterw]

One day I was changing the oil in my Grand and knocked the wire loose. I got in and started the motor...no oil pressure...talk about freaking out. Cut it off started looking around, counting empty quart bottles, went to pull the dipstick and spotted the connector hanging there. Whew what a relief. Lol

Sent from a van down by the river



Dude... the ambulance would be coming for me!


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[Tbone289]

Great info! I'll check it out. How hard is it to change a sending unit for a newbie?


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Very easy.


There's not much reason to change it unless you know it's not reading right. Hook up a mechanical gauge and test, or at least check for proper zero reading with the engine off.