wat is the correct oil pressure at start up and when motor is hot????????
is it suppose to be the same pressure at all times??????????


when i start up my jeep its reading around 40-60, on cluster
i drive around town for about 20 mins it drops down to 20-30 when slowing down or stopping,
when accelerating it picks back up to 40-50,
and before turning engine off its at 10-20,

is this normal for cherokees or do i need to repair or replace sumthing......

just completed an oil change,filter spark plugs and coolant.........

any help would be good

92 4x4 jeep cherokee laredo 6cyl.........
dave

 

At idle it should be 13 PSI. Best to verify with a mechanical gauge. Our 2001 was nine at idle. We switched to Rotella 5W40 full synthetic which cured the issue for us. If you search this forum there are many oil pressure questions. Our engine is quiet and runs fine just has lower pressure probably main bearings are a little worn.

 

X2 high mileage engines will = worn main = low idle oil pressure

 

It would make sense that it begins to fluctuate once it warms up, because your oil is not as thick as it was at startup and therefore doesn't need as much pressure to pump it. As for what is "normal"? I really don't know, but it's something I've been doing a lot of reading about recently.

Most people I've talked to seem to think that they need to run heavier oil to keep their oil pressure higher, but THIS ARTICLE has totally challenged me. It's quite long, but broken down into manageable pieces and is very well written for average shade tree mechanics like myself. I really wish everyone would read it and let's try to have some dialog about oil weight and pressure.

 

Oil Pressure
At Idle Speed (600 rpm) . . . . . . . .89.6 kPa (13 psi)
At 1600 rpm & Higher . . . . . . . . . .255 to 517 kPa (37 to 75 psi)
Oil Pressure Relief . . . . . . . . . . . .517 kPa (75 psi)

Low oil pressure on high mileage 4.0L is typically a result of worn cam bearings followed by main bearings.

 

thanks guys for the info.............

so i would say my oil pressure should be good as for now........

13psi at idle



thanks
dave

 

At 139k mine runs exactly the same as yours. I did a bunch of searching on here and found that its about right.