In the last week or so I've noticed the my oil pressure is lower then normal when the jeep is warmed up and idling but when I drive it goes up to 40 or a little above. Today I noticed when my jeep was at idle in a drive through the oil pressure was low again and my jeeps temp was about 210 with the heater blasting and the outside temp was about -2 and my jeep only gets to about 210 if I'm using 4wd to wheel or if it's in the summer. About a year ago I did change the water pump and the thermostat so I'm just curious what other people think. Is this a big deal and if so what should be the first things I check to get it working right?

 


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Both look normal to me. Minimum acceptable oil pressure is actually 13psi.
If you want you can verify both with a mechanical gauge at the oil filter adapter and an inferred thermometer at the thermostat housing.

 

The idle pressure is usually around 40 at idle so I was just wondering since it's lower now but other then that it seems to be running normally.​​​​​​​

 

evidently you are running hotter than before, correct? check your gage. also check you oil pressure gage. maybe they are suffering from faulty reading?

As a general rule of thumb, you want a minimum of about 10 psi oil pressure for every 1000 rpm when hot. at 4000 rpm, a minimum of 40 psi. note this is minimum value. I often have 50 to 60 psi at 4000 rpm when my temp is near 190 to 210 F. a little less pressure as she gets hotter, a bit more when cooler engine temp.

note that in extreme hot condition a higher oil weight is needed verses sub zero (F) condition when lighter weight oil maybe needed. Consult owners book for recommend oil weights verses temperature.

 

Mine has low oil pressure at idle when hot think it it was 9 psi. Been like this for 6 years and have verified it with a real pressure gauge Running down road at 70 mph its around 60 psi. I let it be as doesn't get loud figure hell its a tractor motor it will be fine .

 

That is good pressure at idle.