I recently just grabbed at 98 cherokee with 215k miles this last week. I noticed while driving not to long after that at an idle the oil pressure would drop to the second to last line on the low side and sit there till I got under load, after that it would return back to 40 or the middle mark.

I'm not familiar at all with anything jeep related and I'm curious as to what it could be. I heard I need to replace the oil pump. I hope it's nothing serious and going to break the bank.

 

That's normal oil pressure when warm. Spec is 13psi at idle and 10 psi per 1000 rpm. The lines from left to right are 0, 20, 40, 60, 80.

 

Normal. My 98 does the same thing. The gauge may not be 100% accurate as well.

And since you're new to jeeps, don't run the cheap Fram filters in these things. They will definitely affect your oil pressure. Found that out first hand.

 

This is from the other day shortly after the oil change.

 

See my previous post? If you put a fram on there, get it off.

 

The filter is whatever valvoline installed. But thank you guys

 

A quick change place?

Junk filter then.

 

Ditto on the oil filter, its probably junk. The pressure is fine, but could be higher. My 2000 XJ idles at 40psi, goes up to 60psi when hitting the gas.

 

Lucky turd. Mine sits right where OPs does and I run delo 400 xle and a Baldwin extended volume filter.

 

Pressure doesn't equal flow. And type of oil and filter affects everything lets face it. When I do T6 5-40, I sit around 30-40 idle when warm. I'm running Mobil 1 5-30 for winter and it sits around 20 at idle.

And as for a quick lube places. Make sure they put the right amount of oil in. Those places put 5qts in anything that moves. And they put cheap white filters.

 

Are you running Mobil 5w-30 synthetic? I'm just running Mobil Super 5000 5w-30, with a Purolator classic filter. Normally I run Fram extended guard, but I had just had the head off so I wanted a cheap filter to catch any dirt I got in the engine.

 

Yes. I run only synthetic in my jeep. Either Mobil or T6 with a Napa gold oversized filter.

And that Purolator is better than that fram extra guard. Go Napa gold and don't look back.

 

Stop worrying,your pressure is fine. I will trade places with you b/c mine sits at 3 to 4 psi but it has been that way for over 50 thousand miles!!

 

More importantly it looks like you're starting to run a little warm.

 

Ok boy can't believe I missed that. OP you have some splaning to do