I have 2000 XJ with 132K miles....Bought it 3 months ago and just put 1200 miles on it since I changed the oil when I bought it. Every once in awhile the oil light comes on briefly. Just took it on a 250 mile road trip a few weeks ago and light never came on. Are the Cherokees 4.0 cyl. known to burn oil? maybe a little low? is there a sensor that triggers oil light when a little low or could it be something else? I took it to my trusted oil change guys when I bought it........

 

Before I even read your post I suspected it to be a 2000-2001 4.0.
Do a google search or search this forum and you will see this to be a common problem. The worst scenario is a cracked head but that year also had some leaky head gaskets. Either of these issues will allow coolant to mix with the oil and wipe out the bearings and/or lifter bores which will result in low pressure. They also had a problem with cam bearings walking out of its bore.
I have a 2000 that has had 4psi for years and drives fine with no issue.
Are you losing coolant? If the answer is no your probably in the clear.
Low pressure at idle does not always mean the end is near. You just may have enough wear to drop the pressure. Multiple bearing/lifter bore wear is accumulative which reduces oil restriction but the tolerances can still be within spec.
The first thing to do if your concerned about it is to verify pressure with a test gauge.

 

how would I know if I was losing coolant? just by keeping eye on reservoir?

 

And if you are concerned about low oil level, I would suggest checking it often until you know your Jeep well enough to not be concerned.

Does the 2000 come with both a gauge and low oil level light?

 

just red oil light

 

One of the biggest favors you can do for yourself is track down a cluster with gauges and swap out with the idiot-light cluster.

4.0's are not necessarily known as oil burners.

 

dang thing runs great.....every once in awhile when I get done driving it and walk towards front of jeep it almost smells like it is running hot or burning oil smell....

 

They do have a couple of common leaks, oil filter adapter, valve cover....see anything there?

 

Swap full gauge cluster, and also rent/borrow/buy a mechanical oil pressure gauge and confirm pressure.

 

The engine bay gets pretty hot due to the limited space with that 4.0 shoehorned in there. And with a bit of oil leak, it tends to smell like burned oil quickly...

 

Anytime low oil pressure is suspected, it should be "verified".

Get a mechanical oil pressure oil gauge. They can be rented inexpensively at many parts stores; call around.

Temporarily install it where the current oil pressure sending unit resides (right above your oil filter). Then you'll know for sure.

The oil pressure spec. for the 4.0 engine is as follows:

*Not less than 13 psi at HOT idle

*Between 37-75 psi OVER 1600 rpms

And yes, keep an eagle eye on your coolant reservoir. Unexplained coolant loss is the #1 symptom of a cracked 0331 cylinder head. And if not caught quickly, that can wipe your bearings and result in low oil pressure on your engine.

 

And remember that if you only have the oil light (not the gauge): this is relating to oil pressure, NOT oil level...you can have great level with crap pressure..