Cherokee Fans,

99 XJ 167,000

Cold morning. Did not have time to warm up the Jeep as I do before every drive. Fifteen minutes into the drive I noticed lower than average oil pressure, about 25psi. Strange, since normally if pressure is not 40psi it is a few clicks higher. At a stop sign the pressure dropped to nothing, and the "Check Gauges" light went on. As I throttled on leaving the stop sign the pressure went back up and the light disappeared, but would go no further than 30psi. Before leaving work I warmed the engine, then checked my oil. Down a quart or so, so I immediately topped off and headed home. The trip home was the same as the trip out.

She seems to be running well. No unusual noises or dripping fluids. Please tell me this is a minor problem.

 

Could be a bad oil pump, but I would go buy a mechanical gauge, hook it up, and take it for a drive. Just to be sure before you go tearing stuff apart.

 

^^ x2

 

A mechanical oil pressure gauge can be rented from many big box parts stores. Call around. Temporarily install it where your oil pressure sending unit resides. Compare your readings to what you are seeing on the dash gauge.

Good data = Good decisions and oil pressure needs to be confirmed.

Below are the specs. for oil pressure for the 4.0

*Not less than 13 psi at HOT idle
*Between 37-75 psi over 1600 rpms

 

Is that the same pressure for Renix 4.0's?

 

yes

 

Any updates on this?
I just had the same thing happen to my 99...

Haven't driven it in a week or so, but it usually sat right at 40-50 PSI when driving.
Well I was driving to a buddys house just a few miles away and at a stop light I saw the check guage light come on, and notice the oil pressure at 0.. hit the gas and it went up to 20ish.. the last mile or so there it stayed right around 25..
I'm going to change the oil and filter first to see if that can help at all, but not till friday when its above 20 degrees...

What could be the problem other then the oil pump?

Also the oil level is exactly at the top of the safe mark.

 

Spun bearing.

 

Having the same problem. Changed the oil pump but after driving for a while it does the same thing