tigerpilot@bellsouth.net

I have recently squandered many hours trying to understand an oil pressure problem in my 2004 4.0 liter. I purchased it 4 years ago at 60K miles. It now has 120K miles. I have religiously changed the oil, and been impressed with the oil pressure gauge staying rigidly at just over center, even at hot idle, until just now. I have been a part time mechanic all my life, and was amazed that the pressure never seemed to deviate due to the normal wear on the bearings. Just recently it started to drop to 0 at hot idle. It turns out that Chrysler/Jeep wanted to keep the standard panel, with a gauge, for all of the engine options. On the 4 liter six, in order to save a few dollars, they put an idiot light sender (single wire switch) on it, and rigged the Body Control module to move the gauge to the center position if you had any oil pressure at all. What deceit. How cheap *** can any company be? shame on those who made that decision. Never never will I buy another one. Never.

dave1123

You should try a sender specifically designed for a 2000. I had to replace the sender in my 2000 WJ and got one from NAPA. All it did was show me 40 psi all the time! I went to the dealer and got one specifically for my 2000 and it works like it's supposed to do.

Ralph77

From an '00 4.0 XJ point of view but did you buy the better Echlin one or the cheaper MPE one?
My original, guessing on that, started reading 80 all the time.
Swapped it out with the Napa Echlin one and it has been good for about 5 years now.
Finally got around to checking my oil pressure with a mechanical gauge last year.
Plumbed in some fittings so I could run both at the same time.
The mechanical gauge and the cluster pretty much read the same.
All that being said would not be the first time a part was bad out of the box. LOL.

dave1123

Back when many cars just had idiot lights, many people installed aux oil pressure and temperature gauges in the dash or on a panel under it. When we were young, that was the first thing we did with our cars. Summit Racing still sells them. The oil pressure gauges were mostly mechanical requiring a nylon tube to be installed into the cabin, hoping they don't blow off!