[keith95jr]

im sure im not the first person to ask about this since i have seen diff. things about it but here it goes any ways. got in the jeep started it up and drove for about a half hour or so on the highway, once i came to a stop the oil pressure dropped to 0 and the light came on, while driving the pressure goes back up to normal and is not a problem unless i come to a stop again. if im stopped at a light and i keep the rpms around 1000 or so the pressure stays up. i went into the store and came out and im guessing since the oil had cooled down some the pressure stayed normal until it got back up to temp. i guess my question is, is this a fairly common problem? is it more the oil?, pressure sender? or the pump ? there is no knocking or anything like that and it drives normal other then maybe not having any pressure when sitting still lol. and yes it has oil

oh its a 99 wrangler, 4.0 and it has also about 180k.

any help would be great since its cold out and i dont feel like going out and swaping parts until i have a decent idea of what it is, so if this is a common problem knowing would be helpful. im leaning toward replacing the pressure sending unit, and seeing what happens since its only about $30

[flatlander757]

edit: forget everything I said... I'm getting oil and engine temp sending units/sensors mixed up.

Correction:

Yeah definitely try changing out the sending unit first as it's cheap and likely the problem. When the sending unit gets old it can lose some of it's "sensitivity" and cause lower than actual readings to the gauge and warning light. VERY common problem in older Chryslers as well as many other vehicles.

I know you're in MD, but I've got an oil pressure test gauge you could hook up if you trekked down to VB for a day.

[keith95jr]

the gauge is the needle and as far as i know its not a dummy gauge because it moves as the rpms move, and its just the check gauges light that comes on when the guage drops to 0 not the check engine light or low oil light.

[flatlander757]

Originally Posted by keith95jr

the gauge is the needle and as far as i know its not a dummy gauge because it moves as the rpms move, and its just the check gauges light that comes on when the guage drops to 0 not the check engine light or low oil light.

Yeah, reread my first post... was getting oil and coolant sensors mixed up. There's only one oil pressure sending unit which works the gauge and the light.

In a nutshell slap a sending unit in there and call it good.

[Jerry Bransford]

A bad oil pressure sender that causes the oil pressure to drop to zero and illuminate the Check Gauges light is common, it happened to my '97 TJ. There were a lot of them in early TJs, there must have been a bad batch of senders used in the early TJs. Replace the sender and it should be fine, mine has been fine for 10 years since I replaced it after it did the same thing (which nearly scared the crap out of me on a lonely desert road near midnight one night).

[MudBox]

the sending unit is the first place to look, but be careful when this was happening to my jeep it turned out that the previous owner had driven the piss out if the jeep and in 50k miles had caused the crankshaft bearings to go out and the motor had to be replaced.
thankfully it was under original waranty.

[never monday]

I'd have to put a mechanical gauge on it and see if the pressures are real. At 180k it's possible to have enough wear to cause this. I'm not trying to be an alarmist. Just trust the sending unit is bad but verify it with a mechanical gauge.

[keith95jr]

thanks guys, ill probly replace it in the next day or so ill pop in and let yas know what happens