I've recently experienced the dreaded 0 oil pressure gauge with my "check light" appearing at idle. Lower pressure (1/4 - 1\2 at higher rpm). Engine feels fine, oils up and I suspect a bad sensor. Since it's Xmas all stores closed.

I have taken off the harness pigtail, and will test the pressure with a kit from autozone tomorrow and try a replacement sender unit.

My question is: I noticed oil between the harness and sender unit itself. Is that a sign of a failed sensor by itself?

Also anyone know what size and depth of a socket I need for that? My extreme kobalts aren't gonna work here.

99 XJ 4.0 STRAIGHT 6

 

Channel locks to remove, and oil theres deff not good.

 

indeed I used channelocks with no problem

 

Well, I had used some wd40 and cleaned the oil from the pigtail on the harness as well as the back of the switch.

I used a ziptie to see if anything was in there. For giggles I put it all back together and drove her for half an hour. No problems. I suspect the oil I seen between the pigtail and switch was old, as it was pure black and I've since changed the oils to synthetic and it's pretty clean (still).

This makes me wonder if it wasn't from another time or else.

I will keep an eye out to see if oil still seeps out into the harness or the threadpoint itself.

 

Great job.

 

My gauge is doing some funny stuff too...
One day it is normal (moving around with revs) between 15 and 40 and then it says Zero or all the way up to peg out at 80.
Sensor? where is it...

 

SENDER. Right above the oil filter.

 

A 27mm deep well will work on later model "stubby" 3 wire sensors. My 2001 has this type.

An"oil pressure sensor socket" from Auto Zone will work on earlier models. It is a long sensor and requires an extra long socket such as the special tool from Auto Zone. It's 1-1/16" iirc.

I use a stubby ratchet on both.