Fluctuating oil pressure.

1997 Cherokee sport. I changed over to synthetic about 500 miles ago. Tonight while driving(cruising) the check gauges light lit up. Usually the oil pressure needle is at 50psi at 65mph. It started fluctuating from 20 tp 40 psi in slow to medium increments(in ping pong fashion). When I would come to a stop or slow down pressure would stay somwhat stable at 40psi. Are oil pressure sending units known to fail on the 4.0l? Where exactly is it located? I used a mobil 1 filter and valvoline synthetic, but doubt it has anything to do with it.

Yes, the senders are prone to fail. They are mounted on the oil filter adapter. On earlier XJs it is common for the sender wire to come loose during filter changes, so check the connection on yours.

For peace of mind rent an mechanical oil pressure gauge and test.

Thank you!

yea the senders can go out and do that, maybe check or replace

I have had best luck (by far and I've replaced many) with the oil pressure sending units from Jeep. Aftermarket stuff is very hit and miss.

birchlakeXJ said:

I have had best luck (by far and I've replaced many) with the oil pressure sending units from Jeep. Aftermarket stuff is very hit and miss.

Click to expand...

Are we dissing the manufacturing prowess of our third-world brethren?

check em for leaks too! when they crack, they give some funky readings and start with a slow drip, and end up DUMPING oil. ask me how i know... 3 quarts in 30 min of drivin sucks