I too have a 2000 Cherokee Sport 4X4 and I too have an oil pressure problem as
Described in this thread. 36 psi indicated during cruise and often so low in idle the “Check Instrument” red alert shows. Oil change with regular winter weight had no affect. Any further developments of which manufacturer oil pressure sensor to use. Does anyone know how in actual fact the best way to check the actual oil pressure in the vehicle.
Regards, Steve

 

Any coolant loss?

what brand oil filter are you using?

 

Cruiser's questions are important, so don't ignore them. He's going somewhere with both of them. But I'll respond to this:

Yes. It's easy. Either buy an oil pressure test kit (manual oil pressure gauge) or borrow one from Auto Zone or a similar parts store tool loan program. Harbor Freight gets a bad rap sometimes, but I have this one, and it's actually pretty good for the money:

https://www.harborfreight.com/engine...kit-62621.html



Then you remove the oil pressure sending unit, screw the mechanical gauge in its place and read the oil pressure right off the mechanical gauge.

If the mechanical gauge reads good oil pressure, it's very likely the sending unit.

If the mechanical gauge reads low oil pressure, you have another issue going on and will need to investigate further.

 

Cruiser and Extrashaky (love that one)
Thanks much gents great advice.
No fluid loss
Engine oil uncontaminated.
Harbor freight kit ordered.....regards, Steve

 

I want to check my oil pressure as well......just to make sure my dash gauge is correct.

The tester doesn't have to be specifically for oil, does it? I have a compression test kit, similar to the one pictured above.

 

A compression tester is going to have a check valve in it to hold the highest pressure it sees during the stroke. That might not give you an accurate reading when checking oil, especially if you're trying to see what the pressure does at different RPM. The compression tester is also probably going to have a higher range and may not even show you the low end. It may be hard to read.

Otherwise I don't see why not. Personally I wouldn't mix them because that check valve may not be designed for oil to run through it, but I'm probably just overly cautious. The HF kit is cheap ($5 cheaper if you use a 20% off coupon), and borrowing one from Auto Zone is free.

 

Gotcha......that makes sense. Guess I'll add another piece to the tool box.

 

I bought the HF one myself recently since none of my local Autozone/Advance/Napa stores had it available as a loaner tool.

I figured that for less than $20 it was worth buying since I doubt it'll see a ton of use. It worked perfectly for me and confirmed that my oil pressure was reading correctly on the dash gauge and was running high.

My problem turned out to be that I had a Fram oil filter, which I didn't realize was a big no-no, so I put a WIX filter on the Jeep and since then my oil pressure is right where it should be.

 

Really? I've never heard that about Fram. I've been using Fram for over 30 years and never had any issues

I know it "should" be, but isn't the pressure sending unit reading the DOWNSTREAM side of the filter???

 

As far as brands for the Oil Pressure Sending Unit, obviously a Mopar one is best, but I did a gauge swap recently and used BWD (Both Advance and Pep Boys carry this brand) and it has worked well for me so far.

 

I have no idea if it's downstream or not.

I had read that in recent years the quality of Fram has gone downhill and the ports may be too small. Reading the recommendations for high quality filter brands, WIX was both on the list and for whatever reason listed as good if you idle a lot (which I do) and they happened to carry it at the local auto parts store. I'm sure that the recent arctic temperatures had a hand in pushing the pressure up as well, but the next step in troubleshooting high oil pressure was to look at the oil filter, so that's what I did.

I couldn't believe the difference in how my engine ran between the 2 filters. I did NOTHING else, literally just removed the Fram, installed the WIX and replaced the oil that drained out when the old filter came off. My Jeep runs discernably smoother and quieter with the WIX than it did with the Fram.

 

That's good to know. Trying something different isn't gonna cost me anything, so I'll give it a shot. Thanks for the info' Pat.

 

Anytime. Of course, my problem was pressure running too high rather than too low, but the typical troubleshooting steps are pretty much the same.
1 - Test pressure with mechanical gauge to determine if sending unit is correct. If different, replace sending unit.
2 - Check that you're using a high quality filter that is recommended for the Jeep I6. WIX(Napa gold is rebranded WIX), K&N, Mobil 1 are among the top rated filters. Many people will tell you to avoid Fram like the plague.
3 - Check oil filter mount passages and sending unit passages for any blockages.