New to XJ's - Problems

I just bought a 2000 Cherokee Sport 4.0L 2WD Automatic 64,000 miles. When test driving it everything was perfectly fine, however after a couple of days I started finding a lot of small things, well hopefully small.

Check gauges light came on and I noticed I had no oil pressure at idle when the jeep was warmed up. Took it to a good friend of mine that is a great mechanic and he said fram filters were crap and changing it may help, so thats what I did and it helped a little, but not completely. Just took longer for it to drop to 0. I took it back and they checked it with a mechanical pressure gauge and said it was an accurate reading, so they replaced the oil pump with a high volume oil pump, cleaned the pickup screen (which was already very clean), and the pickup tube. They said the pan was very clean and there was no sludge, etc. This kept the oil pressure from dropping to zero, but it still goes down to about 10psi at idle when it is hot. They tell me there is probably an internal problem, but I shouldnt worry too much as long as its running smooth and it is. Even when it was at zero before, it would run smooth.

Another problem that came after this. Check gauges light came on again, but this time it was b/c it was running hot (in the red). This ended up being a relay causing the fan not to come on and now that problem seems to be fixed.

I have read a lot and it seems these engines run very hot. Mine is now running around 210 - 220 at the hottest, but I can barely open the hood when ive been driving it. I think I will change to an electric fan and add a tranny cooler and maybe even a better water pump.

I also hear a slight knocking, which I have also read about. I hear it sometimes at idle and when going very slow, but when I speed up it seems to dissapear. Not sure if my mechanic friend heard it when they had it, but he says my engine sounds normal and the 4.0 is pretty noisy anyway. I would like for this to go away and I think I will try to change the plugs and wires next.

Minor problems that I will fix soon. The window lock switch is stuck on, I guess I will just bypass it. (how do you get the switch panel off, i try to pry it, but it feels like i am going to break something)

I love this vehicle and I want to fix everything on it. Any help will be greatly appreciated.

The best advice I can give you is to get rid of this Jeep or be prepared for it to leave you stranded and be prepared to dump major bucks into it.
The 4.0 is generally a very reliable engine but yours sounds like its trashed. Just how long has it run without oil pressure? More than a few minutes is too long if you ask me. Even after a new pump, it still doesnt hold good pressure. 210 is pretty normal temp for a 4.0 but it still sounds to me like its life has been cut way short by the lack of lube.

I have no idea how long it ran with no oil pressure before I bought it, but it didn't for long when I found it. I noticed it while stopped at a light and I gave it some gas and it raised up. I carried it straight to the mechanic. I have put some money into it now with the oil pump, brakes, tires, new stereo and replaced factory speakers, added receiver hitch and about to replace spark plugs. I still have my 98 f150, but I have money and a small loan wrapped up in the XJ so selling it probably isn't going to happen. If I have to have the engine overhalled I guess I will do it, but I don't want to have to.

Can't wait to hear some other responses. Hopefully some that sound a little better, lol.

Thanks

On the 2000, there are known gage problems.
Start with a new oil pressure sender (expensive...mine cost $56) and then check the instrument harness, the connector is a problem as well as the harness.

Search for this and your other problems in this forum.

well, the mechanic checked the pressure with a mechanical gauge and said it was running even with my stock gauge.

Yeah...but the sender is susceptible to oil leakage. That causes it to drop to zero and come backup. You can prove that by disconnecting the connector and cleaning the contacts. I use a piece of paper towel and some brakleen.

Finally, I got tired of doing that and bought a new one.

hmmmm... ill try that one out

i was thinking of getting a new mechanical gauge to mount inside. is there a way to keep both hooked up or should i just not worry about having both hooked up and just ignore the stock one?

Well, since yours is a newer model, parts are easy to come by. Just a matter or paying for it.

well i replaced the sending unit and the pressure actually reads slightly higher than it did before. now it gets no lower than about 11-13. also replaced the thermostat which was either staying stuck closed or wide open and causing it to overheat. new spark plugs installed and new battery. now i need to get a tranny flush/service and new window motor and i believe i will be adding electric fans and a tranny cooler. after that if i have to add anything anytime soon, i dont know what i will do. i am tired of spending money on this thing, but i love it.

Good work on the oil pressure sender, I cleaned for years and got tired of doing so.

I did a t-stat also and it cool a little better.

The external trans fluid cooler is a must. Had mine on since it was new. You can do the tranny flush from here since you will cut the return line.

You can skip the electric fan, but do replace the fan clutch if you think it needs it. Also check the condition of the serp belt.

A brake inspection should be next.

oh did i forget to mention that i added new brake pads? well they work great, but the rotors are still glazed and it still squeals till it warms up. i am hoping that just driving and using the brakes will slowly get rid of it.

I would replace the rotors. They are not that expensive. 100 bucks for two. Don't bother turning them unless low on cash.