Oil and Filter Suggestion

I just bought a 98 XJ a few weeks ago with 130k on the 4.0L. It has good oil pressure while driving, but after i reach normal operating temps, it falls to around 10psi at idle. I have read some posts regarding oil and filters, but wanted to get everyone's opinion. I drive about 250 miles per week (mostly highway) and plan on off-roading at least once a month. Thanks for your input.

What make filter? What brand of oil and its viscosity?

Have you verified the gauge's readings with a manual pressure gauge?

My 98 (150K) does the same thing, summer and winter. I run rotella 10w30 year round. I had a mechanic tell me that you only need to have 1.5 psi of oil pressure for every 100 RPM. So at 1000 RPM you'd be looking for 15 psi. When you step on the go pedal, does your oil pressure go up?

I'm thinking that I need to have a look at the inside of my oil pan. I think there's probably a good amount of sludge and grime on the bottom that could be cleaned. I also need to clean the oil pickup most likely. Maybe even a new oil pump.

If it's just started hapening, it could be a filter issue.

1. Verify oil pressure with a mechanical gauge if you're unsure of accuracy and yes, your oil gauge can be off.

2. SEARCH for tons of light reading on oil and filters. No need to reinvent the wheel here.......

3. Factory spec. for oil pressure for the Jeep 4.0 engine:

13psi MINIMUM at HOT idle
37-75psi on a hot engine running above 1600 rpm

Use a high quality filter,Wix.Mobil one,Puralator gold Napa gold.
Your engine with higher mileage may like an an oil with a higher vicosity like 15w40. I see your in the south so cold start is not a problem.

I'm doing an oil change soon and was curious as to what a good oil to use is. I've searched best oil and just oil and come up with nothing.

LazersGoPEWPEW said:

I'm doing an oil change soon and was curious as to what a good oil to use is. I've searched best oil and just oil and come up with nothing.

Click to expand...

that took me about a minute to find using a search

http://www.naxja.org/forum/showthread.php?t=943013&highlight=recommend+motor+oil

kf_chris said:

that took me about a minute to find using a search

http://www.naxja.org/forum/showthread.php?t=943013&highlight=recommend+motor+oil

Click to expand...

Thanks I was having trouble using the search. Especially with the 15 second wait in between searches.