arsxj

Im going to get my oil changed in the morning and I neeed to know what I sould put in it. I took it to a quick lube before and im sure they put bulk 5w in it and 2K later I have engine noise and my oil pressure guage isnt reading it. I was told I should put 20W-50 in it. Does this sound right or is that too thick? Also whats the best brand for the 4.0L.

BTW its a 93 4.0 with 140K in FLORIDA so its not cold weathered

Abovetimberline

It is fine for fla,I would not use it in cold temps.

arsxj

Thanks. I just didnt want to go too thick. Im tired of hearing all the engine noise and the cheap oil has to be causing it.

djb383

Don't know about a '93 XJ, but 20W50 is a long way from what Chrysler says to use in a '98. The XJ is a fairly modern, water cooled engine, not an old school air cooled Harley engine.

http://www.supramania.com/aehaas/

STUK SUX

5w 30 or 10w 30. hell i only run 15w 40 in my diesel truck. who told you to use that heavy of an oil?

arsxj

Im in fla so it should be ok. Hell it was 85* here last week. It had 5 30 in it and after 1k it was so thin I started getting engine noise. I put 20w-50 High Mileage in and all the noise is gone now.

iateeple

Just a reminder:
At 85 degrees that "5" does not matter, the "winter" weight of the oil (in this case 5) begins at ~ 80 degrees..... I run Rotella T T6 5W-40 full synthetic in mine, works very well here in the winter(South Carolina,only about 25 at the coldest) . Just remeber,that 20W-50 is going to be too thick to lubricate the engine effectively at anything under about 60 degrees until fully warmed...some run it with no problem, BUT, and I should mention here that I am NOT an engineer, but after ALOT of studying, this is a very misunderstood concept, in a perfect world the oil will be as THIN as possible while still being able to build pressure in the cold,while being as thick as possible to maintain lubricity and therefore protection once warm. 5W-30 or 5w-40 is a very good choice....unless you have a VERY worn set of bearings( I mean way bad) 10W-40 is as thick as I would go. Alot of what the factory reccomends is for emmisions and fuel economy. Try changing it yourself if you can, and see if it uses any,if it makes any noises,etc., and just experiment.Best of luck!!

djb383

Did you read Motor Oil 101? What does 85 degrees and livin' in Florida have to do with using the proper weight motor oil when normal operating temp is +/-200F.........whether it's summer in Florida or winter in Canada. I'd be more inclined to believe Dr. Haas (author of Motor Oil 101) than some goober that perpetuates oil myths on the Internet.

TrekkerJmm

Hmm I have been using straight 30w for over a year in cold and hot temps and I run 60psi all the time, cold or hot in my 94 with 218,800 miles...Tj

jeepjerry

20w50 is fine, i run 20w50 in my cj-5 year round here in wisconsin. I run 15w40 in the 89 xj in the summer. Its only a band-aid for your engine though, there is something wrong internally if the oil pressure is down. It could last a month or it could last the rest of its life. With a 4.0, likely the later choice.

jeepjerry

well, the 4.0 strait 6 design hasnt really changed since AMC built it in the 60's, so it really is old technology.

zjrog

I killed a starter in a car years ago when I didn't switch from 20W-50 back to 10W-40 for winter. It got cold early that year and stayed cold. Once I got the little car running it wasn't too bad, but the starter couldn't spin that thick oil... Push started it for two days till I could afford to buy a starter!

djb383

I guess advise is worth what you pay for it. Is 20W50 ok?.........NO, not according to Chrysler/Jeep. Will it work.........according to some.....yes. But hey, ain't freedom of choice great.

poppajeep

I've used 20-50 in my XJ for the almost six years I've owned it. I bought it with 141,000 and now has 207,000 miles. When I change the oil, I use a quart of Lucas Oil additive, and four quarts of 20-50. The oil pressure looks fine, and it doesn't appear to use a great amount. It cranks a little slow on really cold mornings (Oregon), but unnoticable other times. The earlier post about it being old technology is true, as the mechanical parts started out in Ramblers in the '60's, although the peripherals are newer, such as injection, ignition, etc.

troy fritz

In the factory manuel it calls for 10w-30 is preferred.