Oil for Jeep 4.0L

Messages
34,037
Location
Southern NJ
What oil would you guys run in the Jeep with the 4.0L? I'm looking into possibly buying one (among other cars [Big Grin] ). This engine seems to do well with thicker wt oils. I was thinking Amsoil S2k, 10w-40, or M1 15w-50 + 5w-30 Mix.
 
Messages
6,222
Location
KY
The owners manual for my 1999 Sahara specifies 10W-30 as the "Preferred" viscosity. As a result, I switched it over to M1 10W-30 soon after I bought it. I change the oil and filter at 6000 mile intervals and at 62000 miles it has yet to use a drop of oil. I seriously doubt that you'll see any benefits from switching to a higher viscosity.
 
Messages
342
Location
Limon, Co
When i was Wheeling my 2001 Cherokee. 5w-30 was prefered. these motors are pretty loose i think you could run **** near anything you wanted according to outside temps...
 
Messages
4,841
Location
Lakeville, MN
Owners manuals will suggest 10w30 as the preferred viscosity, with 5w30 suggested below zero. That's for later models with the 4.0. My '88 Cherokee with the 4.0 owners manual is much less restrictive: anywhere from 5w20 [freaknout] to 20w50, depending on temps. At 0 degrees and above, the suggested weights are 10w30 and 10w40. 20w50 was allowed if temps were going to be above 32 or 50 F, can't remember which. In any event, 10w30 will keep the motor running a long time, but the xw40's seem to be showing much better wear out of these motors.
 
Messages
3,216
Location
BC, Canada
Hey Gopher, I thought you liked 5W20. Any thought of trying it in your Jeep? I see its cooled off a little in your part of the country in the last few days. Don't leave the fire wood 'till the last minute.
 
Messages
4,841
Location
Lakeville, MN
I DO like 5w20, but as my owners manual calls for, 5w20 is to be used only if the ouside air temp does not rise ABOVE 0 F. Even in my colder than most part of the world, it isn't that cold all the time in the winter! I'm much more comfortable with the 5w30 under 60 F recommendation, and it seems to work well in the winter! For this engine, I can't imagine putting a 5w20 in there - just too old of an engine design for that to work well, IMHO. Wasn't cool yesterday or today. 97 yesterday, and 90 ish today with a boatload of humidity. Supposed to be back to lows in the mid forties over labor day weekend - back to good sleeping weather!
 
Messages
5,069
Location
Saratoga, NY
buster, did you try a search on "Jeep" or "Cherokee," etc ...? Some really good results using the better 15W40s, if my memory is correct. --- Bror Jace
 

buster

Thread starter
Messages
34,037
Location
Southern NJ
I think I'm going to run S2k in all my cars. I want to try this oil again. I think in a Jeep it would be a good year round oil. Its a decent 30wt that should be good for the 4.0L.
 
Messages
5,785
Location
Dixie
Buster, I have several local customers with Jeeps and the V-6 engine....The Amsoil 0w-30 works very well in this application and provides a measureable increase in fuel efficiency - typically 1-2 mpg. I'd highly recommend it in this specific case .... Tooslick
 

buster

Thread starter
Messages
34,037
Location
Southern NJ
Thanks TS. [Cheers!] FWIW, my friend is going to be running S2k in his Vette. A local mechanic who does high end work recommends. Better oil pressure and engine temps.
 
Messages
4,841
Location
Lakeville, MN
quote:
Originally posted by TooSlick: Buster, I have several local customers with Jeeps and the V-6 engine Tooslick
Must be the '84-86 Cherokee with the dreaded GM 2.8l V6 or the new Liberty... About the only Jeeps with a V6 that I can remember off the top of my head! Everything else gets an inline 6 or a V8! Just pokin fun at ya! [Cheers!] I appreciate the Amsoil info you contribute. [ August 29, 2003, 01:51 AM: Message edited by: MNgopher ]
 
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