I will be changing my oil soon and want to use up some Amsoil oil. The Jeep normally runs on 10W30 but can also take 5W30. I will use 5QTs of ASL (5W30) and 1 QT of Amsoil 15W40. Not that I want to mix weights or anything, just thats what I got.
oil for 2001 Jeep GC 4.0
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Yep, Jeep 4.0s like a 40wt oil. They run a little quieter with it too. I ran Rotella 5W40 in mine for 10s of thousands of miles. I switched to M1 HM 10W40 at the last oil change and will stick with that for the time being.
I have an'02 wrangler w/4.0,133k miles.It lives on 0w20 in the winter+5w20 in the summer.Holds 30-40 psi oil pressure at idle in the summer.It doesn't use any oil in 5k oil changes.It is no louder with these than back when it ran on 5w30.Kurt
cowtipper- why do you run such a low viscosity oil in your 4.0??? Those engines like, no really like a thicker viscosity oil between their moving parts. 10w-30 is Factory Recommended for a reason. They dont recommend 5w-30 for the 4.0 inline 6 at any time, anywhere. Amsoil does in cpld climates(below32), but 10w-30 in all other temps.
Originally Posted By: 84zmyfavorite
cowtipper- why do you run such a low viscosity oil in your 4.0??? Those engines like, no really like a thicker viscosity oil between their moving parts. 10w-30 is Factory Recommended for a reason. They dont recommend 5w-30 for the 4.0 inline 6 at any time, anywhere. Amsoil does in cpld climates(below32), but 10w-30 in all other temps.
Wrong...my 2001 owners manual allows 5W-30 for temps below 60 degrees.
cowtipper- why do you run such a low viscosity oil in your 4.0??? Those engines like, no really like a thicker viscosity oil between their moving parts. 10w-30 is Factory Recommended for a reason. They dont recommend 5w-30 for the 4.0 inline 6 at any time, anywhere. Amsoil does in cpld climates(below32), but 10w-30 in all other temps.
Wrong...my 2001 owners manual allows 5W-30 for temps below 60 degrees.
Not sure why a 5w30 would not be fine. Even year round. A 10w30 and 5w30 are both 30 weights with just different winter flow ratings.
Originally Posted By: Slick17601
Originally Posted By: 84zmyfavorite
cowtipper- why do you run such a low viscosity oil in your 4.0??? Those engines like, no really like a thicker viscosity oil between their moving parts. 10w-30 is Factory Recommended for a reason. They dont recommend 5w-30 for the 4.0 inline 6 at any time, anywhere. Amsoil does in cpld climates(below32), but 10w-30 in all other temps.
Wrong...my 2001 owners manual allows 5W-30 for temps below 60 degrees.
Have to agree....my 00 and 04's both spec 10w30 above freezing, and 5w30 below 60F. Using 0w30 in the winter now.
Originally Posted By: 84zmyfavorite
cowtipper- why do you run such a low viscosity oil in your 4.0??? Those engines like, no really like a thicker viscosity oil between their moving parts. 10w-30 is Factory Recommended for a reason. They dont recommend 5w-30 for the 4.0 inline 6 at any time, anywhere. Amsoil does in cpld climates(below32), but 10w-30 in all other temps.
Wrong...my 2001 owners manual allows 5W-30 for temps below 60 degrees.
Have to agree....my 00 and 04's both spec 10w30 above freezing, and 5w30 below 60F. Using 0w30 in the winter now.
Yep, Im bad. I looked in my 01 XJs manual, and it does say its ok to use 5w-30 in temps 60 degrees F and lower.
I would not run a 40 viscosity oil in it. You probably not going to hurt it but, the 30 viscosity would be better for it just use a stout 30 in it and call it a day. VR1 would be a top 5 oil to use in the 4.0L for the flat tappets and its on the thick side of a 30. Thicker oils than needed make the engine run hotter than whats needed and work the oil pump harder as well. Just my two cents.
Originally Posted By: addyguy
Cheaper, easier to get option is a 10W-30 HDEO.
That's what I run in mine as well, Rotella T 10w30 is very good stuff. Lots of goodies in the add pack that are a plus for the old 4.0
Cheaper, easier to get option is a 10W-30 HDEO.
That's what I run in mine as well, Rotella T 10w30 is very good stuff. Lots of goodies in the add pack that are a plus for the old 4.0
I would never run a 20wt in a 4.0...your lifters, piston skirts and bearings probably hate you. I'd stick with at least a 30wt....and UOAs show the 4.0s prefer a thick 30wt or 40wt oil. I used to run 5W40 in mine for many years but have since changed oil brands and I now run 10W40 in it.
Who said anything about running a 20 weight oil in a 4.0? Jeez, I would hope you wouldnt do that. Im a firm believer that Jeeps(well, 2004 and older) like thicker oils, not only in their motors, but transfer cases and diffs also. Ive got 6 Cherokees, 4 of which drive regularly, and the thinest motor oil I use is in the lowest mileage one, a 2001 Cherokee with the 4.0 Inline 6, and she gets 10w-30 in the winter, 10w-40 in the summer. Quaker State both times.
Originally Posted By: VR1
I would not run a 40 viscosity oil in it. You probably not going to hurt it but, the 30 viscosity would be better for it just use a stout 30 in it and call it a day. VR1 would be a top 5 oil to use in the 4.0L for the flat tappets and its on the thick side of a 30. Thicker oils than needed make the engine run hotter than whats needed and work the oil pump harder as well. Just my two cents.
How would a thicker oil make the engine run hotter?
I would not run a 40 viscosity oil in it. You probably not going to hurt it but, the 30 viscosity would be better for it just use a stout 30 in it and call it a day. VR1 would be a top 5 oil to use in the 4.0L for the flat tappets and its on the thick side of a 30. Thicker oils than needed make the engine run hotter than whats needed and work the oil pump harder as well. Just my two cents.
How would a thicker oil make the engine run hotter?
Supposedly thicker oil travels back to the sump slower if not hot enough, therefore displacing less heat.
I run thicker than factory recommended weights in my Jeeps, and I think they last because of it. Ive had many Jeeps, Cherokees in particular, and I just think, no...feel that they want thicker oil coursing through their Cast Iron Veins.
My sig says it for me.
My next test fill in a Jeep 4.0 will be M1 0w40. I've been running T6 5w40 and love it, but I don't see any down-side to M1 0w40- its got virtually as much zn/p.
OK, the downside is availability... many places carry T6 and M1 TDT but not 0w40.
OK, the downside is availability... many places carry T6 and M1 TDT but not 0w40.
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