They go together like peas and carrots.

 

Reason I'm curious is the T5 is the only one I can find around here in 10w and the T3 which is the one I originally wanted to use, only comes as 15w which is to high since we do get in the teens here in Oregon.

 

We get i the single digits here also. Don't sweat it.
Wanna see the factory recommended oil weights for the early years of the 4.0?



Jeep Engine Oil Viscosity

This was taken from pages 82 and 83 of the 1989 Chrysler/Jeep owners manual.

Selecting Engine Oil Viscosity

When changing or adding engine oil select the proper grade by using the chart on the following page. Select the grade that corresponds to the ambient temperature range you expect to encounter before your next oil change.

30*F to 100*F+ 20W-40 or 20W-50
0*F to 100*F+ 10W-30 or 10W-40
-20*F to 60*F 5W-30

 

T3: Pure dino juice 15w40 and 10w30
T5: Sometimes a synthetic blend (5w30), sometimes a pure syn (0w40)
T6: Full synthetic 5w40

Anywhere it gets cold it's a good idea to run an oil with lighter startup viscosity and better flow like a 0w or 5w. 30 and 40 multigrades are fine. These oils can be run all year or you can do something heavier in the warm seasons to save costs, like 15w40.

The 4.0L really really likes heavy duty diesel oils. One reason is that gasoline oils have changed so much since the 4.0L was designed, particularly with API SN. Rotella and its ilk provide additive levels the 4.0L expects. In fact, if you're concerned about longevity, the best Used Oil Analyses in our engines consistently are Shell Rotella T6 and Mobil Delvac 1 ESP. Both are synthetic 5w40s with a quality additive package.

I am a Rotella fan boy but you can also go with Chevron Delo 400, Mobil Delvac, or Valvoline Premium Blue.

And do not forget to run a good filter! WIX 51515 is a good unit. A more rugged option is 51452. I am running 51459 and am very impressed with the cold weather performance, though I don't think it'll fit on years with vertical filters.

 

I have an 87 anyone know what larger filter will fit?

 

Wix 51515

 

Purolater 30001

 

Motorcraft FL1A

 

WIX 51459 on model years with horizontal adapters



If not, WIX 51452 is an upgraded version of the 51515 that holds up to abuse offroad.

Baldwin B2-HPG is a good choice as well.

 

So what's the difference in the 59 and the 52?

 

51459 is massiver. 51452 is the same size as 51515, FL1A, PL30001, and so on. It's used on a lot of tractors, loaders, boom lifts, etc. Mostly Perkins diesels (some Caterpillar applications but those are really Perkins units post-acquisition)

 

On a related note, I changed my oil last week, I want to beat the engineer over the head that decided to put the oil pressure sender in that location.
I hate having to finagle the filter around that thing.

 

And no I'm not unplugging it, you don't know my luck, I'll just break it.

 

So 51515>51542>51549?

 

Backwards, 51459>51452>51515. Apparently 51459 won't fit on model years with vertical oil filter adapters.