Radi

The oil stabilizer has one useful purpose- to quiet down an engine long enough to dump it on someone, if you are inclined to do that sort of thing. Shady used car dealers love the stuff.
Would you add a quart of 90-wt with no detergent or additive pack without even a SA rating to your crankcase?
I've never understood what about modern motor oil needs "stabilizing".

Potatowalker

I used to always use Valvoline durablend 10w30. It did well in all but the very coldest weather (below -10F). I recently started using 10w30 full synthetic sold/labeled by Car Quest because the guys in there tell me it's made by Valvoline and is identical but cheaper. I've also used Valvoline full synthetic for a bit and honestly the only difference I've noticed is how much better full synthetics are for really cold starts. It started WAY easier with 5w30 synthetic at -40F a couple of times last winter. I now plan on using the C.Quest 5w30 full synthetic in the winter and 10w30 in the warmer weather. The C.Quest premium filters are made by Wix so I've always used those and been happy too.

I tried the Lucas stabilizer stuff on my old jeep when it turned 200K to see if it would quiet things down any. It didn't make any noticeable difference and almost seemed like the oil started to break down way earlier than usual. I won't be using any of their stuff again.

A little off topic, but I've found the synthetic gear oil and transmission fluid to be a lot better for cold weather as well. It made a noticeable difference for the better when I switched them all to synthetics. Way less resistance when the fluids are cold since they are more viscous and warm up a lot faster than dino oils.

scubadvr

I've been using Mobil 1 for 60k miles with no problems.

89cherokee2gtmudy

I use Castrol GTX 10-30 conventional and a STP or Purolator in my cherokee and comanche. When I first got my comanche running I used Walmart super tech for the first few hundred miles. Since then castrol with no problems. Never ever use a fram oil filter on anything. I've had the night mare of one crushing while attempting to remove it on my comanche when I bought it. Plus every low mileage motor I find bad at the junk yard has a fram on it.

salad

You noticed that too, eh? BTW your low end STP units are the same build as the low end FRAMs.

89cherokee2gtmudy

Purolator's are my first choice. Only time I use a STP is if I can not find one in stock around town. Only 3 stores carry the size for the 4.0 and that size seems to run out. Odd cause theres not that many 4.0 jeeps around my town.

123456bmx

Rotella-t 15w-40 and a wix filter

I havent used it in the winter yet because I just switched,but it doesnt't get below 10*f in my parts so Im probbably gonna run it year round

SamC130

I only use AMSOIL. Been using it since it first came out in the 70s. Best oil there is.

hankthetank

LOL^^^^

Cherryokee

Valvoline MaxLife 30W and a cup of MM - since new. Now 183K miles, still running clean and strong.

cruiser54

All I've used for years.



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

dmill89

It's good oil but expensive as hell and kind of overkill for the AMC/JEEP 4.0L I6.

The 4.0L I6 isn't exactly picky when it comes to oil. Just about anything that says "Motor Oil" on the bottle will work (and in a pinch you can run ATF as oil in it to get you some ware that you can get some "real" oil) and Rotella T5/T6 has been shown to be excellent for the 4.0L I6 at less than half the price of AMSOIL.

Jeepster242

I run 10W-30, (Mobil One usually), but many other major brands will work just as well. I would wait (at the max) 7500 miles between changes. But, just like you, i'm willing to spend a little more to make it last longer, so i change mine every 5000, i also pour in some seafoam with each change to help keep the motor clean.

xjsnake

Me Too...

cruiser54

Yup. In all 3 of my Jeeps, riding lawnmower, rototiller.