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What oil I need to use? SAE 10W-30?

R

rpaniza

NAXJA Forum User
Location
Panama
My car is jeep cherokee 99 4.0L 6 Cil. It has 99,000 miles. I have always changed it very frequently, but I have been using the SAE 10W-30. Continuous with the same or change the specifications of the oil?

Thanks
 
With as hot as it gets down there I would think a little thicker oil might be better. I run Castrol GTX 20-50 in my '99 with a little more than 120,000 miles on it year round here in Texas.
By the way.....
WELCOME to the board! :)
 
drifto77 said:
With as hot as it gets down there I would think a little thicker oil might be better. I run Castrol GTX 20-50 in my '99 with a little more than 120,000 miles on it year round here in Texas.
By the way.....
WELCOME to the board! :)
Click to expand...

OK, my geography might be a tad off, but IIRC it is more humid in Panama then anything. 10-30 should be fine.
 
What does your owners manual say ? I know that in 99 or 00 the recommended oil was changed from 10w30 to 5w30 at some point. My wifes 97 olds takes 5w while my 98XJ takes 10w as the recommended. I run 10W30 Mobil-1 all year in mine and 5W30 Mobil-1 in the wifes. The kids TJ's both run 10W30...
 
According to a Mobil OEM sales rep, 10w-30 (green) and 5w-30 (blue) are the same, only marketed in different bottles.
 
I'm not too technical about oil but I've seen/done a lot in +30 years and 10W/30W seems thin for a HOT, broken-in 4.0. I think the later years were dealing with CAFE standards and might have cut it pretty close qualifying 10W/30W? If this were my engine operated in that climate I'd probably run a decent 10W/40W viscosity.
 
Go to www.bobistheoilguy.com and search the Used Oil Analysis forum for 4.0 Jeep. You will find the wear numbers (metal in the oil worn from the engine's parts) are typically lower for 40 weights. You can find my UOA's on there under the same username, and my results will confirm this as well.
 
Sparkman said:
Go to www.bobistheoilguy.com and search the Used Oil Analysis forum for 4.0 Jeep. You will find the wear numbers (metal in the oil worn from the engine's parts) are typically lower for 40 weights. You can find my UOA's on there under the same username, and my results will confirm this as well.
Click to expand...
OK, next question: where do you get your oil analyzed at?
 
My car is jeep cherokee 99 4.0L 6 Cil. It has 99,000 miles. I have always changed it very frequently, but I have been using the SAE 10W-30. Continuous with the same or change the specifications of the oil?

So youre in Panama... Actually I am kind of surprised that you can even find 10w30 easily there being as its hot. From my experience in Mexico, straight 40 is common along with 15-40, 20-50 and 25-50! The lightest I've ever seen there is 30 (straight). I agree that reccomendations of 5-30 are a result of the CAFE fuel economy standards and it doesn't seem right on a 4.0, a motor that has rather loose clearances anyway and thats not to mention if its high mileage. What you were using is probably not a bad choice given the motor was "just broken in" Personally I like to use diesel lube in my 4.0 as some other jeep owners have reccommended since it keeps the lifters from gumming up and the pistonslap quiter with all that phosphorus they put in it but thats another topic anyway. So what youre using is probably fine but I'd warn that the cherokees tend to run hot.

Recently I bought a new dipstick from the GM dealer for a 350 thats used as a boat motor. On the dipstick it says "Use only 5w20" or something rediculous for a motor that sees constant 3500 rpm speed. Even an automotive 350 would probably want a little thicker oil right? Of course, do the car companies or the epa for that matter want your car to last 2x as long???
Click to expand...
 
XJXJ said:
I'm not too technical about oil but I've seen/done a lot in +30 years and 10W/30W seems thin for a HOT, broken-in 4.0. I think the later years were dealing with CAFE standards and might have cut it pretty close qualifying 10W/30W? If this were my engine operated in that climate I'd probably run a decent 10W/40W viscosity.
Click to expand...


I've changed my thinking on 10w-40 recently based on what I've read. "Experts" say there is too much spread in a 10-40 and too much vicosity index improvers much be used. Even though a 20-50 still have the same 30 spread, it's different because you're starting out with a 20 weight. I'd go with whatever weight the owners manual states but definately use syn.
 
XJXJ said:
I'm not too technical about oil but I've seen/done a lot in +30 years and 10W/30W seems thin for a HOT, broken-in 4.0. I think the later years were dealing with CAFE standards and might have cut it pretty close qualifying 10W/30W? If this were my engine operated in that climate I'd probably run a decent 10W/40W viscosity.
Click to expand...


I run 10w 40 in mine as well It has never let me down. I have run it in many other cars and Jeeps too. 10w40 is the way to go. JOE>
 
correct me if i'm wrong but i was told the 1st #is the weight the oil will flow at cold temperatures, 2nd # is the weight of the base oil. i.e. 10w40 = 40 weight oil and flows like 10 weight when cold?
 
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