I am not being a bad guy hear im.just trying to provide solid fact of many many years of reading and like I said taking the variables in
If you want proof take 0w20 any flavor of your choice
Now run it for the recommend 5-6 oic and send it to black stone labs, that my friend be proof and helped wear your motor out faster, only reason I say this is because people have been there and done that

 

The answer is elementary...which ever oil you want.

This issue is worse than a dead horse. Everyone has their own opinions and reasonings of oils so no matter which you choose some here will agree and others won't.

 

After 6 pages of oil confusion, I'm not sure you found your answer.
I bought a 2000 with 127XXX and I got raped,plain and simple.I verified my oil pressure, checked my rod and main bearings,replaced oil pump and still no change. Answer? My cam bearings are worn, apparently someone changed out the rod and mains because they showed no wear and plisti-gauged to "preferred" readings. Cam bearings are all thats left that could cause my low oil pressure. BTW I did have a cracked head. You described you "top off" the coolant bottle and it goes back down to where it was? that tells me you've got a coolant leak. If you checked the pressure with a mechanical gauge and it verified what your factory gauge tells you and you think its a little low, my suggestion is get a sample of the oil thats in the engine and have it tested for coolant contamination NOW to make sure before you further damage your bearings and end up replacing or rebuilding the whole engine. I dont mean to be so blunt and discouraging, but it is what it is

 

.....and any auto manfacturer that warrants there motors for 100K miles, using the recommended 5W20 or 0W20 oil, is crazy.

 

Wow, I really don't mean ti be a smart butt , did you read any of my posts? I clearly said I was talking about the
4.0l in our jeeps, unless you have a 2012 jeep Cherokee with a 100k Warranty ill shut my trap,

Take 0w20 and run it in your jeep for the 5-6 oic and send it to Blackstone and let me know how it feels to have basically ruined your motor

 

This whole discussion is about a jeep with a 4.0 in it, not a new car or a old ford a 4.0 with 100k miles

 

Who in their right mind would run anything but XW30 in the 4.0L, like the manual says.

 

I run 5w 40, cuz of the high mileage it hold up better for longer oic compared to 10w30, and yes I still have the Blackstone labs sheets to prove it so that's a fact haha, and I honestly don't know how it went this direction, I Belive it was a misunderstanding of what I was specifying oil for since this was a jeep forum and he was asking about oil for his jeep I figure hell we were talking about a jeep lol!

 

I highly suggest you use motor oil.


5 or 10W30 is fine.;

 

I lube with rotella 15w 40.

 

15w is kinda heavy no?

 

I rest my case. I will be back and check on you folks in a few months. Im sure the debate will still be raging

I will add one thing. I understand as mileage increases so does engine wear and with that clearances increase. Based on that I can see the theory behind using a heavier oil.
I myself prefer the theory of "if it isn't broke don't fix it". If I buy a vehicle and run xWx motor oil for 200K miles and its still going strong, why am I going to all of a sudden change. I truly believe oil choice is an opinion thing no matter how much research one can do. There are so many factors inside an engine that even with the best "tested" oil, an engine can still fail as quick as one using private labeled dime store oil.

 

mobil delvac 15w40hd:
cSt @ 40 celcius = 114
cSt@ 100 deg. celcuis = 15
VI = 137
pour point = -30 deg. celcius

mobil 1 0w40:
cSt @ 40 deg. celcius = 80
cSt @ 100 deg.celcuis = 14.3
VI= 187
pour point = -54 deg. celcius

mobil 1 5w30:
cSt @ 40 = 54.8
Cst@ 100 = 11.3
VI = 169
pour point = -45 celcius


decide which oil best suits your needs, cross reference other brands... the above info is most important (what helps me sleep at night), its also readily available to anybody. i dont need to read a million dissertations on bitog to get it right...