The JL specs 0W30, JK is 5W20 or 5W30 if 20 is not available.

I attached a screenshot of my manual.

 

ok would a 5W40 be safe to use or is that going to thick?

 

A 0w40 or 5w40, or 10w40 will work, of those I'd use 0W40.

2012 calls for 5W30, which is what I would use instead of the 40 grades.

 

is that too thick, or if I was in a pinch and needed to is it safe to use, seeing as it is only 10 higher then the 5W30?

 

The fill cap on my 2012 JKU says 5W-30. I am using Mobile 1 5w-30. I do get valve chatter on cold starts for 1-2 seconds.

Chris

 

Try another brand, I have that same issue the one time I tried M1, swapped to another brand, problem solved.

 

Your 2012 calls for 5W30 viscosity. So why would you want to use a different weight?

 

In a warm climate, do people feel that 10W30 is the same as 5W30, or is 10W30 a bit heavier? Since the grading system is not that precise, does it depend on the brand?


The rationale for 10W30 would be fewer friction modifiers to get a lower volatility rating.

 

I agree with you, and I usually use 5W30 anyways, year round, but figured I would ask

 

My 710 cap stated 5W30, so that's what I use. I do use Penzoil full synthetic.

 

My 09 says 5w-20 but I get a dry start in the winter unless I run 0w-20.

 

Agreed, I favored the assumption of a brand being a continuum, because I'm an AMSOil fan, so I'm guessing my assumption is valid for them. I think there's a pretty noticeable difference in sound between their 0W30 and 10W30 Signature products.


For another sweeping generalization, I'm guessing the 5W spec is only needed for Canada and the upper mid-west. I'm guessing most of the country is warm enough for a 10W30 full synthetic. Unfortunately, the OEMs are pushing thinner oils than are needed, for gaming CAFE.

 

well I live in the good old New England area so when we get our cold we get our cold in snaps of its ok to "eff this shite" levels of cold, and I use the 5W40 in my truck (granted its a diesel) and it works well in the cold so I was asking in those manors, I guess, but at least I got what I needed and will read more on the oil in question

 

lots of info here: https://www.bobistheoilguy.com/
and here: https://www.bobistheoilguy.com/motor-oil-101/,
not to mention here too: https://www.bobistheoilguy.com/putting-the-simple-back-into-viscosity/

 

Anyone use Shells Rotella? That stuff was considered magic amongst the ford ranger community (and SV650 motorcycle community), plenty of rangers driven further than the moon. Looks like they produce a 5w30 that meets ms6395 now too

https://rotella.shell.com/en_us/products/gas-truck-synthetic-engine-oil.html

 

I use shell rotella t6 5w40 diesel engine oil in my 2012, works great and silent. Has been ran hard at times and just passed 100k, original cylinder heads to!

 

Rotella 5w40 is a great oil. HDEO oils will work fine in the 3.6L, although they are not what Chrysler recommends for the engine. The HDEO oils tend to be on the "thicker" side of the grade and have a different additive pack, than PCMO. Some claim they have better cleaning properties, and some other benefits. I recently changed from Pennzoil Ultra 5W30 to Mobil 1 ESP 0W30. Which is a European Certified oil for gas and diesel engines. It was recommended by a few oil guru buddies of mine. So far so good. It will be a while, probably a long while but I will get a UOA and compare it to the PU, which I was also happy with.

 

Few seconds of cold start up chatter is characteristic for any motor with lash adjusters.
The colder it gets the noisier it becomes, lash adjusters are notorious for very slow oil flow, so basically if oil is leaking out after let say overnight parking and then at startup is pumped back in, its better than if it stays inside the adjuster and doesn't leak out, this "tight" adjusters have more chances over time to get stuck, glued by oil residue and therefore stop doing their job, potentially damaging rocker arms and cam shafts.

 

Lifter bleed down is not good.

Not on the LS - rockers are torqued down, no lash adjustment. Never had the issues before I ran M1 or after I drained it out and replaced it.

No matter how cold I never had that Issue until I ran M1, even at -40c. Vehicles are parked outside, never plug them in.

M1 oil is over rated.

 

IDK about -40C, the lowest temp I've started a motor it was -25C maybe -27C and it was clicking and ticking for half an hour until it warmed up.

 

Use of diesel oil in a gas engine

Some people say that diesel oil is fine in a gas engine but the load carrying capability of diesel oils is almost half of what gas engine oils are. Diesel engines are built with heavier load bearing surfaces than gasoline motors. This came from 540 Rat's blog on engine oils. I have no other data to go on other than what I have read on this guy's analysis. He has put a lot of effort into gauging motor oil performance. Just a little food for thought.

Summary
Thermal Breakdown BEGINS SOONER with Diesel oil, than with gas engine oils, which is not desirable for High Performance gas engine usage. And as you can see by looking at this short list of “high zinc” gas engine oils, or by looking at my complete Wear Protection Ranking List, there are many, many gas engine oils available that are FAR SUPERIOR to the best Diesel oils in terms of wear protection. Therefore, using Diesel oils in high performance gas engines is NOT the best choice, if you want superior wear protection with plenty of margin of safety (extra reserve wear protection above what the engine typically needs).

.
For those who have used Diesel oil in High Performance gas engines for years without issue, you were able to do that only because the wear protection required by the engines, never happened to exceed the oil’s capability. But, you were clearly running a MUCH LOWER margin of safety than you would have been, if you’d used a much more capable gas engine oil instead. So, if you’ve been using Diesel oil in High Performance gas engines, you may want to rethink what you’ve been doing and consider upgrading to one of the far better gas engine oils.

This statement is from https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/
This guy is a mechanical engineer doing independent testing of motor oils. He is a race car engine builder also.

 

Some people say that diesel oil is fine in a gas engine but the load carrying capability of diesel oils is almost half of what gas engine oils are. Diesel engines are built with heavier load bearing surfaces than gasoline motors. This came from 540 Rat's blog on engine oils. I have no other data to go on other than what I have read on this guy's analysis. He has put a lot of effort into gauging motor oil performance. Just a little food for thought.

Summary
Thermal Breakdown BEGINS SOONER with Diesel oil, than with gas engine oils, which is not desirable for High Performance gas engine usage. And as you can see by looking at this short list of “high zinc” gas engine oils, or by looking at my complete Wear Protection Ranking List, there are many, many gas engine oils available that are FAR SUPERIOR to the best Diesel oils in terms of wear protection. Therefore, using Diesel oils in high performance gas engines is NOT the best choice, if you want superior wear protection with plenty of margin of safety (extra reserve wear protection above what the engine typically needs).

.
For those who have used Diesel oil in High Performance gas engines for years without issue, you were able to do that only because the wear protection required by the engines, never happened to exceed the oil’s capability. But, you were clearly running a MUCH LOWER margin of safety than you would have been, if you’d used a much more capable gas engine oil instead. So, if you’ve been using Diesel oil in High Performance gas engines, you may want to rethink what you’ve been doing and consider upgrading to one of the far better gas engine oils.

This statement is from https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/
This guy is a mechanical engineer doing independent testing of motor oils. He is a race car engine builder also.

I recall a good discussion on a message board I frequent some years ago regarding this. The engines in our Jeeps are far from high performance engines, or engines built for racing. In a high performance engine a racing oil would be much better suited than an HDEO, or a PCMO. However it would have to be change more frequently, and is not well suited for the engines in our Jeeps. In the case of the Mobil 1 oil I mentioned it is rated for gas and diesel engines.

Edit: I just realized you might be confusing HDEO with diesel engine oil. HDEO refers to Heavy Duty Engine Oil. The Rotella mentioned would be fine.

 

I'm simply looking at the data provided, one has twice the load carrying capability of the other, a very good margin of protection. I'm sure the Shell people would like to include as many applications as possible for sales. I've run T6 in my New Holland tractor for 17 years and it still runs like new. I think it's good oil but I'll choose QT 5w-30 for my gas motors.