5W 30 versus 0W 20

[SCJeeps]

It needs to be understood that switching oil viscosity is not as simple as “it sounds better” or is smoother. The engine is a system which uses the oil for various functions in different components. Oil selection is a compromise among these components. For instance oil is used for lubrication of sliding in the pistons, it is used as lubricant for journal bearings , it is used for lubricant of valve train components, it is used as hydraulic oil for controlling the VVT, it is used as a lubricant for the timing chain, and so on. The point is changing the oil viscosity is not as simple as it might positively affect one portion of the system but not another.

It should not be assumed that just because at one time they called for usage of 5w-30 that it is fine now. The pentastar “upgrade” engine which became available in the wrangler in 2018 did have changes that merited the revised oil specification change. I’m sure there was pressure for CAFE standards as well to help reduce friction, but again I assure you that thousands if not millions of hours of testing went into the selection of the oil viscosity for the “system”.

All that done and said : my recommendation is to run a quality oil that meets API - SP. I am also a big proponent of using quality synthetic oils from the major oil blenders; Mobil, Shell, Valvoline, etc. Lastly It is more important to properly maintain and complete more frequent oil changes. The difference between 0w-20 and 5w-30 is likely not major, run what you are comfortable with but select a quality oil and change it frequently.

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[bd100]

A lot of people trust the factory engineers for 0W20, but not for the oil life display. Or the "lifetime" transmission fluid. Etc.

Changing early is probably a good thing, but in some circumstances 5W30 may also be good (hot weather, towing). 0W20 may be better in sub-zero weather. For most of us it may not matter as long as you change it often-ish.

Some argue that thicker oil for a quieter engine is just masking the problem, while others may argue that it delays or prevents the problem. We can't really know until someone runs long-term tests. This latest TSB seems to say that they had a manufacturing issue for years, so who knows anything?

 

[roaniecowpony]

I don't put much credence in anything Stellantis does or publishes. They haven't earned that from me.

 

[JL ME]

It needs to be understood that switching oil viscosity is not as simple as “it sounds better” or is smoother. The engine is a system which uses the oil for various functions in different components. Oil selection is a compromise among these components. For instance oil is used for lubrication of sliding in the pistons, it is used as lubricant for journal bearings , it is used for lubricant of valve train components, it is used as hydraulic oil for controlling the VVT, it is used as a lubricant for the timing chain, and so on. The point is changing the oil viscosity is not as simple as it might positively affect one portion of the system but not another.

It should not be assumed that just because at one time they called for usage of 5w-30 that it is fine now. The pentastar “upgrade” engine which became available in the wrangler in 2018 did have changes that merited the revised oil specification change. I’m sure there was pressure for CAFE standards as well to help reduce friction, but again I assure you that thousands if not millions of hours of testing went into the selection of the oil viscosity for the “system”.

All that done and said : my recommendation is to run a quality oil that meets API - SP. I am also a big proponent of using quality synthetic oils from the major oil blenders; Mobil, Shell, Valvoline, etc. Lastly It is more important to properly maintain and complete more frequent oil changes. The difference between 0w-20 and 5w-30 is likely not major, run what you are comfortable with but select a quality oil and change it frequently.

I agree with this. I think my 3.6 would have been just fine running 0w-20 but when I switched to 5w-30 my motor is telling me thankyou and sounds, runs allot better

 

[Pape]

I know theres been a lot of discussion on here in the past about preferred oil for the 3.6 Pentastar since Jeep changed it to a 0W 20. Has anyone had a successful strategy ie 1) Run 0W 20 until 60k then switch to 5W 30?
2) Run 5W 30 from the get go and bet on the come as to warranty? (Less likely to need it)
3) Stay with 0W 20 because 5w 30 wont make that big of a positive difference?
4) when you hear the Pentastar has potential to make it 300k and above,no chance with 0W 20 right? Must go to 5W 30 at some point?
5) as i understand it, Jeep only changed it for EPA emissions tests and a little bit of mileage ( about as much as the start stop)
Would appreciate your experience and how many miles you made it to without a major issue (successful strategy) thanks

This boil down to personal preference. So far from my testing PU 0w20 did less engine wear than PUP 5w30 but I do not recommend to base any judgment out of it as the test parameter are different. The thicker oil was run in the summer while the thinner oil was run in the winter. Currently running the thinner oil in the summer and see how it go for wear.

The only thing I can recommend is get your own data and do your own judgment: ya oil analysis.

 

[Willys.JLU.2021]

This boil down to personal preference. So far from my testing PU 0w20 did less engine wear than PUP 5w30 but I do not recommend to base any judgment out of it as the test parameter are different. The thicker oil was run in the summer while the thinner oil was run in the winter. Currently running the thinner oil in the summer and see how it go for wear.

The only thing I can recommend is get your own data and do your own judgment: ya oil analysis.

I appreciate your thoughts..im currently running Pennzoil Ultra 0W 20 as well. I dont think i will change anything until i go past the warranty (60k) then will revisit..thx again

 

[DaltonGang]

I don't put much credence in anything Stellantis does or publishes. They haven't earned that from me.

I don't trust much of what Stellantis says either, or those representing them.

I agree with this. I think my 3.6 would have been just fine running 0w-20 but when I switched to 5w-30 my motor is telling me thankyou and sounds, runs allot better

If the top end is happy, and quiet, then hopefully the lifters and cams are less likely to destroy each other.

 

[CarbonSteel]

I don't put much credence in anything Stellantis does or publishes. They haven't earned that from me.

 

[CarbonSteel]

But there is a small problem, the 5w part of 5W30 gets oxidized to 10w with use, so we end up with 10W-20 at 5,000 mile OCI That's why I'm in a hurry to change my oil. Oil science is crazy.

How do you know that? Did you perform a VOA to set the baseline on the virgin oil? Curious as to how you identified oxidation as the cause for the increase in viscosity.

 

[CarbonSteel]

Problem is their Super Car oil doesn't shear, instead goes up in viscosity. So 0W-40 might become a scary 5W-50, and 0W-30 a 5W-40. That won't be too much for our 3.6? 🫣
I saw that guy Overkill's UOA on BITOG, Super Car 0W-20 started with 8.5 and thickened to 9.3 after 5000 miles and over 10 after 7000 miles. It is one wild oil.

I would raise more than an eyebrow at any oil that increases in viscosity over mileage/time--particularly one that does it with no apparent reason. Engine oil almost always loses viscosity during use --it does not gain it--unless it is used LONG past its serviceable life. It would cause me to question the chemistry of the oil and/or the manufacturing methods.

No mainstream oil that I have ever used increased in viscosity unless the engine was causing it due to a mechanical problem or by design such as soot from a diesel. Speaking only for me, the cost of HPL is not worth it...

 

[tk1700]

This boil down to personal preference. So far from my testing PU 0w20 did less engine wear than PUP 5w30 but I do not recommend to base any judgment out of it as the test parameter are different. The thicker oil was run in the summer while the thinner oil was run in the winter. Currently running the thinner oil in the summer and see how it go for wear.

The only thing I can recommend is get your own data and do your own judgment: ya oil analysis.

I'm curious, how did you measure engine wear?

 

[Jeep Junkie]

I would raise more than an eyebrow at any oil that increases in viscosity over mileage/time--particularly one that does it with no apparent reason. Engine oil almost always loses viscosity during use --it does not gain it--unless it is used LONG past its serviceable life. It would cause me to question the chemistry of the oil and/or the manufacturing methods.

No mainstream oil that I have ever used increased in viscosity unless the engine was causing it due to a mechanical problem or by design such as soot from a diesel. Speaking only for me, the cost of HPL is not worth it...

They say when oil is being used, there's a battle between oxidation and shearing going on. Oxidation thickens, shearing thins and shearing is faster. With HPL No VII and Super Car, there is no shearing so oxidation slowly thickens the oil. That BITOG guy Overkill's UOA's are available

 

[Jeep Junkie]

How do you know that? Did you perform a VOA to set the baseline on the virgin oil? Curious as to how you identified oxidation as the cause for the increase in viscosity.

They said this on BITOG. 0w becomes 5w and 5w becomes 10w. Used 0w20 oil is no longer 0w20, it is something like 5w16.

 

[Pape]

I'm curious, how did you measure engine wear?

By measuring the PPM of wear metal in the use oil. Give you a estimate as this only provide count for small particles. A look at the filter is also recommended if you want to be thorough.

 

[roaniecowpony]

I recall when a friend, an engineering manager at Honda, set up a wear test for oils, sometime in the 80s. They had a bunch of Honda industrial engines that had been "blueprinted". That is they were all as close to the same as possible and all the measurements and surface roughness were recorded for each engine. All the engines were run on natural gas, temperatures of the oil were controlled to match each other, at elevated temperatures to accelerate the test results.

Mobil 1 was the only synthetic in the test, since synthetics were somewhat novel or not mainstream at the time.

I'll cut to the chase. The Mobil 1 turned to a type of rubbery, translucent, plastic. Why? My feeble understanding is that the natural gas cross-linked with the synthetic oil, at elevated temperature.

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