Oil - going from 0w20 to 0w40

[Maximus Gladius]

but this will not be settled until I contact Jeep

It may not be settled even if you contact them. You’re expecting a lot, even to think they’ve read their own published material. The manuals are for the vehicle own to interpret. Want to see the author short circuit, ask them to clarify what they write.

The scariest thing a dealership experiences is a vehicle owner walking in with the book and being asked to clarify or explain in detail fashion some ambiguity in the book. I tried that once. Even had a meeting with the GM of one fine Chrysler dealership to have him explain something in the book. He said to me, in his very advanced way of clarifying my question,… “I haven’t read the manual and I’m not about to start. Get out of my building”. …and I never went back and never will.

If you come at them with the way you do that is very precise and analytical that backs your question, you will short circuit them. You must dumb down your approach and not make their job hard.

Good luck! (Would love to be a fly on the wall of the poor sap that gets your email)

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[g2020]

It may not be settled even if you contact them. You’re expecting a lot, even to think they’ve read their own published material. The manuals are for the vehicle own to interpret. Want to see the author short circuit, ask them to clarify what they write.

The scariest thing a dealership experiences is a vehicle owner walking in with the book and being asked to clarify or explain in detail fashion some ambiguity in the book. I tried that once. Even had a meeting with the GM of one fine Chrysler dealership to have him explain something in the book. He said to me, in his very advanced way of clarifying my question,… “I haven’t read the manual and I’m not about to start. Get out of my building”. …and I never went back and never will.

If you come at them with the way you do that is very precise and analytical that backs your question, you will short circuit them. You must dumb down your approach and not make their job hard.

Good luck! (Would love to be a fly on the wall of the poor sap that gets your email)

I'd like to talk to ultimate approver of the copy for the revisions to the online version of the 2020 owner's manual. Then I might learn whether this is Jeep's way of pulling a Houdini and escaping from the CAFE straightjacket.

 

[Maximus Gladius]

I'd like to talk to ultimate approver of the copy for the revisions to the online version of the 2020 owner's manual. Then I might learn that this is Jeep's way of pulling a Houdini and escaping from the CAFE straightjacket.

If anyone will find this individual, it’s you. Holding my breath….

 

[Hootbro]

It is obvious that I believe this is more than just a list of grades that API certifies. If they were going to stick exclusively to 0W-20, they would not have revised the 2020 owner's manual. Also, if this were just a list of grades that API certifies, they would not have omitted 5W-20 and 10W-30 from the 2026 owner's manual. The starburst is still right there on the front label of Mobil 1 EP 5W-20.

Also see the justification in a different post. This information has been out there for more than a year.

In all cases, 0W-20 is still recommended.

I will not consider this to be settled until I contact Jeep.

I think you are projecting something that is just not there and is basically a change of their boiler plate ad copy in the owners manual. I looked through all years of the JT OM's and it seemed to switch in 2022 to the three listed grades with 2021 and prior having the five listed grades.

For point of referenced, since I have owned a 2018 RAM 2500, I checked their owners manual and they had the same switch over from 5 grades listed in 2021 and prior, and then changed to 3 grades listed for the API Starburst symbol for 2022 through current 2026.

If I followed your logic from my 2018 RAM 2500 owners manual, I could theoretically run 0W-20 without consequence in my 6.4L HEMI that calls for 0W-40 as "recommended" which I highly doubt is the case.

 

[g2020]

I think you are projecting something that is just not there and is basically a change of their boiler plate ad copy in the owners manual. I looked through all years of the JT OM's and it seemed to switch in 2022 to the three listed grades with 2021 and prior having the five listed grades.

For point of referenced, since I have owned a 2018 RAM 2500, I checked their owners manual and they had the same switch over from 5 grades listed in 2021 and prior, and then changed to 3 grades listed for the API Starburst symbol for 2022 through current 2026.

If I followed your logic from my 2018 RAM 2500 owners manual, I could theoretically run 0W-20 without consequence in my 6.4L HEMI that calls for 0W-40 as "recommended" which I highly doubt is the case.

Here's the copyright (2022) & version on the last page of the 2020 manual that I downloaded in April 2025.

This at least narrows the reason for the revisions. I said that this was the result of loosening CAFE standards. Google AI said that these changes were related to improvements in preignition, but then Google AI admitted that it was hallucinating (I always ask).

It would be interesting to know when the printed manuals started listing additional grades or grades that API certifies. I know that they didn't start doing this until after September 2019.

If I haven't already done so, I will add some comments in my recent posts to make sure people know this is not settled.

 

[Jrgunn5150]

Lol

 

[DanW]

Your finding about grades being no different outside of the U.S. means The Motor Oil Geek will need to change part of his video (starting at 0:54).

Note: My opinion about the five (5) grades is my interpretation. I am still investigating this with Jeep and the issue is not settled. 0W-20 is recommended in the owner's manual.

I still think that Jeep meant what they said when they added viscosity grades to the revised 2020 owner's manual. 0W-20 is recommended and four other grades are listed. However, there are some differences between the advice in the revised 2020 owner's manual and the 2026 manual. I plan to contact Jeep about the differences.

- Changes: In my opinion, the changes are a result of loosening CAFE standards (crossed out because the revised 2020 owner's manual is copyright 2022)
- Inconsistent viscosity grades: While there are three grades in common, advice on viscosity grades for the 3.6L engine in the Jeep Gladiator is different for the two examples discussed in this post

Assumption: A viscosity grade listed in the owner's manual may be used; see fact #3 in key facts about motor oil compliance and viscosity grades. I think that this is a safe assumption, but this will not be settled until I contact Jeep.

The advice on 1) page 251 of the revised 2020 owner's manual and 2) page 238 of the 2026 owner's manual (below) are written differently. In the revised 2020 manual, there are no conditions mentioned for the other grades listed. However, in the 2026 manual, the grades are grouped by API trademark type and the reader is redirected to page 283.

Viscosity grades listed in revised 2020 owner's manual:
- 0W-20, 5W-20, 0W-30, 5W-30, and 10W-30
- Unlike the 2026 owner's manual, this advice ends here (no continuations)

>>> Grades in common: 0W-20, 0W-30, and 5W-30 (in both revised 2020 owner's manual and 2026 manual)

Viscosity grades listed in 2026 owner's manual:
- API Starburst trademark: 0W-20, 0W-30, and 5W-30 (5W-20 and 10W-30 are not listed in 2026 owner's manual)
- API Donut trademark: 0W-40 and 5W-40 (0W-40 and 5W-40 are not listed in revised 2020 owner's manual)

2026 owner's manual, page 238:

2026 owner's manual, page 283:

It does not specify those oils. Read elswhere in there and you will see that it still recommends 0w20. That doesn´t say anything other than noting the starburst symbols and giving what I would interpret as an ¨ok¨ to use those other weights. Even though it does not really say that. It just implies it.

This version of the Pentastar did all of its development and certification testing on 0w20 when it was designed. That was done from the hottest to the coldest environments, and everything in between, in their test program.

There once was a time with the original gen 1 Pentastar when 5w30 was recommended in places like Europe. That is not the case with the PUG generation of this engine.

Even in the Middle East, 0w20 was originally recommended for the PUG.

The good news is that there won´t be a warranty denial for using these additional grades. It would be very hard to do that.

It is wrong to say, however, that 5w30 or any other grade was originally recommended for the PUG. Or as others have said, that it was designed and validated on anything other than 0w20.

 

[g2020]

It does not specify those oils. Read elswhere in there and you will see that it still recommends 0w20. That doesn´t say anything other than noting the starburst symbols and giving what I would interpret as an ¨ok¨ to use those other weights. Even though it does not really say that. It just implies it.

This version of the Pentastar did all of its development and certification testing on 0w20 when it was designed. That was done from the hottest to the coldest environments, and everything in between, in their test program.

There once was a time with the original gen 1 Pentastar when 5w30 was recommended in places like Europe. That is not the case with the PUG generation of this engine.

Even in the Middle East, 0w20 was originally recommended for the PUG.

The good news is that there won´t be a warranty denial for using these additional grades. It would be very hard to do that.

It is wrong to say, however, that 5w30 or any other grade was originally recommended for the PUG. Or as others have said, that it was designed and validated on anything other than 0w20.

0W-20 is recommended by Jeep. I never said that 5W-30 or any other grade was originally recommended for the PUG.

I am still going to contact Jeep about this because at least one Jeep dealer insists that 0W-20 is required (see this link, 3rd paragraph). I don't agree with this dealer's statement (changing "recommended" to "required"), but it's out there.

To me, a grade being "listed" in the manual is the same as saying that it is "OK" to use. I am just calling out what has been rarely mentioned on this forum, which is that other grades have been listed since 2022.

I've put a note in big bold font at the beginning of each of my posts on this topic to make sure folks know that I'm still looking into it. Also, you can see my take on the PUG engine in my post on motor oil compliance.

Meanwhile, 0W-20 is recommended by Jeep.

 

[White Eagle]

So, you are saying 0-20w is recommended by Jeep ?

 

[Jrgunn5150]

Lol

 

[JTGuy]

I really think that the oil weight thing is really BS . They have ulterior motives for what they say. I am going to run the oil I have stated before. 5-30 torso full synthetic. I believe it hs more protection than 0-20 of anything. If the difference between 0-20 and 5-30 makes a huge difference then we are all screwed. Our engines are all going to fail.

 

[DanW]

Ok, this going to be a highly debated thread for numerous reasons and I get it. Yes, I have always been an advocate for using what the manufacturer states. BUT it seems both Jeep and GM have screwed the pooch on this topic.

First, the 3.6 only on bank 2 the cam getting chewed up by the rockers once the Teflon coating wears away the damage begins as we know......why is this issue not an issue on the other 3 cams and rockers. Analysis would lead me to believe poor oiling or pressure.

Second case point, the recent recall on all GM vehicles equipped with the LT based 6.2 why is this relevant to Jeep and the 3.6.......both from the factory use 0w20 oil. I have watched hours of video from professional technicians and read several articles on the diagnosis procedures.

GMs diagnostic procedure to determine an issue or immenant engine failure is scanning for the Crank to Cam timing/correlation, if exceeds a specified threshold......engine replacement if it hasn't already failed. IF the values are within specification........drain engine oil, replace filter and fill with 0w40. Yes, that's the fix and is how ship now right off the assembly line.

So.......I will be a test monkey and I'm switching to 0w40 with today's oil change. Anything I can do to prolong engine life is a win with these 3.6s.......and there is currently a national back order on the cams with dealers saying 6 to 8 weeks.

Call me dumb, damn that's a good idea or state an educated or well articulated thought.

So you bought into parts of what Trailrecon´s mechanic said, but not all of it.

First of all, he said ALL Pentastars rockers/lifters fail because of that. You bought it. It´s wrong. They do not all fail. Many go hundreds of thousands of miles without an issue with them.

Secondly, the coating on the parts in the PUG Pentastar is not Teflon. It has a name, sometimes called DLC (Diamond Like Coating). It was made to mitigate wear due to the start/stop system. There´s another name for it that escapes me, but I´ll find it and post it.

Third, the mechanic said the oil weight did not make a difference. So it doesn´t make sense to believe him on the cause and then not believe him on that.

Here´s another reason not to believe him. My buddy´s 2014 JK has well past 260,000 miles on 5w20 oil. SO that pretty much crushes the idea that they all fail and that 20 weight oil causes it.

I´m not going to get deeply into the debate. Just wanted to clarify a few things. That dopey Trail Recon video has spread all kinds of misinfo and info that are just opinions of one mechanic. He´s probablhy a good mechanic. But he also spewed a lot of shop BS. Not just about the engines, either.

 

[Hootbro]

So you bought into parts of what Trailrecon´s mechanic said, but not all of it.

First of all, he said ALL Pentastars rockers/lifters fail because of that. You bought it. It´s wrong. They do not all fail. Many go hundreds of thousands of miles without an issue with them.

Secondly, the coating on the parts in the PUG Pentastar is not Teflon. It has a name, sometimes called DLC (Diamond Like Coating). It was made to mitigate wear due to the start/stop system. There´s another name for it that escapes me, but I´ll find it and post it.

Third, the mechanic said the oil weight did not make a difference. So it doesn´t make sense to believe him on the cause and then not believe him on that.

Here´s another reason not to believe him. My buddy´s 2014 JK has well past 260,000 miles on 5w20 oil. SO that pretty much crushes the idea that they all fail and that 20 weight oil causes it.

I´m not going to get deeply into the debate. Just wanted to clarify a few things. That dopey Trail Recon video has spread all kinds of misinfo and info that are just opinions of one mechanic. He´s probablhy a good mechanic. But he also spewed a lot of shop BS. Not just about the engines, either.

I do not think that quote of Minty JL's post from a year ago has aged well. From what I gather, he has had his right bank replaced and that did not take long term and is now having his engine replaced and looking to sell his JT after that.

Just about every "trick" has been played with regards to oil type, grade, and interval and every one of them has had people still have issues regardless.

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