0W-40 in PUG 3.6

[ShadowsPapa]

OP, don’t take it personally. Shadowspapa hasn’t been this angry and verbose since the last oil thread. But that was days ago so you probably won’t see him repeat this behavior on a different thread anytime today

to everyone else, it would be interesting to learn the highest miles on reliable engines that used heavier oil

I don’t plan to change from OEM, but I welcome data

Not angry, just amazed at how ignorant people can be on something when there's overwhelming information to the contrary.
It's ADHD speaking, animation, not anger.

0W-20 is fine for daily driving, not for offroading in the desert heat or towing in heat.

Ambient temps don't matter, oil temperatures do.
40 weight is going to be too far - it's going to run hotter, and the parts it's supposed to cool will be running hotter. That's a given and proven by measuring SUMP temperatures. Can't go by the oil cooler temps, need to use the sump temps. That's the raw oil temperature coming off the parts and what counts.

Towing at 90-100 here is no different than towing in 90-100 degrees anywhere else. It's the engine and oil temperatures that matter.

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[Gladiator007]

Not angry, just amazed at how ignorant people can be on something when there's overwhelming information to the contrary.
It's ADHD speaking, animation, not anger.



Ambient temps don't matter, oil temperatures do.
40 weight is going to be too far - it's going to run hotter, and the parts it's supposed to cool will be running hotter. That's a given and proven by measuring SUMP temperatures. Can't go by the oil cooler temps, need to use the sump temps. That's the raw oil temperature coming off the parts and what counts.

Towing at 90-100 here is no different than towing in 90-100 degrees anywhere else. It's the engine and oil temperatures that matter.

Ambient temperatures don't matter, really? Have you checked your oil temp in the winter? When was the last time you saw 240 degrees in the winter?

 

[ShadowsPapa]

Ambient temperatures don't matter, really? Have you checked your oil temp in the winter? When was the last time you saw 240 degrees in the winter?

LOL - now you are getting silly and talking extremes.
I'm talking summer temps. People in TX and FL seem to believe that they need "thicker oil" because "it's hot down there".
Come on, compare summer temps, not something that's 70 degrees different outside.

I tow in hills and similar heat and my engine temperatures don't vary much from theirs. In fact, we've compared in the past and it's pretty close. So 80 here or 100 there - no big deal.
DUH, we have oil coolers, so of course you aren't going to generate more heat than the cooler can remove in winter.
Although I've seen elevated temps in the middle of winter with the plow on as it blocks air through the front of the Jeep.

 

[Gladiator007]

LOL - now you are getting silly and talking extremes.
I'm talking summer temps. People in TX and FL seem to believe that they need "thicker oil" because "it's hot down there".
Come on, compare summer temps, not something that's 70 degrees different outside.

I tow in hills and similar heat and my engine temperatures don't vary much from theirs. In fact, we've compared in the past and it's pretty close. So 80 here or 100 there - no big deal.
DUH, we have oil coolers, so of course you aren't going to generate more heat than the cooler can remove in winter.
Although I've seen elevated temps in the middle of winter with the plow on as it blocks air through the front of the Jeep.

SMH

 

[Gvsukids]

SMH

Too much work to type a complete sentence?

 

[ShadowsPapa]

The thickest 0W-20 is 9.0 cSt at 212 degree F, most 0W-20s are 8.2-8.4. Now imagine that at 240 degrees F, now we are talking 0w-16 or lower. 0W-20 is fine for daily driving, not for offroading in the desert heat or towing in heat.

And yet people have been doing it for years, since at least 2018.

Jeep says the cam issue is a part/materials issue.

So - whatever.

 

[AZ_Adventure_Clicks]

I was one of the people who (apparently mistakenly) believed running 0-40 is better... Especially because I frequently off-road in the Phoenix heat.
I've only run it for about 3k miles, however.
I'm one of the poor souls who've already had to replace my motor, And I'm not looking to go through that hell again.
Would there be any benefit to running a premium 0-20 or 0-30 (amsoil etc)?

 

[ShadowsPapa]

0-30 (amsoil etc)?

5w30 AMSOIL - signature.
Mobil 1 and Amsoil are supposedly less prone to viscosity breakdown over time than others. (to do with the base oils and chemistry from there)
Unless you see temps below 40 or so the 5w is likely fine.
If where you live in AZ gets colder when you start it up cold start, then 0W but my experiences in AZ suggest it's usually not that cold even at night in the areas I was in
There are other great oils, but AMSOIL is right up there and since YOU mentioned it - yeah.

 

[Hootbro]

Welcome to the 40 grade club. There is a few of us around here running 0W-40 or 5W-40 with regularity. My last run was Quaker State 5W-40 Euro and current fill is Delo 400 XSP 5W-40.

https://www.jeepgladiatorforum.com/...r-3-6l-oil-analysis.94589/page-2#post-1545583

 

[AZ_Adventure_Clicks]

5w30 AMSOIL - signature.
Mobil 1 and Amsoil are supposedly less prone to viscosity breakdown over time than others. (to do with the base oils and chemistry from there)
Unless you see temps below 40 or so the 5w is likely fine.
If where you live in AZ gets colder when you start it up cold start, then 0W but my experiences in AZ suggest it's usually not that cold even at night in the areas I was in
There are other great oils, but AMSOIL is right up there and since YOU mentioned it - yeah.

My cold tap water is 140°F.
Maybe in winter it might get that cold at night in Phoenix but it's rare.
I also believed the primary reason the rockers ate the cam was because I would allow it to idle a lot and this valtrain doesn't get oil back there unless it's moving. This belief was supported when I observed the oil coming up into the top of the head from only one location in the front when rotating the motor diagnosing what turned out to be a burnt valve. Yes, I know the grammar in that sentence was horrible.

 

[ShadowsPapa]

My cold tap water is 140°F.
Maybe in winter it might get that cold at night in Phoenix but it's rare.
I also believed the primary reason the rockers ate the cam was because I would allow it to idle a lot and this valtrain doesn't get oil back there unless it's moving. This belief was supported when I observed the oil coming up into the top of the head from only one location in the front when rotating the motor diagnosing what turned out to be a burnt valve. Yes, I know the grammar in that sentence was horrible.

Hopefully we don't get scored on grammar.
5w30 has been used, even recommended, in engines (including Jeep) since the late 1970s.
It was used in the first gen 3.6 engines.

You also hit why I like to keep these engines moving - don't baby them RPM-wise.

FCA's explanation for the cam issue - at least according to the TSB and stories about it - and what I gather from some techs, is..........

 

[AZ_Adventure_Clicks]

Their ultra expensive rocker arm redesign (price the JK rocker arm vs the JL) definitely didn't prevent it from happening so I'm gonna go with ENGINEERING ISSUE.

 

[ShadowsPapa]

Their ultra expensive rocker arm redesign (price the JK rocker arm vs the JL) definitely didn't prevent it from happening so I'm gonna go with ENGINEERING ISSUE.

They supposedly finally fixed the JK and other gen 1 engine issues with a change to the followers. The bearings were failing in the rollers.
So, same symptoms (cam and follower) but different causes.
The JK used simple followers on the intake, roller -type. There's a new part number as of 2019 that fixes the issue (bearing troubles, not a cam issue.)
in the upgrade engine, it's the high-lift portion that rubs on the lobe like a 1980s V8 or I6 lifter did.

In ours, the cams fail, in the JK, the rollers (bearings) failed, then took out the cams.

Whatever the case, the gen 1 is fixed with new parts as of 2019, and the TSB says as of August 2024 the upgrade engine is fixed with new parts.

Time will tell, eh?

But then - I'm the guy who runs performance cams in his cars and has NEVER used any additives in the oil, and never bought high-zinc oil or added any ZDDP to the oil and have never lost an engine or cam in anything I've built (or owned)
My 4.0 has a Comp Xtreme energy cam and MOPAR performance valve springs in it and I started it out with Mobil 1 from the first run, no additives, no high ZDDP.
So either I need to go buy lottery tickets as I'm the luckiest person in the world, or, I'm doing something not wrong.

 

[MT1]

Hey Gladiator007, Minty JL reported the same switch in another thread about two months ago, https://www.jeepgladiatorforum.com/forum/threads/oil-going-from-0w20-to-0w40.95836/. You might check on his experience.

To answer your question, "What could go wrong?", one thing come to mind.

If the 2025 3.6 PUG has a new manufacturing defect, not a continuation of the infrequent valve train failure in the 2020-2023 line, Jeep possibly could use your choice in viscosity to deny a warranty claim.

The other changes are the obvious decrease in MPG, and maybe higher oil pressure. But, I do not know the clearances, or if they would matter for the 3.6 PUG.

From memory, Amsoil's warranty is plainly worded. Before I would make the change, I would see if Amsoil's warranty would stand, with that change in viscosity.

I have thought about 0W30 just due to the heat, when rolling along at 10 MPH, at 105+ F, with the AC running. Even driving up the mountain to home at 30 MPG on paved road will get sustained oil temps above 230F.

 

[AZ_Adventure_Clicks]

Would this be the high lift portion?
I thought this was caused by the rocker.

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