0W20 engine oil?

[dabolay]

I saw an interesting reference that suggests FCA went with 0W20 motor oil in my 2018 Wrangler V6 in order to meet competitive miles-per-gallon fuel goals...and that this lighter oil might not offer the protection that 5W20 or 5W30 oil provides. Your thoughts please?

Is 0W20 bad for your engine? Here's a quite recent article, not a Jeep engine mind you... but an article about how 0W20 weight oil is bad for your engine. https://pickuptrucktalk.com/2025/02/is-0w20-bad-for-your-engine-million-mile-tundra/

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[roaniecowpony]

Over 90k with factory spec. Honda did similar back in 2011 on engines made before 2011 got the service update to 0w-20 on oil changes. IIRC there were a few oiling issues prior to 2011 (2006 - 2010). Variable valve timing actuators could be effected by contaminants and thicker oil. some reported ticking and oil consumption. Tell those who push 0w-20 as bad here... Honda has more engines running on 0w-20 than Jeep and have higher RPM redlnes. Honda never blinked when including some earlier Gen engines in the mix. oh by the way Honda is no slouch on long running engines.

Makes you wonder how FCA could mess this valvetrain up so badly. Wish my JL had a Honda engine...or a LT.

There was a FCA 3.6L minivan with extreme miles recently, as well. I think those extremely high mile examples show a trend. The trend I see is: extremely long trip, continuous use, low number of start-ups/mile, manufacturer recommended maintenance. If we could see the start-ups vs miles, on valvetrain failed engines vs trouble-free engines, I think it would be enlightening.

 

[azjl#3]

Use 0w20 factory spec. Then I add Lucas viscosity modifier. 12 years, 7 engines, over 300,000 miles. Not one tick.

 

[roaniecowpony]

Use 0w20 factory spec. Then I add Lucas viscosity modifier. 12 years, 7 engines, over 300,000 miles. Not one tick.

You're effectively making thicker oil.

 

[jav_eee]

GM recalled their 6.2L. Dealers are instructed to check for engine issues and if none are present at inspection then they instruct the dealership to change the oil from 0w-20 to 0w-40 and put it back on the road. Hmm.

 

[Remorseless]

You need a high film strength like only 85w140 can offer

 

[roaniecowpony]

GM recalled their 6.2L. Dealers are instructed to check for engine issues and if none are present at inspection then they instruct the dealership to change the oil from 0w-20 to 0w-40 and put it back on the road. Hmm.

And the only oil spec'd is Dexos R which is in the list below. The M1 Supercar 0w40 I have in my 3.6L JL is on the list.

 

[Bearded_Dragon]

You need a high film strength like only 85w140 can offer

That's what I run in everything; oil, coolant, brakes, transmission, etc.

 

[azjl#3]

I don't want to counter the supposed pentastar engineer, but..... valve stem seals prevent oil from going down valve stem after shutdown, resulting in smoke at startup, and manages amount of oil on valve stem while running. If you designed a motor needing high rpm to properly oil the valves, you screwed up. Color me skeptical. But I'll Rev it up occasionally more to have high rpm wear vs low rpm wear. Not lubricate valves.

 

[azjl#3]

You're effectively making thicker oil.

Yes.

And staying in warranty requirements, while increasing viscosity. I have never heard of an issue other than mpg, by using a higher viscosity. And per the supposed engineer, higher viscosity will help at the rpm the motor lives at, sub 2,000 rpm.

All of this is moot if you use amsoil of any viscosity.

 

[Pape]

These oil Threads having been going on, since the origination of vehicle Forum. Everybody has an opinion, but what is it based on, is what is missing in most..LOL
THE BELOW IS FROM THE DESIGN ENGINEER THAT WAS INVOLVED WITH THE PENTASTAR 3.6 ENGINE. This will show one, what the different viscosity's benefit, or maybe not. But it is from an engineer with the hands on 3.6 development, not just a guess Enjoy:

Nice! As a former Pentastar design engineer I am slightly bias, but the engine is really high quality. Few points from the development using tens of millions of dollars in analysis and testing regarding the oil and durability..... The lighter oil was chosen mostly for fuel economy BUT engineering is the science of compromise. You help one thing but hurt another. A thicker oil will reduce timing chain and tensioner wear because the center timing chain idler doesn't go fully hydrodynamic till about 1650rpm on 5w-20. So, a thicker oil will lower that number slightly and with general loads/speeds the engine spends a lot of time around 1500-1750 rpm with the 8 speed. So thicker oil is a win there. Additionally, the earlier engines had what was called the "McDonald's Arches" in the idler bearing which was intended in making a more uniform distribution but in actuality acted as a knife edge. This design was changed around 2014 to a smooth bearing. So overall timing chain issues will likely follow the 2011-2014 engine years more than 2014+. Where you lose.... The head is very complicated with a Type II valve train. Meaning lots of things to pressurize and pump up at start up. A thicker oil didn't do so well here (on long sit times +cold start) and contributed to a overall increased engine wear especially in the head and cam bearings. Last point. This engine needs occasional WOT runs if you want it to last. Granny cycling is bad for it. So bad for it we actually created a new granny cycle test during the cylinder #3 misfire issue. The highest wear is in the valve guides, because of tight valve stem seals (for emissions, reduce oil burn). They basically dry out. When you go WOT/high rpm/load you get some fresh oil in there and this keeps the wear down. Thicker oil might not help this condition but we also change the valves/guides/seals in 2014+. Not sure the impact. Cheers! Kevin PS. Turn off stop start and do not run e85 if you are concerned about engine wear. Eats the engine alive.

Maybe you also want to add the second part of this where he say he quit before de redesign that is in the JL and what is it area of expertise in the engine

IMO: we have here the statement of a engineering who is officially in the know for the block portion of the timing and have hearsay about the head where our issue are mostly.

Here is a simple way to look at it:

1. 0w30 is thicker than 0w20
2. 0w30 is the same viscosity at 212 as 0w20 at 194
3. Operating temperature for the engine is between 190 & 230
4. With the temperature variation both oil will be running the same viscosity at one point or a other during the operating temperature

There you go, running thicker oil is not a issue as they both provide the same viscosity within the operating temperature of the engine.

 

[Tncdrew]

Run whatever you want.

What I find particularly hilarious regarding this newly announced recall/stop order for EVERY GM L87 6.2L gas engine (2021-2024), is that...
After passing the dealer inspection of said engines, the technical bulletin instructs the dealer tech to replace the oil cap with one that calls for 0W-40, (on an engine that previously required 0W-20)...

Could mean absolutely nothing for us, but really makes ya think

 

[roaniecowpony]

Yes.

And staying in warranty requirements, while increasing viscosity. I have never heard of an issue other than mpg, by using a higher viscosity. And per the supposed engineer, higher viscosity will help at the rpm the motor lives at, sub 2,000 rpm.

All of this is moot if you use amsoil of any viscosity.

I'm warranty-less anyway. I use my flavor of the month. Currently running M1 Supercar 0w40. Started it this morning, about 8-9k on this engine since new. It was purring, or about as close to purring as a Pentastar gets. I'm still wanting for a 5.3 LT engine. Nice torque, good mileage, enough power for me.

 

[Tncdrew]

I'm warranty-less anyway. I use my flavor of the month. Currently running M1 Supercar 0w40. Started it this morning, about 8-9k on this engine since new. It was purring, or about as close to purring as a Pentastar gets. I'm still wanting for a 5.3 LT engine. Nice torque, good mileage, enough power for me.

My warranty is about expired, but don't really care. I've been using the M1 Euro Car Formula 0W-40 for awhile now. That, plus my engine RARELY running over 200° makes for a very happy sounding 3.6.

 

[CarbonSteel]

0w30 is the same viscosity at 212 as 0w20 at 194.

Do you have a reference for this?

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