Changing oil weight

[Jeep Junkie]

Hey,

So I’ve read a few things about swapping from 0w-20 to something a little thicker in the 3.6L. I’m due for an oil change and was wondering if I should swap to a 5w and if now is a good time with winter almost here. We live in TN so winter isn’t too harsh but it can get to the double and single digits occasionally. I’m at 58k miles on my stock 21 JLUR.

Also, plan to replace t case and diff fluids. Not sure if myself or the shop will do it, depends on how much they quote. Other than a “multipoint” inspection, is there anything else I should do or check?

Any advice is appreciated!

Bro, I'm running the oil meant for the turbocharged V8 Mercedes G Wagon, Pennzoil Platinum Euro 0W-40. In a couple of weeks I will report how things went

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[roaniecowpony]

But Engineers also say follow the oil life monitor while running the crappiest MS-6395 0w20 out there, change the coolant after 100,000 miles, and never change the transmission fluid 🫣🫣🫣

My thought is that those recommendations are targeted at decreasing costs for car makers that offer extended/lifetime service contracts. If a maker only has to pay for 10 oil changes in the 100,000 mile service plan it's cheaper than 20 oil changes. And zero transmission fluid changes is zero $ charged to a service plan. No lube fittings in the chassis means no lube charges to the service plan. It adds up. Just my WAG anyway.

 

[Jeep Junkie]

My thought is that those recommendations are targeted at decreasing costs for car makers that offer extended/lifetime service contracts. If a maker only has to pay for 10 oil changes in the 100,000 mile service plan it's cheaper than 20 oil changes. And zero transmission fluid changes is zero $ charged to a service plan. No lube fittings in the chassis means no lube charges to the service plan. It adds up. Just my WAG anyway.

So that means that the 0w20 recommendation is also due to financial reasons, CAFE factor, No?

 

[swampflyer]

Just checked with amw and they are using Mobile 1, 5w20 in the hemi. I'm still trying to decide. 5w30 I'm leaning towards but what brand is still in the air.

 

[Jeep Junkie]

Just checked with amw and they are using Mobile 1, 5w20 in the hemi. I'm still trying to decide. 5w30 I'm leaning towards but what brand is still in the air.

PUP Of course

 

[Ratbert]

Bro, I'm running the oil meant for the turbocharged V8 Mercedes G Wagon, Pennzoil Platinum Euro 0W-40. In a couple of weeks I will report how things went

So you're intentionally moving your Hersey number to the right on the Stribek curve, most likely to the point where you're just increasing friction with no wear benefit?

I have no idea why you're mentioning the oil that happens to be used by a specific Mercedes. Are you thinking your v6 is somehow engineered with the same characteristics?

 

[Sidewalk]

Seeing people complain about destroying cams with various oil options isn't convincing me that running thicker oil is going to be of any benefit.

 

[Jeep Junkie]

So you're intentionally moving your Hersey number to the right on the Stribek curve, most likely to the point where you're just increasing friction with no wear benefit?

I have no idea why you're mentioning the oil that happens to be used by a specific Mercedes. Are you thinking your v6 is somehow engineered with the same characteristics?

Because no oil is too thick, too thin yes but not too thick, as long one uses the appropriate winter rating. Only downside of thick oil is bad mpg and loss of power which even that didn't happen in my case. My Jeep still feels like a rocket ship.

 

[Jeep Junkie]

Also, this cold flow of oil is also misunderstood. Oil in the engine doesn't flow by gravity, the system is pressurized, oil is under constant pressure. 0w20 or 5w30 or 0w40 or 20w60, as long oil is pumpable(Has the proper winter rating), oil pump will shoot it whereever it needs to be.

 

[Jeep Junkie]

Also, there are some things famous people can't say in public. For example, stopping people from making a right turn on red(when it is safe), is a stupid law. In private I would tell you to go for the turn when it is safe. But would I say that on a public platform if I was a famous person? Hell no! So that's why famous Youtubers like Engineering Explained tell you to follow your owners manual. Even Project Farm, after proving that thin oils cause more wear, dropped the "Follow your owners manual" BS. In private I bet he would tell you to stay away from 0w20 garbage.

 

[Mike_Hawk]

Anyone have any luck with peanut oil?

 

[c20040215]

If I get a dollar every time someone post on oil weight threads...

 

[grimmjeeper]

Anyone have any luck with peanut oil?

Not as much as I wanted.

 

[Sftdyna0326$]

So that means that the 0w20 recommendation is also due to financial reasons, CAFE factor, No?

Well now that there taming the cafe standards maybe things like piss weight oils and MDS in our jeep V8's will change.

 

[Odyssey USA]

My personal opinion based on the info I can find is that I'd be modest with any change to the operating temp viscosity, the last number, and I wouldn't change the first number from what's recommended. Yeah, the engine initially came recommending 5w-30 but with the PUG variant, they did move to what they described as "low tension" rings. They were likely low tension before relative to what us old schoolers were used to but they went lower, at minimum. As to the rod bearing clearance and main bearings, same exact clearances as when the engine came out compared to the PUG. So it is feasible that ring pack oil control could be a factor. Stick to the cold flow viscosity they recommend as that will help get the oil to the typically concerning valvetrain. If you think that going up on the first number like 5W will help, it'll only "cling" a little better by minutes. The oil needs to get to parts quickly under cold start operating conditions. It's the most important number to be careful about deviating from.

The second, at full op temp viscosity, number could be a concern if the viscosity is too high when considering ring tension. I personally think it's a waste of time to go past 30 even though a cold 0W rated oil is thicker than a full op temp viscosity rating of 40. Odds are they struck a balance between oil control when cold and fully warmed up but with an eye towards efficiency so a 0w-30 may be ok and my dealership gave the ok using that in warm weather fwiw. No science there.

That said, the only way to know what cuts wear would be testing by companies that test above 5 microns for a thorough idea of what wear looks like and try, in my opinion, 0w-20 vs 0w-30 in the same line of oil to try to take out additives as a factor. They tend to be close. Don't hold me to it but if you find the 0w-20 works better for wear, you might try the M1 Truck & SUV 0w-20 and test that too as I think it may have at least some of the better base oils like the M1 ESP line. Also, I don't believe Blackstone goes over 5 micros on particle detection but I'd ask in case they offer that. You may have to pay extra to get those results with them or other companies.

I don't know for sure but in my experience in many things, less is more if you're going to make changes to see a trend systematically.

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