5W 30 versus 0W 20

[Jeep Junkie]

In the title of the thread it says 5w-30 vice 0w-20. Did you mean "vs." ??
If so, then this is the thread for you: a Little light reading about this subject.

https://www.jlwranglerforums.com/forum/threads/ditch-the-0w-20-before-its-too-late.124368/

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[Jeep Junkie]

A trusted mechanic told me that the change to 0W-20 was not just made to improve fuel economy but also to reduce cylinder scoring due to tighter piston tolerances in the newer engines.

So what does that mean, 0w20 is good for us or bad for us?

 

[Jeep Junkie]

OP, if you have a lot of money and if you are interested in an oil that does not lose viscosity with use, but gains viscosity with use, then I have an oil for you. In technical language, it does not shear.

 

[DaltonGang]

Awesome, let's help that thread grow even more

I just want everyone to know what the EPA and the complacent auto manufacturers are up to. I know the 5w-30 oil made a dramatic difference in the way my Jeep sounds and feels. I dont give a rats patooty what the manual says, or what some theoretical engineers say 0w-20 is designed to do.

 

[Jeep Junkie]

I just want everyone to know what the EPA and the complacent auto manufacturers are up to. I know the 5w-30 oil made a dramatic difference in the way my Jeep sounds and feels. I dont give a rats patooty what the manual says, or what some theoretical engineers say 0w-20 is designed to do.

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.

 

[Jeep Junkie]

People who push their 0W-20 hard and long, end up with something like 5W-16.

 

[Jeep Junkie]

Guys, hurry up! It comes in a nice box
5 jugs for less than one oil change at stupid Jiffy Lube.

 

[Odyssey USA]

A trusted mechanic told me that the change to 0W-20 was not just made to improve fuel economy but also to reduce cylinder scoring due to tighter piston tolerances in the newer engines.

All motor oil thins as it heats up. If you’re uncomfortable, stick with 0w but up the second number.

The piston to cyl wall clearance is set with the block being machined. The piston expands faster than the cylinder and this is typically accounted for in the machining. That said, you go wide open throttle on a fully cold engine…it’s possible to get the rapidly expanding top ring area wedged because the skirt hasn’t heated enough to cut down on piston rock. Scoring could be from debris stuck in the rings. That could be from lack of oil changes for the the operating conditions. Burnishing (no or minimal oil retaining crosshatch) of the cylinder walls can be from lack of piston ring pack rotation due to carbon buildup, the cylinder being out of round, or excess fuel in the combustion process washing oil from the walls.

The easiest way to compare a 0w and a 5w? About 9°F. 0w will flow at well below freezing about 9° lower than a typical 5w. If you pay enough, you can source a 5w that will flow better than typical 0w’s.

And regarding wear, only testing the oil with requested sub 5 micron testing included will give unbiased insight. Generally though, in competitive drag racing we didn’t want oil windage which can kill high rpm power. We ran the oil as thin as we could get away with because the net gain was positive. We tore the engine down every season. If the bearings looked good, we might go tighter if the crank was not junk. A passenger vehicle, you would want more margin for the varying operating conditions. The manufacturers are cutting it close.

The 3.6 with the same specs and same industry accepted oil viscosity rating system was first introduced recommending 5w-30. I’ve verified the bearing clearance specs are the same today. The first number is the most important to be careful with. The second number, you’re fine until maybe over 40. 0w at 40°C is thicker than the 40 rating which is measured at 100°C.

Some of this is addressing your post but I’m also addressing the overall oil topic.

 

[Odyssey USA]

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.

You’re buying HPL man. Just get the 0w-30 or even better, the 40.

 

[Jeep Junkie]

You’re buying HPL man. Just get the 0w-30 or even better, the 40.

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.

 

[Upnarms]

I ran 0w20 to 65k miles. Rocker arm failure at 57k. New cam and rocker arms. I started running 5w30 last oil change. Much quieter on start up. Dont notice any other differences yet.

 

[iklo]

In the BMW La-la land we only use the officially aproved oil. Could be various viscosities but must carry something like LL-01 on the jug. People bitch about brands and endlessly debate 0W-40 vs 5W-30, but all stare at awe on the approval label.

 

[Odyssey USA]

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.

Found that. I’m not sure if the Premium Plus 0w-40 is gonna trend the same but I’m not going past 5k with it. I’ll let you know if I blow it up. lol

 

[Jeep Junkie]

Found that. I’m not sure if the Premium Plus 0w-40 is gonna trend the same but I’m not going past 5k with it. I’ll let you know if I blow it up. lol

No, Premium Plus will shear. It is the No VII and Super Car that are weird.

 

[Jeep Junkie]

Found that. I’m not sure if the Premium Plus 0w-40 is gonna trend the same but I’m not going past 5k with it. I’ll let you know if I blow it up. lol

Don't yell at me but I bought a 12 quart case. I am just nervous about using it. It starts at 8.9, not sure where it will end after 5000 miles 🫣
It has a pour point of -81 degrees F That's pure PAO for sure

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