Synthetic oil differences

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I don't think engines are ever designed for a certain weight oil. Too many variables.
Actually, sometimes they are. On the newest version of the Pentastar, for example, they tightened the diameter of oil journals in the head. I am told they were going with 0w20 from the outset and they did all of the development and durability testing with 0w20.
 
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Actually, sometimes they are. On the newest version of the Pentastar, for example, they tightened the diameter of oil journals in the head. I am told they were going with 0w20 from the outset and they did all of the development and durability testing with 0w20.
Yes an engine can incorporate design changes that will help it tolerate thinner oils but none of those changes will preclude the use of thicker ones.
 

OVERKILL

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So they made the passages more narrow so it can tolerate thinner oils? Please help me make sense of that.
Tighter/wider bearings are indeed more tolerant of thinner lubes. That was the risk with going below 0w-16 and why Honda had to do the bottom-end redesign on engines that were spec'ing 0w-12, the bearings weren't sufficiently wide to allow the use of oil that thin (provide adequate MOFT).
 
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Tighter/wider bearings are indeed more tolerant of thinner lubes. That was the risk with going below 0w-16 and why Honda had to do the bottom-end redesign on engines that were spec'ing 0w-12, the bearings weren't sufficiently wide to allow the use of oil that thin (provide adequate MOFT).
I was talking passage or oil journal width/diameter, not bearing width. Maybe I didn't state it clearly originally. The newer gen Pentastar has smaller diameter oil journals. They designed this engine with 0w20 in mind.
 

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I was talking passage or oil journal width/diameter, not bearing width. Maybe I didn't state it clearly originally. The newer gen Pentastar has smaller diameter oil journals. They designed this engine with 0w20 in mind.
Yes, when you said journals, I assumed you meant bearing journals in the heads.
 
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I'm new to the forum, but I have read the homepage of scientific papers with interest, and I was pretty impressed. I run Redline 5W20 with about 6k change intervals. I have no soapbox reason, but it seems to dance well in my LS3 engine after 55k of ownership. 🤷‍♂️
 
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Actually, sometimes they are. On the newest version of the Pentastar, for example, they tightened the diameter of oil journals in the head. I am told they were going with 0w20 from the outset and they did all of the development and durability testing with 0w20.
Yet my 2022 RAM 1500 3.6 "recommends" 5W20 OR 5W30 "if" 5W20 isn't available.
 
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Yet my 2022 RAM 1500 3.6 "recommends" 5W20 OR 5W30 "if" 5W20 isn't available.
Your owner's manual does not say that.

From page 473 of your 2022 RAM Owners Manual: "We recommend using Mopar 0w20 Full Synthetic Engine Oil which meets the requirements of the manufacturer material standard MS6395. Equivalent SAE 0w20 engine oil can be used, but must have the API Starburst trademark."

You may have misinterpreted this on page 409, which is not the recommendation page, but rather describes the API symbols.

"American Petroleum Institute (API) Approved Engine Oil These symbols mean that the oil has been certified by the API. The manufacturer only recommends API trademark oils. The API Starburst trademark certifies 0W-20, 5w20, and 5W-30 engine oils. The API Donut trademark certifies 0W-40 and 5W-40 engine oil."

Page 473 is where the actual recommendation is for your engine as well as the 5.7. 0w20 is the only oil mentioned. In fact, from what I've seen, everywhere else in the world where this version of the Pentastar is sold, the manuals recommend only 0w20.
 
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Your owner's manual does not say that.

From page 473 of your 2022 RAM Owners Manual: "We recommend using Mopar 0w20 Full Synthetic Engine Oil which meets the requirements of the manufacturer material standard MS6395. Equivalent SAE 0w20 engine oil can be used, but must have the API Starburst trademark."

You may have misinterpreted this on page 409, which is not the recommendation page, but rather describes the API symbols.

"American Petroleum Institute (API) Approved Engine Oil These symbols mean that the oil has been certified by the API. The manufacturer only recommends API trademark oils. The API Starburst trademark certifies 0W-20, 5w20, and 5W-30 engine oils. The API Donut trademark certifies 0W-40 and 5W-40 engine oil."

Page 473 is where the actual recommendation is for your engine as well as the 5.7. 0w20 is the only oil mentioned. In fact, from what I've seen, everywhere else in the world where this version of the Pentastar is sold, the manuals recommend only 0w20.
"My" 2022 RAM 1500 "CLASSIC" owners manual says this from page 341.
"We recommend using Mopar® SAE 5W-20 Full Synthetic Engine Oil which
meets the requirements of the manufacturer Material Standard MS-6395.
Equivalent full synthetic SAE 5W-20 engine oil can be used but must have the
API Starburst trademark Ú page 286.
Mopar® SAE 5W-30 engine oil approved to the manufacturer Material
Standard MS-6395 may be used when SAE 5W-20 engine oil meeting
MS-6395 is not available."
There "2" 2022 RAM 1500 owners manuals. One is for the RAM 1500. The other one, RAM 1500 CLASSIC. Mine Why??? I don't know. I not only have it in hand but if you google "RAM 1500 CLASSIC Owners Manual" you will see same.

What is really weird. 2022 RAM 1500 owners manual says on page 477 the 3.6 take 5qts w/filter. Yet 2022 RAM 1500 "CLASSIC" Owners manaul says also on page 341 the 3.6 takes 6qts w/filter. Mine does in fact take 6qts w/filter to be FULL on the dipstick. With 5qts w/filter it shows 1qt LOW. So if you can figure out what is what, please do.
 
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