Motor Oil Explain / Discussion

To further muddle things….
Viscosity Grades (SAE Classification)
• Represented by numbers like 5W-30, 10W-40, etc.
• The first number with “W” (winter) indicates cold temperature flow; lower means better cold start performance.
• The second number indicates viscosity at high operating temperatures; higher means thicker oil that maintains protection when hot.
• Single-grade oils have a fixed viscosity suitable for either cold or hot conditions.
• Multi-grade oils, like 5W-30, perform well across a wide temperature range due to viscosity modifiers.
Common Engine Oil Grades Examples
• 5W-30: Good cold start and moderate high-temp protection.
• 10W-40: Slightly thicker at operating temperature, good for warmer climates.
• 15W-40, 20W-50: Thicker oils often used in older engines or high-heat conditions.
In summary, engine oil grades indicate how the oil performs under different temperature conditions and its suitability for various engine types and emission standards. Multi-grade oils like 5W-30 are most common for modern engines due to their versa
 
1st Vette said:
To further muddle things….
Viscosity Grades (SAE Classification)
• Represented by numbers like 5W-30, 10W-40, etc.
• The first number with “W” (winter) indicates cold temperature flow; lower means better cold start performance.
• The second number indicates viscosity at high operating temperatures; higher means thicker oil that maintains protection when hot.
• Single-grade oils have a fixed viscosity suitable for either cold or hot conditions.
• Multi-grade oils, like 5W-30, perform well across a wide temperature range due to viscosity modifiers.
Common Engine Oil Grades Examples
• 5W-30: Good cold start and moderate high-temp protection.
• 10W-40: Slightly thicker at operating temperature, good for warmer climates.
• 15W-40, 20W-50: Thicker oils often used in older engines or high-heat conditions.
In summary, engine oil grades indicate how the oil performs under different temperature conditions and its suitability for various engine types and emission standards. Multi-grade oils like 5W-30 are most common for modern engines due to their versa
Click to expand...
That's exactly how I now understand it. Though I knew the w stood for winter I also thought it meant it acted like a 5 in the cold, but it's only relative to other w numbers.
 
Murray20c8 said:
No, not true. as you could see in brainiacs video demo. It flows a lot slower and thicker than a 5 viscosity oil.
Click to expand...
What I do know is that years ago when I did an oil change on my beaters what went in was whatever was in the various jugs in my garage. More of a blend than single malt so to speak. Never had any issues, lol . It’s seemingly a more complicated topic than one would think these days. I will continue to use the recommended 0w-40 supercar oil and not worry about it.
 
1st Vette said:
What I do know is that years ago when I did an oil change on my beaters what went in was whatever was in the various jugs in my garage. More of a blend than single malt so to speak. Never had any issues, lol . It’s seemingly a more complicated topic than one would think these days.
Click to expand...
A friend takes the old synthetic oil from his car and uses it in his tractors. LOL.
If not for the warranty, I'd use 5w30 in my car and likely will when the warranty is over. Good oil is good oil IMO.
 
This point from the search relates to GM’s solution to the LT6 engine problem.

.The second number indicates viscosity at high operating temperatures; higher means thicker oil that maintains protection when hot.

They are now recommending a higher viscosity oil . Kind of a lame solution if you think about it but they claim it will reduce failures. I wouldn’t be too impressed if I owned one.
 
Mescal with a slice of lime……
Rruuff Day said:
So based on the above, and just to add to a really interesting thread (:Yawn:), what should you use when it's winter in Florida or Mexico where it's 25 degrees (80 F) in the winter....
Click to expand...
 
Murray20c8 said:
I understood the w is for winter, so then the 5 doesn't mean it acts like a 5 weight when cold? It's just a reference to other w's?
It's still misleading. He's comparing cold oil to warm oil to try and prove that the w is doing something. He should have compared cold 5w30 to a cold 15w30. His test shows nothing.
Click to expand...
Yes, it behaves like a straight 5 weight when BOTH are cold. Not like a hot, or even room temperature 5 weight. A straight 5 wt gets thick when cold, too. Just not as thick as a straight 10, or 20, or 30 weight does when cold.

A agree with your comment on the video.
 
Seeing how the vast majority of C8 Corvette owners know what oil is recommended by the manufacturer and their engineers I have the feeling it’s probably about time we put this one to sleep. Further specific inquiries regarding the LT2 engine maintenance requirements can again be posted in the C8 forum. Thanks.
 
Last edited:
cdnz said:
Think twice before rumning E85 or at least do your oil changes often? For most of us Canadian, this is an non issue because we can't get E85.
Click to expand...

Considering that GM states that the required/recommended fuel for the C8 is 93 octane or minimum 91 octane Top Tier fuel it should be a moot point……..
 
1st Vette said:
Considering that GM states that the required/recommended fuel for the C8 is 93 octane or minimum 91 octane Top Tier fuel it should be a moot point……..
Click to expand...
My take was be cautious if you run E85. My understanding is not only using ethanol to rise your octane. So if you run 93/94, it doesn't have more ethanol than those other lower grades.
Go fuel up from a station that supply for marine use which has no ethanol. lol.

per AI
"No, 87 octane gasoline does not necessarily have less ethanol than 93 octane. In many regions, both 87 and 93 octane gasoline contain up to 10% ethanol, as mandated by law or standard practice"
 
Last edited:

cdnz said:
My take was be cautious if you run E85. My understanding is not only using ethanol to rise your octane. So if you run 93/94, it doesn't have more ethanol than those other lower grades.
Go fuel up from a station that supply for marine use which has no ethanol. lol.

per AI
"No, 87 octane gasoline does not necessarily have less ethanol than 93 octane. In many regions, both 87 and 93 octane gasoline contain up to 10% ethanol, as mandated by law or standard practice"
Click to expand...
Sure, it all has alcohol . the important thing is 91 or 93 which is also Top Tier. I burn a mix of 100 low lead and regular in my Bonneville for the lead component but that engine is 60 Years old and likes it . But I had to replace the fuel pump because the ethanol ate the diaphragm. Don't burn E85 in your C8 unless you want issues .....
 

Users who are viewing this thread

Total: 1 (members: 0, guests: 1)
Back
Top