Red Line 5w-20 11,000 miles Chevy Suburban 5.3L

[shanneba]

The 40 weight rating is at a specific temp, 100C for the cSt viscosity and 212 F for the SUS viscosity.
The Red Line 5w-40 at 165 F would be as thick as a 50+ weight SAE oil at 100C (212F). That same 50 weight oil would be even thicker at the same 165 F.
All oil thickens as the temperature decreases.

 

[JohnBrowning]

shanneba, Oil do not thicken with heat!!!!LMAO!!! When was the last time you changed hot oil and it came out like molases? Oil thins as it heats put a bottle of 20W50 in your freezer and one bottle in a pan of boiling water. Now this is not even close to test conditions but it will do. I assure you that after a few hours in each environment you will see a huge difference in how these too otherwise identical samples pour. The hot oil will pour much faster then the cold stuff. If you leave that 20W50 in the freezer over night it will pour like mable syrup taken right from the refrigerator.

 

[427Z06]

Quote:

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shanneba, Oil do not thicken with heat!!!!LMAO!!! When was the last time you changed hot oil and it came out like molases? Oil thins as it heats put a bottle of 20W50 in your freezer and one bottle in a pan of boiling water. Now this is not even close to test conditions but it will do. I assure you that after a few hours in each environment you will see a huge difference in how these too otherwise identical samples pour. The hot oil will pour much faster then the cold stuff. If you leave that 20W50 in the freezer over night it will pour like mable syrup taken right from the refrigerator.

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JB, read shanneba's post again. He has it right.

 

[427Z06]

For RinconVTR, this chart shows how oils are graded as far as viscosity:

 

[wwillson]

I always ran 15w-40 year-around until I found a viscosity calculator. Once I realized just how this 40wt oil is at 165F I switched to a 20wt oil.

Wayne

 

[Rand]

The sump might be 165 but how do you know how high localized temperatures are?

 

[427Z06]

Quote:

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The sump might be 165 but how do you know how high localized temperatures are?

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Localized temps may or may not be higher relative to the sump, but the sump has always been the accepted reference temperature. You don't change where you measure the oil temperature just because you use a different viscosity oil. Measuring at the oil filter, is, for all practical purposes, like measuring at the sump.

 

[buster]

wwillson, are you still running RL?