Is 0w30 a better choice than 5w20 ?

[Seth]

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Seth, you probably know this, but don't be fooled by the "0" in 0w30 vs the "5" in 5w20 - the 5w20 is going to be thinner at temps across the board (low and high).

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Here's a quote from motor oil bible

"Results from the Cold Crank Simulator (CCS) and Mini-Rotary Viscometer (MRV) tests are used to
determine the oil's "W" grade. The better the engine "startability" of the oil at low temperature, the lower
the W classification. Each W grade must meet certain "startability" requirements at a specified
temperature.
For instance, a 0W grade oil must have a maximum CCS centipoise (cP) value of 3250 @ -30 degrees
C as well as a maximum MRV cP of 60,000 @ -40 degrees C. A 5W grade oil must have a maximum
CCS cP value of 3500 @ -25 degree C and a maximum MRV cP of 60,000 @ -30 degrees C. The
lower the cP value for both specifications, the better.
Notice that the 0W grade oil is tested at a lower temperature on both tests AND must still have a lower
CCS cP value than a 5W oil which is tested at a higher temperature. As a result, a 0w30 will allow your
vehicle to start easier on a cold morning than a 5w30 will. Likewise, a 5w30 oil will pump easier in cold
temperatures than a 10w30 oil will."

 

[AEHaas]

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No it's viscosity at 75 F and 212 F !! I' write it better.


------thickness at 75 F -----------at 212 F

Straight 30________250 _______________10
10w-30 ____________100________________10
0w-30 _____________40_________________10 cT (centiStokes)

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This data was made up to illustrate the principal of a multi-grade oil. If you read the original chapters that were written for the Novice one would understand the numbers better.

aehaas

 

[Seth]

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Seth
A 0w30 will always be a 30 weight and a 5w-20 will always be a 20 weight, across the range of temperatures.

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Not sure about the "across the range of temperatures" part. I think you refer to at 100 deg celsius. Anyways, my point was that 0w30 has advantages to prevent startup wear and has film strength to accommodate larger contaminants when it gets real hot. Not to mention other things I mentioned in original post once operating temps have reached. Only downside I see is fuel mileage which is probably not discernible. Tech2000 0w30 is giving me good mileage like 5w20 does. I do agree that 0w20 is a good idea in winter where as 0w30 (not the thicker varieties like GC) are good for rest of the year where 5w20 is specd (in my case mitsu makes an allowance for 10w30 when temps > 100F otherwise 5w20 is recommended for low fuel consumption)

 

[ConfederateTyrant]

Seth,
What I am trying to get at is that an oil's viscosity at X temperature is X cSt.

This is only used as a way of explaining, and may not be true for many oils. Say for instance, 0w30 has a cSt of 10.5 at 100 C and a 5w-20 has a cSt of 9 at 100 C. In the event that the 5w-20 only gets up to 95 C, then the cSt could be 11 or somewhere around there, which is where my 2nd paragraph comes from.

So while the cSt rating for a 20 weight at 95 C is thicker than the cSt at 100 C, but at each specific temperature, it is still a 20 weight. Same concept for the 30 weight.

That's what I have been able to gather, if someone can explain more, or correct any misinterpretations, provide some input.

 

[Seth]

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So while the cSt rating for a 20 weight at 95 C is thicker than the cSt at 100 C, but at each specific temperature, it is still a 20 weight. Same concept for the 30 weight.

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Sounds right...

OT.. still flying confederate flags down south? Just kidding... love peach state (Athens, Atlanta)...

 

[ConfederateTyrant]

Glad to see I managed to piece together the concept of multi-viscosity oils.

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OT.. still flying confederate flags down south? Just kidding... love peach state (Athens, Atlanta)...

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some of us are, including the state of Georgia, since the current flag is a confederate flag. I don't get why everyone b****ed about one but not the other...

 

[pp_rp]

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No it's viscosity at 75 F and 212 F !! I' write it better.


------thickness at 75 F -----------at 212 F

Straight 30________250 _______________10
10w-30 ____________100________________10
0w-30 _____________40_________________10 cT (centiStokes)

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This data was made up to illustrate the principal of a multi-grade oil. If you read the original chapters that were written for the Novice one would understand the numbers better.

aehaas

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I agree with Dr. Haas. I live in MN. and it gets in the neg. temps. When I have used thinner oil my engine turns over easier and makes alot less noise when it's warming up. If you ever heard a -30F engine just start and and idle it makes alot of noise. 0w-20 is what i will be using this winter.