Help me understand CCS viscosity versus API grade

[matt88-8]

Hey all. Im new here, long story short, I was looking at reducing the amount of oils I buy, and was looking at the difference between the 5w30 and 0w20 that I use.

Am I missing something, or is the 5w30 CCS viscosity not lower than the 0w20? Why is that?

Thanks in advance, I'm not really sure how to Google this question lol.

 

[dnewton3]

Well, for one thing, they are not directly comparable because they are tested at different temps. (-30 ... -35 ... -40)

 

[matt88-8]

Well, for one thing, they are not directly comparable because they are tested at different temps. (-30 ... -35 ... -40)

Is that done so its difficult to compare? Seems silly to test one at -35 and one at -30.. both are tested hot at 100c..

 

[Plumb Bob]

Is that done so its difficult to compare? Seems silly to test one at -35 and one at -30.. both are tested hot at 100c..

One passes the test at -35 F, the other doesn't.

Thread 'SAE J300 Viscosity Grades'

Nov 11, 2024

When you buy a quantity of oil, probably the first thing you look for is the SAE grade. But what do these numbers represent; what do they mean? In this post we will explore the fundamentals of SAE J300, which is the standard under which these grades are defined and often a point of considerable confusion.

At its simplest, a multigrade oil is identified by two numbers:
1. The Winter grade, this is the number BEFORE the W
2. The SAE grade, this is the number AFTER the W

These numbers are not related.

Both numbers (grades) represent clearly defined ranges, outlined as...

• OVERKILL
• Replies: 55
• Forum: Passenger Car Motor Oil (PCMO) - Gasoline Vehicles

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[RallyXaDSM]

Is that done so its difficult to compare? Seems silly to test one at -35 and one at -30.. both are tested hot at 100c..

Either the oil is below 6200 cP at -35 Celsius or it isn't. That determines if it is a 0w or not and the same for the ascending grades above it

 

[matt88-8]

Okay. I get it now. The winter grade isnt a set temperature, but rather a maximum thickness at each temp level.

That makes more sense. So simply the 5w30 isnt below 6,200@-35 and therefore must be a 5w.
It definitely makes sense now.
I was just trying to see how much thicker the 5w30 i use was in winter than the 0w20. Basically I didn't want to start a "what grade should I use" thread, as i can only *imagine* how that goes

Thank you guys for teaching me and providing those charts.

 

[M405]

I just posted on the forum and this question is related to what I'm trying to find out.

Does this mean a 0W oil will have better low temp crank low temp pumpability than a 5W oil universally regardless of brand or acea/manufacturer spec?

Also I assumed that the relationship between viscosity and low temperature is not linear. Does this mean that it is possible to have two different oils which are closer in viscosity at say minus 10 degrees Celsius than say minus 30 degrees Celsius?

 

[matt88-8]

I just posted on the forum and this question is related to what I'm trying to find out.

Does this mean a 0W oil will have better low temp crank low temp pumpability than a 5W oil universally regardless of brand or acea/manufacturer spec?

Also I assumed that the relationship between viscosity and low temperature is not linear. Does this mean that it is possible to have two different oils which are closer in viscosity at say minus 10 degrees Celsius than say minus 30 degrees Celsius?

The link Plumb Bob posted said that oil MUST be marketed as the lowest grade it meets. So in theory, any 0w should be thinner at -35 than any 5w.
(That's my understanding. Thoughts?)

But, I haven't yet seen if there is any way to compare them at the same temp. IE its -20 here tonight, are the 0w and 5w i have in my vehicles side by side in the driveway close?

 

[Titan]

I just posted on the forum and this question is related to what I'm trying to find out.

Does this mean a 0W oil will have better low temp crank low temp pumpability than a 5W oil universally regardless of brand or acea/manufacturer spec?

Also I assumed that the relationship between viscosity and low temperature is not linear. Does this mean that it is possible to have two different oils which are closer in viscosity at say minus 10 degrees Celsius than say minus 30 degrees Celsius?

It's possible to have a 0w-30 oil that is thicker than a 5w-30 weight oil at temperatures above minus 30 F. Mobil 1 ESP 0w-30 is thicker than MOST 5w-30's at 100 C and even up to 150 C (HTHS temperature). It's not as simple as so many seem to think: that 5w-30 is inherently thicker than 0w-30...there are "relatively thin" 5w-30's that fall within the lower area of the 30 weight viscosity range and "relatively thick" 0w-30's that are near the top of the 30 weight range. Same holds true for 5w-20 vs 0w-20....there are 0w-20's that are thicker than some 5w-20's at operating temp or HTHS temp, but obviously thinner at temps below minus 35...when the 5w-20 stops being pumpable while the 0w-20 is still pumpable.

 

[Titan]

The link Plumb Bob posted said that oil MUST be marketed as the lowest grade it meets. So in theory, any 0w should be thinner at -35 than any 5w.
(That's my understanding. Thoughts?)

But, I haven't yet seen if there is any way to compare them at the same temp. IE its -20 here tonight, are the 0w and 5w i have in my vehicles side by side in the driveway close?

According to the 2015 chart above, 0w-XX oil is pumpable all the way down to minus 40 F. 5w-XX oil is pumpable all the way down to minus 35 F. Where the viscosity of each oil lands at minus 20 F is not defined by the Xw-XX ratings. It's certainly possible a 0w-XX oil could be thicker at minus 20 F than a 5w-XX oil.

 

[M405]

Regarding the original question from the OP I'm surprised nobody has made a graph for the CCS and MRV of various 0W and 5W oils. This would help to compare the different oils. Perhaps there's a secret formula somebody has, to enable somebody to compare viscosity, with the data taken from the tests conducted at different temperatures.

 

[Rand]

Yes you are missing something.

Regarding the original question from the OP I'm surprised nobody has made a graph for the CCS and MRV of various 0W and 5W oils. This would help to compare the different oils. Perhaps there's a secret formula somebody has, to enable somebody to compare viscosity, with the data taken from the tests conducted at different temperatures.

There is one but it is not accurate at low temps. So it would be less than useful for that purpose.
.. now if you want to know which oil is thicker at 20C for some reason...

 

[Plumb Bob]

The link Plumb Bob posted said that oil MUST be marketed as the lowest grade it meets. So in theory, any 0w should be thinner at -35 than any 5w.

0W-60 is a LOT thicker at -35 F than 5W-30 is. Yet, it cranks and pumps, whereas the 5W doesn't necessarily do so.
Re-read the @OVERKILL post.

 

[kschachn]

Regarding the original question from the OP I'm surprised nobody has made a graph for the CCS and MRV of various 0W and 5W oils. This would help to compare the different oils. Perhaps there's a secret formula somebody has, to enable somebody to compare viscosity, with the data taken from the tests conducted at different temperatures.

That’s because it isn’t really important. It’s about pumpability, whether the oil will pump or not. If it pumps it will flow.

 

[M405]

0W-60 is a LOT thicker at -35 F than 5W-30 is. Yet, it cranks and pumps, whereas the 5W doesn't necessarily do so.
Re-read the @OVERKILL post.

This seems counterintuitive to a layperson. One would think a thicker oil flows less at -35 than a thinner oil. I understand if the 0W60 is thicker than the 5W30 at room temp then at colder temperatures (-35) it becomes less viscous hence the naming classification of course.

So the message is that lower viscosity at -35 does not necessarily mean higher flow is this correct?

 

[kschachn]

This seems counterintuitive to a layperson. One would think a thicker oil flows less at -35 than a thinner oil. I understand if the 0W60 is thicker than the 5W30 at room temp then at colder temperatures (-35) it becomes less viscous hence the naming classification of course.

So the message is that lower viscosity at -35 does not necessarily mean higher flow is this correct?

The only flow that really matters is between the sump and the pump pickup tube. If it makes it there then it will flow in the engine. The important flow is represented by the oil’s winter rating.