ASTM D5293 (CCS) vs. ASTM D4684 (MRV)

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As I do lack deeper understanding of both ASTM D5293 and ASTM D4684 I'd highly appreciate
some help.
Apparently ASTM D5293 is for CCS viscosity while ASTM D4684 is for MRV/low temp. pumping
viscosity. I came across a seemingly odd observation while comparing the datasheets of both
Ravenol REP 5W-30 and VMP 5W-30. To me they don't correlate the way I had expected. When
both are similar base oil composition (which is just an assumption), similar kinetic viscosity and
exact same pourpoint, shouldn't the oil with the lower CSS also exhibit the lower MRV? If it isn't
the case, should I conclude base oil compositions aren't the same? Different amount of VII? :unsure:

Ravenol REP 5W-30:

CCS Viscosity at -30 °C4301mPa*sASTM D5293
Low Temp. Pumping viscosity (MRV) at -35 °C14.870mPa*sASTM D4684


Ravenol VMP 5W-30:

CCS Viscosity at -30 °C4740mPa*sASTM D5293
Low Temp. Pumping viscosity (MRV) at -35 °C12.000mPa*sASTM D4684


That said, Ravenol RUP 5W-40 acts as expected from a thicker version of REP (higher PP and KV40) .....

CCS Viscosity at -30 °C4510mPa*sASTM D5293
Low Temp. Pumping viscosity (MRV) at -35 °C21.300mPa*sASTM D4684


..... while it's still lower CCS viscosity compared to VMP 5W-30 though.

Hope I made my little dilemma sufficiently clear. Again I'd highly appreciate administrable answers.
Thanks in advance! (y)


for reference:


 
MRV has a lot variance in it, which may explain why the limit on it is so high. 12,000 is also a pretty round figure ;)

MRV was developed as a test to replace Pour Point, which had proven to be wildly inaccurate in predicting the oil's ability to actually be pumped. Because it's a yield stress test, wax crystal formation in non-PAO bases is a big contributor to some of the high MRV numbers we see from some blenders. PPD's do their job, but it's not as linear a progression as with PAO.

CCS on the other hand is a shear test (apparent viscosity) which is about drag, not yield. Even a non-wax containing base like PAO thickens when cold and if the blend is too heavy, it can fail to pass the CCS test even if it does extremely well on MRV (because it doesn't gel).

What I get from those numbers, if we assume they are accurate and that the deviation isn't within the margin of error for MRV (I don't know the limit off-hand) is that VMP may have a slightly heavier PAO base oil blend while REP may have a splash of Group III, AN, POE, something that changes how it performs in the MRV test. That's my guess anyways.
 
.
Thanks for your explanation. I was guessing it's something related to base
oil blend, PPD and VII used. There's still some mystery remaining about it.
.
 
CCS and MRV measure different properties.

Imagine a bowl of Jell-O. If you tilt the bowl the Jell-O does not pour, behaving like a solid. Now take a spoon and scoop a hole in the Jell-O. The hole remains and the Jell-O does not flow back in to refill the hole. This is the property measured by the MRV test, that is, the gelling tendency of the oil at low temperatures. In an engine we need the oil to flow back into the hole sucked out by the oil pump or else the pump will suck air and cause oil starvation.

Now take the same bowl of Jell-O and stir it with a spoon. What appeared to be a solid now moves freely under the shearing action of the spoon, no longer behaving like a solid. This is the property measured by the CCS test, where the oil is stirred by a rotor during the cooling process. By eliminating the gelling tendency of the oil, usually caused by wax, we measure the viscosity of the oil under pumping conditions.

Because the two tests measure different properties of an oil, they do not necessarily correlate. Both are needed to predict the performance of an oil in an engine under cold temperatures.
 
Thank you Tom, I'm glad you chimed in. (y)

Would the same explanation apply to pourpoint? Since the PP is -60°C for two of
the oils I mentioned, wouldn't they still be rather viscous but still liquid at -35°C?

Imagine a bowl of Jell-O. If you tilt the bowl the Jell-O does not pour, behaving like a solid. Now take a spoon and scoop a hole in the Jell-O. The hole remains and the Jell-O does not flow back in to refill the hole. This is the property measured by the MRV test, that is, the gelling tendency of the oil at low temperatures. In an engine we need the oil to flow back into the hole sucked out by the oil pump or else the pump will suck air and cause oil starvation.
 
Pour point is a low shear test that terminates when the oil fails to pour after slow cooling. Instead of measuring viscosity at a fixed temperature, it measures the temperature at which the oil is too thick to pour. Like the MRV it is affected by wax (gelling) if present, otherwise the test stops when the oil is just too thick to move within five seconds when the tube is rotated 90 degrees. It does not correlate to low temperature oil pumping and flow characteristics in a engine and is more useful in determining storage conditions. I ran thousands of them back in my lab days.

Yes if an oil has a pour point of -60°C it will still be liquid and pourable at -35°C but rather thick. As a reference, a POE jet engine oil with a pour point of -57°C would have a viscosity @ -40°C of about 8,000 cSt.
 
Pour point is a low shear test that terminates when the oil fails to pour after slow cooling. Instead of measuring viscosity at a fixed temperature, it measures the temperature at which the oil is too thick to pour. Like the MRV it is affected by wax (gelling) if present, otherwise the test stops when the oil is just too thick to move within five seconds when the tube is rotated 90 degrees. It does not correlate to low temperature oil pumping and flow characteristics in a engine and is more useful in determining storage conditions. I ran thousands of them back in my lab days.

Yes if an oil has a pour point of -60°C it will still be liquid and pourable at -35°C but rather thick. As a reference, a POE jet engine oil with a pour point of -57°C would have a viscosity @ -40°C of about 8,000 cSt.
So looking at 2 oils of the same grade, would a 4000 ccs@40 oil be thicker, at start up, than a 5500 ccs@40 oil?
 
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So looking at 2 oils of the same grade, would a 4000 ccs@40 oil be thicker, at start up, than a 5500 ccs@40 oil?
You talking about 40C or -40C? CCS viscosity in SAE J300 is only defined for temperatures in the negative Celsius realm.

Think it's been pointed out before in these discussions that you can't judge what the viscosity will be way below 40C by looking at the viscosity at 40C (KV40) between two different oils (if that's what you're getting at).

The only thing you really need to be concerned about in terms of cold start-ups is that the correct "W" rating is used.

SAE J300 defines both the CCS (per ASTM D5293) and MRV (per ASTM D4684) viscosity for adequate cold viscosity ratings (the "W" winter rating).

 
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You talking about 40C or -40C? CCS viscosity in SAE J300 is only defined for temperatures in the negative Celsius realm.

Think it's been pointed out before in these discussions that you can't judge what the viscosity will be way below 40C by looking at the viscosity at 40C (KV40) between two different oils (if that's what you're getting at).

The only thing you really need to be concerned about in terms of cold start-ups is that the correct "W" rating is used.

SAE J300 defines both the CCS (per ASTM D5293) and MRV (per ASTM D4684) viscosity for adequate cold viscosity ratings (the "W" winter rating).

Thanks. I was looking within the grade at the ccs spec. My facts: PUP 0w-20 ccs@40 PDS states the ccs is 5670 (incorrect?) while M1 AFE 0w-20 is 4182, so, is a lower ccs # preferable to a higher ccs# within the same grade? This difference is so great I believe the Pennzoil PDS is wrong. Probably, closer to the AFE#.
 
Thanks. I was looking within the grade at the ccs spec. My facts: PUP 0w-20 ccs@40 PDS states the ccs is 5670 (incorrect?) while M1 AFE 0w-20 is 4182, so, is a lower ccs # preferable to a higher ccs# within the same grade? This difference is so great I believe the Pennzoil PDS is wrong. Probably, closer to the AFE#.
Both of those numbers would be correct, the limit for CCS for a 0w-xx is 6,200cP @ -35C (not -40C):
SAE J300 - Current.png
 
Thanks. I was looking within the grade at the ccs spec. My facts: PUP 0w-20 ccs@40 PDS states the ccs is 5670 (incorrect?) while M1 AFE 0w-20 is 4182, so, is a lower ccs # preferable to a higher ccs# within the same grade? This difference is so great I believe the Pennzoil PDS is wrong. Probably, closer to the AFE#.
Pennzoil says 0W-20 PUP has a CCS of 5670 at -35C (not "@40" like you keep posting), and MRV of 14,700 at -40C (minus 40C, not plus 40C).
In fact, the SAE J300 only defines the CCS down to -35C ... NOT -40C (see post #11 above).

Mobil doesn't even show a CCS for their 0W-20 AFE that I can see. You have a link that does show it? Note - Mobil's website sucks, hard to get information, and they hardly give any useful oil spec info.

The information seems messed up. What's the Mobil 0W-20 CCS at -35C ?

So, assuming PUP CCS is 5670 cP at -35C and M1 AFE CCS is 4182 cP at -35C, then the M1 is "thinner" at -35C. Both rate as a 0W per SAE J300, obviously because both are thinner than 6200 cP at -35C.
 
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Pennzoil says 0W-20 PUP has a CCS of 5670 at -35C (not "@40" like you keep posting), and MRV of 14,700 at -40C (minus 40C, not plus 40C).
In fact, the SAE J300 only defines the CCS down to -35C ... NOT -40C (see post #11 above).

Mobil doesn't even show a CCS for their 0W-20 AFE that I can see. You have a link that does show it?

The information seems messed up. What's the Mobil 0W-20 CCS at -35C ?
I think he's going by the PQIA sheet:

Screen Shot 2022-03-09 at 5.33.42 PM.jpg
 
Pennzoil says 0W-20 PUP has a CCS of 5670 at -35C (not "@40" like you keep posting), and MRV of 14,700 at -40C (minus 40C, not plus 40C).
In fact, the SAE J300 only defines the CCS down to -35C ... NOT -40C (see post #11 above).

Mobil doesn't even show a CCS for their 0W-20 AFE that I can see. You have a link that does show it? Note - Mobil's website sucks, hard to get information, and they hardly give any useful oil spec info.

The information seems messed up. What's the Mobil 0W-20 CCS at -35C ?

So, assuming PUP CCS is 5670 cP at -35C and M1 AFE CCS is 4182 cP at -35C, then the M1 is "thinner" at -35C. Both rate as a 0W per SAE J300, obviously because both are thinner than 6200 cP at -35C.
Thanks, again. You're right. I had looked at the chart sometime ago
 
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