Cold flow properties
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The temps you're talking about are in Celsius, not Fahrenheit also
Originally Posted By: dpaldino
Just looking at Pennzoil Platinum PDS comparing cold flow temps of 0W-20 and 5W-20 flavors. Can't figure out why the 5W-20 flows at -51 and the 0W-20 flows at -48. Shouldn't the 0W flow at a lower temp?
"Pour point" is not the same as CCS or MRV. I would expect the 0w to have the lower CCS and MRV values which more accurately predict ability to be pumped and flow in a running engine at extreme temps. If you look at the link below...CCS and MRV are also higher for the 0w....but notice that they also test at different temperatures. So the best flow properties occur with the 0W. IIRC you might have to double the CCS/MRV values for every change of 5 deg C.
Pour points used to be all anyone looked at for low flow capabilities. They have now been supplemented and/or replaced by CCS/MRV.
Pennzoil 5W-20 spec sheet
Just looking at Pennzoil Platinum PDS comparing cold flow temps of 0W-20 and 5W-20 flavors. Can't figure out why the 5W-20 flows at -51 and the 0W-20 flows at -48. Shouldn't the 0W flow at a lower temp?
"Pour point" is not the same as CCS or MRV. I would expect the 0w to have the lower CCS and MRV values which more accurately predict ability to be pumped and flow in a running engine at extreme temps. If you look at the link below...CCS and MRV are also higher for the 0w....but notice that they also test at different temperatures. So the best flow properties occur with the 0W. IIRC you might have to double the CCS/MRV values for every change of 5 deg C.
Pour points used to be all anyone looked at for low flow capabilities. They have now been supplemented and/or replaced by CCS/MRV.
Pennzoil 5W-20 spec sheet
Edited
Still don't get why an 0W-20 doesn't pour as well as the 5W-20 oil. I could see if they were different brands or if one was synthetic and the other dino. If you take the exact same oil brand but different grades, I would expect the thinner oil to flow, pump, pour and lubricate more easily than a thicker oil at low temperatures but that doesn't seem to be the case here. If I put 0W-20 in my engine, I would expect it to perform better at low temps than a 5W-20. If that is not the case, then what advantage would a 0W-20 oil be providing over the 5W-20 grade?
Originally Posted By: dpaldino
Still don't get why an 0W-20 doesn't pour as well as the 5W-20 oil. I could see if they were different brands or if one was synthetic and the other dino. If you take the exact same oil brand but different grades, I would expect the thinner oil to flow, pump, pour and lubricate more easily than a thicker oil at low temperatures but that doesn't seem to be the case here. If I put 0W-20 in my engine, I would expect it to perform better at low temps than a 5W-20. If that is not the case, then what advantage would a 0W-20 oil be providing over the 5W-20 grade?
I don't blame you for being confused. After all this site, as well as many others, always talks about flow and protection and most equate better flow with better protection. This is true in a splash lubricated system, totally false in 100% of automotive applications that are even remotely modern.
0W means the oil will be pumpable at -40C
5W means the oil will be pumpable at -35C
10W means the oil will be pumpable at -30C
15W means the oil will be pumpable at -25C
This means that the oil will be able to flow into the oil pump inlet and then be pumped throughout the system. Better flow means nothing because the oil only has to flow into the inlet at the same rate the pump displaces it. Basically it has to keep up with the pump. It is the pump that dictates the rate of flow, so it makes little difference if one oil flows better than the other, because a positive displacement pump will move the same rate of fluid regardless of its viscosity.
Centrifugal pumps change the rate of flow with fluid viscosity, not positive displacement pumps.
And before anybody says "what about the oil return? It's gravity", well, so is the feed to the oil pump inlet
Still don't get why an 0W-20 doesn't pour as well as the 5W-20 oil. I could see if they were different brands or if one was synthetic and the other dino. If you take the exact same oil brand but different grades, I would expect the thinner oil to flow, pump, pour and lubricate more easily than a thicker oil at low temperatures but that doesn't seem to be the case here. If I put 0W-20 in my engine, I would expect it to perform better at low temps than a 5W-20. If that is not the case, then what advantage would a 0W-20 oil be providing over the 5W-20 grade?
I don't blame you for being confused. After all this site, as well as many others, always talks about flow and protection and most equate better flow with better protection. This is true in a splash lubricated system, totally false in 100% of automotive applications that are even remotely modern.
0W means the oil will be pumpable at -40C
5W means the oil will be pumpable at -35C
10W means the oil will be pumpable at -30C
15W means the oil will be pumpable at -25C
This means that the oil will be able to flow into the oil pump inlet and then be pumped throughout the system. Better flow means nothing because the oil only has to flow into the inlet at the same rate the pump displaces it. Basically it has to keep up with the pump. It is the pump that dictates the rate of flow, so it makes little difference if one oil flows better than the other, because a positive displacement pump will move the same rate of fluid regardless of its viscosity.
Centrifugal pumps change the rate of flow with fluid viscosity, not positive displacement pumps.
And before anybody says "what about the oil return? It's gravity", well, so is the feed to the oil pump inlet
To a large extent that is true. The same volume goes out whether it's 10W or 0W as long as it's still liquid and will feed the pump. In part, that is why the whole Oil U 101 thing about cold flow is a red herring. As long as the lubricant is above its pumpability limit, it'll get there the same.
Now a splash lubricated engine like an aircooled tool motor or something is a whole nuther can of worms. Since there is no pump, you definitely want a nice free flowing liquid so that it gets tossed around easily after start. Most of these engines sit for a long time between starts, so a fresh oil supply is more critical. Say a snow blower. 0W-30 would be my choice if I had to start one ...
Now a splash lubricated engine like an aircooled tool motor or something is a whole nuther can of worms. Since there is no pump, you definitely want a nice free flowing liquid so that it gets tossed around easily after start. Most of these engines sit for a long time between starts, so a fresh oil supply is more critical. Say a snow blower. 0W-30 would be my choice if I had to start one ...
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Originally Posted By: slybunda
Thats odd threads on here say that a thinner oil flows faster and in more quantity than a thicker oil. ?
Somewhere I have seen a video of two identical engines stored in a -30 deg C walk in/drive in freezer. The valve covers were removed and the engines were started. One had 10w-30 Dino and the other 5w-30 syn. The syn reached the top end much quicker. Even though the pumps may be pos displacement I imagined the difference being how much better the syn flowed into the pump inlet or maybe less escaped through some kind of pressure relief valve. Either way not too many people in the lower 48 need to worry about -48 vs -51 pour points. Just as long as the pour point is less than ambient temps. Nevertheless I would expect the 0w to have the lower PP. Maybe the two values are even within error bars of each other.
Thats odd threads on here say that a thinner oil flows faster and in more quantity than a thicker oil. ?
Somewhere I have seen a video of two identical engines stored in a -30 deg C walk in/drive in freezer. The valve covers were removed and the engines were started. One had 10w-30 Dino and the other 5w-30 syn. The syn reached the top end much quicker. Even though the pumps may be pos displacement I imagined the difference being how much better the syn flowed into the pump inlet or maybe less escaped through some kind of pressure relief valve. Either way not too many people in the lower 48 need to worry about -48 vs -51 pour points. Just as long as the pour point is less than ambient temps. Nevertheless I would expect the 0w to have the lower PP. Maybe the two values are even within error bars of each other.
I'd want to know the engine topology and the filters used and the relief valve settings and all. I also want to know why they would put a 10W up against a 5W in a test like that. It's built in bias. Ether make them both 5W's, or both 10W's, or both dinos, or both syns from the same refiner. I'm calling bovine ca-ca on this one.
Not that you did not see what they wanted you to see, but that they were not testing the same thing ... We don't know who's 10W-30 like maybe one of the PQIA banned oils ... And maybe a really slippery syn ... True synthetics have lower surface tension and less propensity to gel than most dinos. One was at the pour point limit and one had headroom to spare. Anyone here on BITOG knows what to do when the thermometer goes below 20*F or so.
Not that you did not see what they wanted you to see, but that they were not testing the same thing ... We don't know who's 10W-30 like maybe one of the PQIA banned oils ... And maybe a really slippery syn ... True synthetics have lower surface tension and less propensity to gel than most dinos. One was at the pour point limit and one had headroom to spare. Anyone here on BITOG knows what to do when the thermometer goes below 20*F or so.
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Originally Posted By: Carbon12
Originally Posted By: slybunda
Thats odd threads on here say that a thinner oil flows faster and in more quantity than a thicker oil. ?
Somewhere I have seen a video of two identical engines stored in a -30 deg C walk in/drive in freezer. The valve covers were removed and the engines were started. One had 10w-30 Dino and the other 5w-30 syn. The syn reached the top end much quicker. Even though the pumps may be pos displacement I imagined the difference being how much better the syn flowed into the pump inlet or maybe less escaped through some kind of pressure relief valve. Either way not too many people in the lower 48 need to worry about -48 vs -51 pour points. Just as long as the pour point is less than ambient temps. Nevertheless I would expect the 0w to have the lower PP. Maybe the two values are even within error bars of each other.
Yep, in reasonable negative temps, the 0w and the 10w will still get pumped to where they need to go to prevent damage just the 0w will beat it to the punch. That being said, I just run 10w40 year round in my truck (i plug in often) and don't have any noises or any concerning behavior from the oil pressure gauge. SOME modern oils, even 10wts, can be very stout cold weather performers without the need to move to a 0w oil.
Still I find the people that only have cold temperatures dip down for a few days or so dont need to change anything . The people with sustained temperatures below 0F for any length of time really should have a block heater/oil pan heater anyway and then..... you dont need to change much either. If you find yourself in a situation that you frequently can't plug in and you are sustained well below freezing for weeks or months then you have a need for these 0w oils.
Originally Posted By: slybunda
Thats odd threads on here say that a thinner oil flows faster and in more quantity than a thicker oil. ?
Somewhere I have seen a video of two identical engines stored in a -30 deg C walk in/drive in freezer. The valve covers were removed and the engines were started. One had 10w-30 Dino and the other 5w-30 syn. The syn reached the top end much quicker. Even though the pumps may be pos displacement I imagined the difference being how much better the syn flowed into the pump inlet or maybe less escaped through some kind of pressure relief valve. Either way not too many people in the lower 48 need to worry about -48 vs -51 pour points. Just as long as the pour point is less than ambient temps. Nevertheless I would expect the 0w to have the lower PP. Maybe the two values are even within error bars of each other.
Yep, in reasonable negative temps, the 0w and the 10w will still get pumped to where they need to go to prevent damage just the 0w will beat it to the punch. That being said, I just run 10w40 year round in my truck (i plug in often) and don't have any noises or any concerning behavior from the oil pressure gauge. SOME modern oils, even 10wts, can be very stout cold weather performers without the need to move to a 0w oil.
Still I find the people that only have cold temperatures dip down for a few days or so dont need to change anything . The people with sustained temperatures below 0F for any length of time really should have a block heater/oil pan heater anyway and then..... you dont need to change much either. If you find yourself in a situation that you frequently can't plug in and you are sustained well below freezing for weeks or months then you have a need for these 0w oils.
Originally Posted By: Carbon12
Somewhere I have seen a video of two identical engines stored in a -30 deg C walk in/drive in freezer. The valve covers were removed and the engines were started. One had 10w-30 Dino and the other 5w-30 syn. The syn reached the top end much quicker.
In those conditions, you're testing the limits of the cold cranking and MRV values of the oils in question. It has nothing to do with pour point. -30 C exceeds the cold cranking limits of a 10w-XX. That's what these videos are supposed to show. They're not showing differences in flow at normal temperatures, or the value of a pour point measure. They simply show that at -30 C, you are stepping outside the limits of a 10w-XX oil. If you can't pump the oil in the first place, it's not going to flow.
The Esso video on Youtube shows what happens when you try to simply pump an oil outside of its temperature limits. Look at SAE J300, courtesy of Richard Widman:
Somewhere I have seen a video of two identical engines stored in a -30 deg C walk in/drive in freezer. The valve covers were removed and the engines were started. One had 10w-30 Dino and the other 5w-30 syn. The syn reached the top end much quicker.
In those conditions, you're testing the limits of the cold cranking and MRV values of the oils in question. It has nothing to do with pour point. -30 C exceeds the cold cranking limits of a 10w-XX. That's what these videos are supposed to show. They're not showing differences in flow at normal temperatures, or the value of a pour point measure. They simply show that at -30 C, you are stepping outside the limits of a 10w-XX oil. If you can't pump the oil in the first place, it's not going to flow.
The Esso video on Youtube shows what happens when you try to simply pump an oil outside of its temperature limits. Look at SAE J300, courtesy of Richard Widman:
So due to chemical makeup of a particular oil it can be thicker in all regards but have a better cold crank than an oil that is thinner in viscosity?
Example I am thinking of right now is Castrol Edge A3/B4 5W30 vs Castrol Edge 10W30. The 10W30 is actually thinner in KV40 and KV100 and HTHS as it is aimed at fuel economy. The Edge 5W30 A3/B4 is thicker in all regards due to being aimed at the Euro specs. So despite being thicker on all counts, the Edge 5W30 flows better because something in it's chemistry allows it to still crank at -30 C whereas the 10W30 cannot?
Or did I use the wrong word "flow" there? Wouldn't the thinner 10W30 be better for cold starts, for example, somewhere where it does not go -0 C?
Example I am thinking of right now is Castrol Edge A3/B4 5W30 vs Castrol Edge 10W30. The 10W30 is actually thinner in KV40 and KV100 and HTHS as it is aimed at fuel economy. The Edge 5W30 A3/B4 is thicker in all regards due to being aimed at the Euro specs. So despite being thicker on all counts, the Edge 5W30 flows better because something in it's chemistry allows it to still crank at -30 C whereas the 10W30 cannot?
Or did I use the wrong word "flow" there? Wouldn't the thinner 10W30 be better for cold starts, for example, somewhere where it does not go -0 C?
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Originally Posted By: KL31
Or did I use the wrong word "flow" there? Wouldn't the thinner 10W30 be better for cold starts, for example, somewhere where it does not go -0 C?
Yeppers..."flow" is (I believe purposely) misinterpreted depending on context often on BITOG.
-25 to -35C, the edge 5W30 will "flow" better to places like the oil pick-up tube than the 10W30 oil, to be shifted to the galleries and remote places...by "flowing" better to the pick-up at those temperature extremes, its "flow" "protects better".
Think sucking a thickshake up a straw wrt "flow"
Both oils at 0C, there is no problem getting the oil to the pump (thickshake effect), and so from that point onwards, the pump is pushing the same volume per revolution through the galleries, filling that volume at around the same rate.
The "W" ratings are made of two parts:
* the CCS, which is the ability of the engine to turn at a sufficient speed to start
* the MRV, which is the ability of the oil to flow into the pickup tube.
You can get into strange places at temperatures where you and I will never see.
An engine can start, and the MRV be so high that the oil can't reach the pump. One reason is that the MRV is so high that the oil in the pickup tube "separates" and the pump sucks nothing. Other is that the oil can't "fill" the cavity that the suction leaves as the oil tries to cave back into in the sump, and the pump sucks air (air binding).
In either of those places, "cold start" "flow" is important, and prevents engine failure.
In temperatures where neither of these effects exist, i.e. above freezing..."flow" is about the same in all respects.
Or did I use the wrong word "flow" there? Wouldn't the thinner 10W30 be better for cold starts, for example, somewhere where it does not go -0 C?
Yeppers..."flow" is (I believe purposely) misinterpreted depending on context often on BITOG.
-25 to -35C, the edge 5W30 will "flow" better to places like the oil pick-up tube than the 10W30 oil, to be shifted to the galleries and remote places...by "flowing" better to the pick-up at those temperature extremes, its "flow" "protects better".
Think sucking a thickshake up a straw wrt "flow"
Both oils at 0C, there is no problem getting the oil to the pump (thickshake effect), and so from that point onwards, the pump is pushing the same volume per revolution through the galleries, filling that volume at around the same rate.
The "W" ratings are made of two parts:
* the CCS, which is the ability of the engine to turn at a sufficient speed to start
* the MRV, which is the ability of the oil to flow into the pickup tube.
You can get into strange places at temperatures where you and I will never see.
An engine can start, and the MRV be so high that the oil can't reach the pump. One reason is that the MRV is so high that the oil in the pickup tube "separates" and the pump sucks nothing. Other is that the oil can't "fill" the cavity that the suction leaves as the oil tries to cave back into in the sump, and the pump sucks air (air binding).
In either of those places, "cold start" "flow" is important, and prevents engine failure.
In temperatures where neither of these effects exist, i.e. above freezing..."flow" is about the same in all respects.
Originally Posted By: KL31
So due to chemical makeup of a particular oil it can be thicker in all regards but have a better cold crank than an oil that is thinner in viscosity?
You have to report an Oil at the lowest XW grade possible with multigrade oils. So if an oil has a chemical makeup that performs better in CCS/MRV it has to be reported as such (You can't claim an oil to be a 5W30 if it meets the specs of a 0W30.)
If you are asking about Viscosity - you have to be careful because viscosity can be measured in several ways. If you are talking about the Viscosity Grade then yes think about a 0W40 oil which has a higher Kinematic viscosity@100C than a 5W30 oil, but has better CCS/MRV values). This holds true for your Castrol Edge example as well.
Similarly Pour point could be effected by lots of things - including concentration of pour point depressants. So you can get a 5W30 oil with a lower pour point than a 0W30 oil depending on how it is made.
If they ever get around to publishing the updated Oil 101 we put together some of this will be cleared up there. Thinner oil does flow better, but in the reality of an engine with PD pumps it is probably more correct to say it requires less energy to pump thinner oil than thicker oil - and that is where the advantage is because less energy to move the oil means less stress on the pump and greater fuel economy.
So due to chemical makeup of a particular oil it can be thicker in all regards but have a better cold crank than an oil that is thinner in viscosity?
You have to report an Oil at the lowest XW grade possible with multigrade oils. So if an oil has a chemical makeup that performs better in CCS/MRV it has to be reported as such (You can't claim an oil to be a 5W30 if it meets the specs of a 0W30.)
If you are asking about Viscosity - you have to be careful because viscosity can be measured in several ways. If you are talking about the Viscosity Grade then yes think about a 0W40 oil which has a higher Kinematic viscosity@100C than a 5W30 oil, but has better CCS/MRV values). This holds true for your Castrol Edge example as well.
Similarly Pour point could be effected by lots of things - including concentration of pour point depressants. So you can get a 5W30 oil with a lower pour point than a 0W30 oil depending on how it is made.
If they ever get around to publishing the updated Oil 101 we put together some of this will be cleared up there. Thinner oil does flow better, but in the reality of an engine with PD pumps it is probably more correct to say it requires less energy to pump thinner oil than thicker oil - and that is where the advantage is because less energy to move the oil means less stress on the pump and greater fuel economy.
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