0W vs 5W vs 10W viscosity curve?

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Hello everyone, I am wondering if anyone has any viscosity curves for 0W vs 5W and/or 10W oils with the same hot viscosity. I have tried to find example curves but I was not able to find anything and I am curious at about which temp the cold viscosity actually starts to significantly differ. On all the data sheets I have seen, the differences in kinematic viscosity between 0W, 5W, and 10W is negligible at 40 degrees C (104 degrees F). But what about on cold starts in moderate weather of, say, 60-80 degrees F? Cool but not bitterly cold weather (30-50 degrees or so)? I realize that the exact viscosities will vary depending on the exact oil, but if someone has some information or viscosity curves they could share that would be very helpful in helping me understand the approximate differences. Thanks in advance!
 
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💁‍♂️ low ccs and higher pumpability is what makes an oil’s winter rating

AF19612C-E263-4A55-BCBA-60B81F7BC839.jpeg
 

Avery4

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Thanks but I was looking for information on the operational viscosity of the different weights at different temps rather than simply the ranges the grades must fall within according to SAE standards.
 

ZeeOSix

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Hello everyone, I am wondering if anyone has any viscosity curves for 0W vs 5W and/or 10W oils with the same hot viscosity. I have tried to find example curves but I was not able to find anything and I am curious at about which temp the cold viscosity actually starts to significantly differ. On all the data sheets I have seen, the differences in kinematic viscosity between 0W, 5W, and 10W is negligible at 40 degrees C (104 degrees F). But what about on cold starts in moderate weather of, say, 60-80 degrees F? Cool but not bitterly cold weather (30-50 degrees or so)? I realize that the exact viscosities will vary depending on the exact oil, but if someone has some information or viscosity curves they could share that would be very helpful in helping me understand the approximate differences. Thanks in advance!
If your starting the engine at 60-80F then the W rating isn't going to matter one bit. You're going down a dead end rabbit hole. ;)
 

OVERKILL

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On the site that @kschachn linked, they also have a page for graphing oils, so if you have the KV40's and KV100's for different oils, you can see how they compare. I would edit the scale to show to -20*C to get a fuller perspective of the divergence.

-20C is too cold, it's well below the temperature accuracy limit of the calc.

Typically, one would use 0C as the cut-off, but one probably wouldn't be going too far into the weeds with -10C.
 
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-20C is too cold, it's well below the temperature accuracy limit of the calc.

Typically, one would use 0C as the cut-off, but one probably wouldn't be going too far into the weeds with -10C.
I was not familiar with the constraints of the calc, just going off minimum temps in my area.
 
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I've also been wondering about temperature and how it relates to the winter numbers on oil. My mother's vehicle - the Envoy listed in my sig - has a rather large oil usage issue. Due to financial limitations, it's anyone's guess as to when we will either be able to repair it or replace the vehicle altogether. My place of work - Advance Auto Parts - sells Chevron Delo 400 SDE and other HDEO oils with the SN spec in the 15w-40 variation in a gallon size for $20, which I can get for $16 with my employee discount. Or in 2.5-gallon sizes for $32 or $28.60 with the discount. I'm running this as it will be cheaper in the long run rather than the 5w-30 that is called for.

My concern is when it hits winter here in WI, it can get down to -30F. I'm concerned that running a 15w oil can cause damage to the engine at low temps like that because the pump will not be able to get it to the critical engine parts in time when it is that cold. At least, this is what I've read on other forums. What are the thoughts you all here have on this?
 

OVERKILL

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I've also been wondering about temperature and how it relates to the winter numbers on oil. My mother's vehicle - the Envoy listed in my sig - has a rather large oil usage issue. Due to financial limitations, it's anyone's guess as to when we will either be able to repair it or replace the vehicle altogether. My place of work - Advance Auto Parts - sells Chevron Delo 400 SDE and other HDEO oils with the SN spec in the 15w-40 variation in a gallon size for $20, which I can get for $16 with my employee discount. Or in 2.5-gallon sizes for $32 or $28.60 with the discount. I'm running this as it will be cheaper in the long run rather than the 5w-30 that is called for.

My concern is when it hits winter here in WI, it can get down to -30F. I'm concerned that running a 15w oil can cause damage to the engine at low temps like that because the pump will not be able to get it to the critical engine parts in time when it is that cold. At least, this is what I've read on other forums. What are the thoughts you all here have on this?
The Winter rating of the oil dictates the appropriate temperature range for the lubricant:

If we go by pumping (MRV) then the limits are as follows:
0W: -40C (-40F)
5W: -35C (-31F)
10W: -30C (-22F)
15W: -25C (-13F)
20W: -20C (-4F)

So if you legitimately encounter -30F temperatures, a 15W-xx is wholly inappropriate.
 

Avery4

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I've also been wondering about temperature and how it relates to the winter numbers on oil. My mother's vehicle - the Envoy listed in my sig - has a rather large oil usage issue. Due to financial limitations, it's anyone's guess as to when we will either be able to repair it or replace the vehicle altogether. My place of work - Advance Auto Parts - sells Chevron Delo 400 SDE and other HDEO oils with the SN spec in the 15w-40 variation in a gallon size for $20, which I can get for $16 with my employee discount. Or in 2.5-gallon sizes for $32 or $28.60 with the discount. I'm running this as it will be cheaper in the long run rather than the 5w-30 that is called for.

My concern is when it hits winter here in WI, it can get down to -30F. I'm concerned that running a 15w oil can cause damage to the engine at low temps like that because the pump will not be able to get it to the critical engine parts in time when it is that cold. At least, this is what I've read on other forums. What are the thoughts you all here have on this?
I personally would not use 15W oil in extreme cold, that's just asking for trouble. Really 10W is too thick for that kind of cold if you ask me.
 
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The Winter rating of the oil dictates the appropriate temperature range for the lubricant:

If we go by pumping (MRV) then the limits are as follows:
0W: -40C (-40F)
5W: -35C (-31F)
10W: -30C (-22F)
15W: -25C (-13F)
20W: -20C (-4F)

So if you legitimately encounter -30F temperatures, a 15W-xx is wholly inappropriate.
Thank you for the excellent response. Now I know that I need to avoid a 15w for sure when it starts to get bitter.

I personally would not use 15W oil in extreme cold, that's just asking for trouble. Really 10W is too thick for that kind of cold if you ask me.
Thank you for your response. It has helped answer my question.
 
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So actually I’ll run this for you and let you know. When you make 600VI suspension fluids it becomes a futile effort to try to get a meaningful curve generated from a calculation based on 2 points of information. To solve that I spent the money on a stabinger so we can measure 6 real points from -20C to 105C and then plot real numbers. It will take me a couple days to be able to get the time but I’ll get the actual curves.

David
 

Avery4

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Here is the measured and plotted data on a 0W, 5W, and 10W30. This is our premium plus which is PAO based. The changes would probably be larger in a group III
Awesome, thank you so much! I'm surprised how small the differences are, especially at the lower temperatures I was expecting a much bigger difference.
 

ZeeOSix

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Awesome, thank you so much! I'm surprised how small the differences are, especially at the lower temperatures I was expecting a much bigger difference.
Take note of the y-axis scale - it's logarithmic, not linear. If it was plotted on a linear y-axis it would show the difference better.
 
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Correct you are. It is in Log. That is why I included the table with the actual numbers we measured. We did not have a 10W30 in that series so I had to make one to be able to keep everything in the same group of base oil.

David
 
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A linear y-axis scaled to include the highest viscosity on that plot would make the lowest ones difficult to distinguish from each other---and from zero.
 
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