Are 0w-40 and 5w-40 the same thickness when cold??

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144
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98281
Are 0w-40 and 5w-40 the same thickness when cold??. I read a post on this site that said they had exactly the same thickness at the winter rating and the only difference was that 0w-40 had a lower pour point. Could someone please clarify this for me.
 

Jay

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1,613
Location
Idaho Falls, ID
It depends on how you define "cold". If you know kinematic viscosity @ 100C and viscosity index you can calculate how thick the oil will be at the temp in question here.
 
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2,480
The answer is no. 40C is not cold and hence is not an accurate measure of 'cold' thickness. A 0 weight will be thinner at extreme cold because it has a lower standard cold test to qualify for. This is -35C.
 
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