thickness diffrences between diff. 10/30

DOC

Messages
28
Location
SO Calif
I usually use Valvoline 10/30. I needed a quart and picked up a Mobil semi snythetic in the same weight. The Mobile appeared thicker while pouring. Why do various oils with the same weight have different pouring characteristics? Does this effect there ability to lubricate?
 
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47,640
Location
Duvall WA - Pacific NW USA
In a nutshell, the SAE viscosity specifications (aka "grade") are a range, not one number. One oil could be at the low end of the range, the other the high end and still be call a 10W-30. This of course is at whatever temp. you are pouring at (unlikely 100°C, so not the 30), and is only a pouring apparent viscosity in the eye of the beholder, not a true vis. measurement...
 
Messages
47,640
Location
Duvall WA - Pacific NW USA
Also let me add that the old "pouring like honey must be better" theme when out years ago. So, basically what you see with your eye has no bearing on the "ability to lubricate".
 
Messages
5,785
Location
Dixie
SAE, 0w-30/5w-30/10w-30 oils can have a viscosity in the following range: 9.3 to 12.5 Centistokes @ 100C/212F So two different 10w-30 oils can vary by up to 33% in terms of high temp viscosity ....The other grades vary as well: xw-20: 7.2?-9.3 Cst xw-40: 12.5-16.5 Cst xw-50: 16.5-20.5 Cst Tooslick [ February 15, 2004, 08:15 AM: Message edited by: rugerman1 ]
 
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