Don't know if this is the best....good enough for me.
http://www.valvoline.com/carcare/articleviewer.asp?pg=ccr20040601ov
http://www.valvoline.com/carcare/articleviewer.asp?pg=ccr20040601ov
please explain again the winter W side of the viscosity label
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The "W" is a reference to "cold cranking" conditions, the oils are still 20, 30, 40, 50 etc. weight, on the other side. For example "Cold Crank Simulator Apparent Viscosity @ -30 degrees C, cP, ASTM D2602, for a 5W-30 might be <2310 and for a 10W-30 might be 1843 for comparison. And "Borderline Pumping Temperature", ASTM D3829 might be -47 F degrees for a 5W-30 and -42 F degrees for a 10W-30, only a 5 degree difference. Other factors are probably much more important than the "W" designation, as has already been pointed out.
OK. I thought I understood this but am slightly confused by the xW part on comparing oils with different viscocities. For example, I pulled these from Mobil's data:
OK. I thought I understood this but am slightly confused by the xW part on comparing oils with different viscosities. For example, I pulled these from Mobil's data:
0W-40 / 10W-30
14.4 / 9.8 Kinematic, cSt @ 100°C
80.3 / 61.3 Kinematic, cSt @ 40°C
21,700@-40° / 10,250@-30° (Cold Pumping, cP @ °C)
So, the 40 weight is thicker (more viscose) than the 30 weight at both 40C and 100C. At very low temperatures, the 40 weight may be thicker than the 30 weight, but will pump easier and flow better because of the 0W (versus 10W) properties. Is this correct
OK. I thought I understood this but am slightly confused by the xW part on comparing oils with different viscosities. For example, I pulled these from Mobil's data:
0W-40 / 10W-30
14.4 / 9.8 Kinematic, cSt @ 100°C
80.3 / 61.3 Kinematic, cSt @ 40°C
21,700@-40° / 10,250@-30° (Cold Pumping, cP @ °C)
So, the 40 weight is thicker (more viscose) than the 30 weight at both 40C and 100C. At very low temperatures, the 40 weight may be thicker than the 30 weight, but will pump easier and flow better because of the 0W (versus 10W) properties. Is this correct
No, the 0W will be thinner at extreme cold (below -25C) because it "qualifies" as having the ability to pump down to -40C whereas the 10W peters out at -25C.
Due to it's 40 weight, it will be thicker at temps. above say -10C than the 30 weight.
In other words, it won't make a difference if you live somewhere where it never gets to -40C.
Due to it's 40 weight, it will be thicker at temps. above say -10C than the 30 weight.
In other words, it won't make a difference if you live somewhere where it never gets to -40C.
Oil thickens and thins as temps change.
So the 10w might be thinner than the 0w at 40, but as it cools it thickens faster. Eventually overtaking the 0w in the viscosity department.
So the 10w might be thinner than the 0w at 40, but as it cools it thickens faster. Eventually overtaking the 0w in the viscosity department.
can't find the info,
if someone can post a link that would be cool.
my questions are, for a xW-30 versus xW-40 versus xW-50 oil, I understand that the 30, 40, & 50 numbers are the viscosity grade the oil is when at operating temp, which is 100C correct?
now with 0W-30, 5W-30 & 10W-30, what do the 0, 5, & 10 represent again? Is that number only representative of the pumpability when the oil is cold? At what temp? Does it have any relation to viscosity?
And how would the W numbers compare from a 5W-30 versus a 15W-40 or a 20W-50?
thanks
if someone can post a link that would be cool.
my questions are, for a xW-30 versus xW-40 versus xW-50 oil, I understand that the 30, 40, & 50 numbers are the viscosity grade the oil is when at operating temp, which is 100C correct?
now with 0W-30, 5W-30 & 10W-30, what do the 0, 5, & 10 represent again? Is that number only representative of the pumpability when the oil is cold? At what temp? Does it have any relation to viscosity?
And how would the W numbers compare from a 5W-30 versus a 15W-40 or a 20W-50?
thanks
Do a Google search for SAE J300 and look for the SAE J300 table that shows the viscosity requirements. That will give you a better explanation than anyone can give you with words.
The right hand number converts to a range of kinematic viscosities at 100C (212F), the smaller number before the W indicated winter viscosity. Two different tests are used and the temperature they are run at varies according to the number before the W.
The right hand number converts to a range of kinematic viscosities at 100C (212F), the smaller number before the W indicated winter viscosity. Two different tests are used and the temperature they are run at varies according to the number before the W.
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