Storme. All oil's synthetic or refined crude will thin out when it
is heated. For example, oil's are rated for viscosity at two temperatures.
40*C and 100*C. Looking at Mobil 1 5W30 grade, it's viscosity at 40*C
is at 64.8 cSt. It's operating viscosity at 100*C is 11.3 cSt. As the
temperature goes up, the viscosity value goes down. The oposite is
true when the temperature drops, the viscosity value increases or gets
thicker when cold. The amount that the oil thickens is what gives an oil
the cold temperature characteristics number rating one see's before the
W. An oil that does not thicken as much will have a lower value before
the W. For example, a 0W30/40 will have a cranking viscosity of 3250 cp
at -35*C and a pumping viscosity of 60000 cp at -40*C. A 5W30/40/50
oil will have a cranking viscosity of say 35000 cp but at -25*C. It's
cranking viscosity of -60000 cp will be at -35*C. A 10W30 oil's cold
viscosity of 3500cp and 60000cp will be at -20*C. So you can see that
a 0W oil will not thicken up as much as say a 10W oil will. At normal
winter temperatures of -15 to 0 *C that most people encounter, there
isn't much difference in a oil's viscosity. If you were to get a bottle of
a 0W30/40 oil and another of a 5W40 oil and poured them out at the
same time somehow, it would almost be the same if these oil's were
both A3 Euro rated oil's. It's the number after the W that determines
the operating viscosity. I hope this helps Storme.
Linear Mode
