which is lighter
which is lighter which motor oil is lighter?
0w40 or 5w30?
im thinking 0 weight is lighter and thicker, but i don't know what the numbers mean.
reason im asking is because many folks over at corvetteforum are saying 0w40 and 10w40 are both better than the 5w30.
im thinking of switching over to Mobil 1 0w40. i think the 10w40 is a bit to heavy for stock motor and more suited for a non stock motor.
0w40 or 5w30?
im thinking 0 weight is lighter and thicker, but i don't know what the numbers mean.
reason im asking is because many folks over at corvetteforum are saying 0w40 and 10w40 are both better than the 5w30.
im thinking of switching over to Mobil 1 0w40. i think the 10w40 is a bit to heavy for stock motor and more suited for a non stock motor.
Last edited by c5_ls1_6spd; Apr 11, 2006 at 01:24 AM.
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At operating temperature the 5w30 will be lighter than the 0w40. The second number indicates the viscosity at 100c (212F) In order to be labeled a 30wt, the viscosity must be between 9.3 cst and 12.49 cst at 100c. In order to be labelled a 40wt it must be between 12.5 to 16.3 cst at 100c.
The first number refers to it's cold cranking ability. So the 0w oil will have better cold cranking ability than a 5w oil. It doesn't always necessarily mean the 0w oil is going to be thinner at normal temps though. For instance, German Castrol 0w30 flows very well in extreme cold, but it's viscosity at 40c (just over 100F) is actually thicker than most 5w30 oils. But since it uses such an exotic base oil, it has that ability to flow in extreme cold, without actually being a super thin oil under normal temperatures. That is one of the reasons I love it so much. It uses no viscosity index improvers either, so it's very shear stable. Mobil 1 0w40 is definitely better than Mobil 1 5w30, however the 0w40 does use a lot of viscosity index improvers and it tends to thin out quickly. It still stays thicker than the 5w30 though. But the better choice (if you don't go with Castrol 0w30) would be to run a good 5w40.
The first number refers to it's cold cranking ability. So the 0w oil will have better cold cranking ability than a 5w oil. It doesn't always necessarily mean the 0w oil is going to be thinner at normal temps though. For instance, German Castrol 0w30 flows very well in extreme cold, but it's viscosity at 40c (just over 100F) is actually thicker than most 5w30 oils. But since it uses such an exotic base oil, it has that ability to flow in extreme cold, without actually being a super thin oil under normal temperatures. That is one of the reasons I love it so much. It uses no viscosity index improvers either, so it's very shear stable. Mobil 1 0w40 is definitely better than Mobil 1 5w30, however the 0w40 does use a lot of viscosity index improvers and it tends to thin out quickly. It still stays thicker than the 5w30 though. But the better choice (if you don't go with Castrol 0w30) would be to run a good 5w40.
