oil question what do the numbers mean?

[turbotobes]

hi guy jus curious as to what the last number on the oil bottle means. I know that the the first two and the W mean the weight (thats how thick it is right?) but don know what the other two mean eg. 20w50 = 20weight ??

sorry about the noob-ee-ness :cheeky-smiley-031:

thanks in advance ppl

 

[mattbombers]

idk, i just look for "castrol active 4t" and walk out lol

 

[turbotobes]

lol me to but im one of those ppl that just likes to know

Oh but i pay for it first lol

 

[Possum]

20w at operating temp and 50w when its cold it thins out when hot
Same as when you put oil on a bbq it thins out as it heats up correct me if im wrong!

 

[sean01]

ok been a while since i had to worry about this sorta stuff but for example...
20w50 is the minimum and maximum viscosity of the oil.. oil being multigrade these days are designed for hot and cold climates so at different temps it has different thickness..
20w when cold and 50w when very hot

 

[topguntravis]

The numbers are the viscosity of the oil. The first number is its "cold" viscosity and the second number is its "hot" viscosity. Basically a range of the viscosity from cold temperatures to hot temperatures.

Viscosity is the oils resistance to flow. (Honey is a great example, when it's cold it flows slowly (more resistant) and when it's heated/hot it flows faster (less resistant).

The "W" is just saying it meets a low temperature requirement and for practical purposes perhaps better to use in winter, however this isn't really relevant to us.

 

[turbotobes]

ok cool thank sean and possum i new som1 one here would know :action-smiley-033:

 

[sean01]

and just for reference Explain Motor Oil Weights | eHow.com