So what do all the different oil weight numbers mean?

[5spd GT]

I did a quick search and couldn't find the one thread about oil weights and what they mean. I know Mr. Yount, JT, and some others posted in it and it was quite informative...

Enlighten me and others...What do the numbers relate too?

 

[88Stangboy]

The number before the 'W' (for Winter ) is the oil's viscosity when cold. The number after the 'W' is its viscosity at operating temperatures.

 

[HISSIN50]

Hey David. The numbers relate to temps and flow.

In multi-weights, the first number (5W, 10W, etc) is how the oil flows when it is cold (32*F).

The second number is how the oil behaves when it is hot (100*C/212*F).

So a 20W-50 will flow 'no thicker' than a 20 weight when at 32*F and will not thin out more than a 50 weight at 212*F.

I see big plans are in motion. I hope parts are coming in.

 

[srothfuss]

Yeah what Hissin said!

 

[dragnazz5.0]

www.bobistheoilguy.com thats everything you ever wanted to know about oil

 

[5spd GT]

So what does the "weighted" number come from. It's just a scale I guess or does it mean more...

Basically I'm wondering (for a lame example) does the 5w mean it takes 5lbs of pressure to go flow a certain amount at 32F?

Thanks for the replies...very helpful!