What do the numbers/letters mean.

[discobiscuit]

I'm sure you can tell by the question that I'm a "newbie" when it comes to oil. I've always done my own oil changes but that's about as far as my knowledge of oil extends.

Was hoping someong could tell me what the first two and last two numbers on the oil can mean. 10W-30, 5W-20...etc.

Thanks.

 

[Scum_Frog]

here you go...enjoy!

http://www.bobistheoilguy.com/motor-oil-101/

 

[Donald]

Welcome to BITOG. Understand the numbers but also follow the owners manual.

 

[fdcg27]

Hang out here for a while and you'll develop a good understanding of what these SAE grades mean, as well as what they don't tell you about an oil's viscosity at any given temperature.
HTHS might be the better measure of viscosity when the oil is at operating temperature, while MRV and CCS give more useful information than does the SAE 0W measurement in evaluating cold ambient temperature startup performance.
You can expect a long thick versus thin debate when 0W-16s hit the shelves this year.
It should be educational as well as entertaining, although if it gets too entertaining it's liable to get locked.

 

[Eddie]

Please notre that there is a MidTerm and Final Exam when you've finished the "Oil" classes, identified by Scum_Frog.