Engine Oils...

[silver_fern]

What do the '10/40', '20/50' etc. reference numbers mean on car engine oils?

[Toureman]

Those are SAE numbers, to learn all about car engine oils, click here........

http://www.carbibles.com/engineoil_bible.html

Scroll down a long way to SAE.

[kawasakizx10]

Hi ! Oils are very complex these days , but in a nutshell the 1st lower number is its effectiveness at low temp ie the 10 in a 10w/40 stands for -10,the w means winter! so that oil protects down to minus 10 degrees c, a 20w/50 protects down to minus 20 degrees ect. The higher number is the viscosity of the oil , all oil's are tested at 100 degrees centigrade so the lower the number the thinner the oil at this temp!ps a 10w/40 is thought to be the best oil for our climate.hope this helps but to be honest it's just the tip of the iceberg!!!.Regards Kev.

[Toureman]

I would suggest you read this Kwaka if you think 20W/50 protects down to minus 20 degrees.

http://www.castrol.com/castrol/genericarticle. do?categoryId=8264018&contentId=7007302

[Toureman]

I didn't want to put it as strong as that Woody, you do get some strange advice on the motoring section though.

[kawasakizx10]

Ok I got it wrong!! I actually got the information out of an haynes manual but instead of typing it from the text, I read the text in the garage then thought i could remember it ? but got it arse about tit as usual. SO instead of talking ****!! I just miss quoted the text.