Newbie question: Difference between SAE!

[Saad]

Hello, My Father owns an OIL&Battery shop and he had to travel and leave the business for me. Now i would like to knows whats the difference between 5W30 , 10W40 (Does it only come Synthetic), 20W50 and 40?? To what cars do we use them?

I have lots of different oil brands like: Castrol GTX, Castrol Magnatec, Duckhams Qplus, AcDelco, Some UAE Lubs, Titan Fuchs, Motul 2100+ , and Mobil SuperXHP, Shell Ultra , Shell Plus, Veedol, Champion, Streett.. etc.

I live in Lebanon which has a Mediterranean climate coldin winter and hot in summer.

 

[ProfPS]

For a brief explanation, the multi grade (viscosity) motor oil weights you listed show the tested viscosity of the oil in cold temperatures and hot temperatures – the tests are industry standards. The first number indicates the cold temperature viscosity and the second number is the hot temperature viscosity. For example, 5w-30 should act as a SAE 5 in cold temps and act as a SAE 30 in hot temps. There are many ingredients in motor oil that affects oil characteristics. Continue reading posts and you will pickup more information from posted entries.

The brands you listed seem to be good oil brands. To be safe, please check your car’s owner’s manual. Selecting oil viscosity is dependent on the engine and climate temperature during the oil use.

 

[simple_gifts]

The numbers 30, 40, 50 refer to the weight of the oil at operating temperature, the higher the number, the thicker the oil is when the engine is running.

http://www.bobistheoilguy.com/visc.html

The "W" numbers refer to the cold weather properties of the oil. A 5W oil will flow better when cold than a 10W.

It is better to check the owners manual to find out what viscosity oil is recommended by the manufacturer. Many manufacturers recommend different oil viscosities for the same vehicle depending on where in the world the vehicle is sold.

As a point of reference, in the US, the only gasoline vehicles that use 40 weight oil (5W-40) are German. All other vehicles use 30 weight or 20 weight. (5W-30, 5W-20)

 

[Pablo]

http://www.api.org/certifications/engineoil/categories/upload/EngineOilGuide2006.pdf

http://www.infineum.com/information/api-viscosity-2004.html

http://www.api.org/certifications/engineoil/pubs/index.cfm

http://www.api.org/certifications/engineoil/pubs/upload/1509_16thedition042007.pdf

http://pws.cablespeed.com/~pablomail//LINKS1.html

 

[Saad]

Thank you guys, appreciate the help!