Can someone please explain what the numbers in oil ratings are?!
#2
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5w is the cold viscosity rating, 30 is the hot viscosity rating, W stands for winter. Is it just a multiviscosity oil, 5w means in the cold the oil can be pumped through the engine as if it was straight SAE 5 weight oil. To my knowlege there is no set temperature for testing the low viscosity rating but I may be wrong. The 30 means the oil at 100*C/212*F will pump like straight SAE 30 weight oil.
#3
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Here is a link that can teach you everything you ever wanted to know about this topic:
http://www.bobistheoilguy.com/motor-oil-101/
http://www.bobistheoilguy.com/motor-oil-101/
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