Originally Posted By: webfors
Answer: They can. Chances are they are more expensive than a 5wXX or 10wXX, so it's a waste of money when average temps don't require it.
The same is true for High Temps! You dont see people hunting down the 0w50 Eneos for when they live in Death Vallex, AZ! That oil is likely a 40wt. at Normal Temp anyway, not a 50..
I think a great example is 5W-40. Its the Euro formula on a lot of oils.. people SAY it is thinner than a 0W at cold temp, but when it warms up its closer to 40 than a 0W would be. (Thick 5, thin 40, and before yall chop my head off, talking about 5 NOT as a viscosity, but as a factor in the viscosity range of how thick it is vs a lower W nnumber of same KV.)
Always amazed me how you can run 0W-20 in a 7.4L Powerstroke, or whatever that V10 Excursion (Gasoline) is.
Are there those that believe Ambient Temp does not make a difference? For example, 110 degree steamy sticky sauna-like Miami in July, maybe hotter. Idling in traffic then drive for 40 minutes to beach. Thick Oil there? The cars that FF 5W-20 do fine... ?