Motor Oil: Is there a difference between SAE 30 and 5W-30?

[aeroguy]

I accidentally bought two quarts of SAE 30 and normally use 5W-30 motor oil. What's the difference?

 

[Vette73]

30 weight is 30 weight at ALL times. That is not good for any car made in the last many decades.

Its ok to top your oil off with 30 weight, but not add a lot or change with it.


<-- 10w30 year round with 160k+ on the ole Buick

 

[aeroguy]

Thanks for the info.

 

[Minjin]

30 weight is good for breaking in an engine. But no, you definitely should not run that in a normal car.

Mark

 

[PandaBear]

Huge difference, there should be no reason anyone uses Straight SAE30 oil now, use 5w30 or 10w30.