quick oil pump question

[banzai510(hainz)]

that Ford/others 15-40 has that additive.& Delo  for diesel motors

 

be honest those are all good weights.  If it stayed warmer I would just run straight 30 if they sold it at the local store.  

 

 

cold areas run the 10-30

[datzenmike]

Maybe I missed it but why is it better to run 15w-40, than 10-30 or 10-40 which is what my book says.

 

Multi grades are all the same 'thickness' when hot but lower numbers stay 'thinner' when they get cold. Think of bacon fat beginning to gel as it cools. Thinner or lower number oils make cranking the engine over when below freezing much easier. I didn't know there was a 10w30 Rotella T but my 15w40 seems ok so far but will see this winter. It barely gets to freezing here.

 

My new '76 B-210 had 10w30 in it the first winter (10F below or more) and the little starter would turn it, but soooo slooow it wouldn't even fire. I was told to try straight 10w, I did, and it made a hell of a difference. Ten weight oil is not recommended for highway driving above 60F.