Right im ready to put oil in the focus to start the running in, now my dad went to car accessory shop this morning to get me some mineral oil.

The shop sold him valvoline 15w40 diesel oil lol they said that's the best stuff to use?

Im not to sure so can anybody shed some light please.

Its for a focus rs just had new rings.

 

It won't hurt it mate.

 

Diesel oil is fine in a petrol car