I have used all the Scheaffer products and tried others but go back to the Scheaffers
I now use there Soyshield and it seems to return the best mpgs it is an all season product also so no need to buy a summer / winter supplement. And the price is right
I run Scheaffers 15-40w syn blend in the 2000 f250 193000 miles
And in the 2003 f350 i run there 5-40w syn
it gets pretty darn cold here in St. Louis and i cannot say the F250 starts any different than F350