I have a ford E350 ford box truck with 95000 miles.The truck is mixed NYC and suburban deliveries.OIl changes are hard to do for the reason of time,the truck is used six days a week so no real time to drop off the truck for an oil change, and its, the oil change nobdy wants to do because you cant pull it into the garage bay.So i been doing it myself but it,s a pain,really no time for it.What oil should I use and at what milelage sould it be done at.The truck calls for 5/20 but i like 5/30 better.The 20 wght burns to quick with the heavy loads it carries