My 99 24 v now has 100000 miles. it was broke in on dino oil and has used Delvac 1 5 / 40 syn ever since. BUT with the price of oil products up and my limited driving of the outfit I am considering changing back to dino oil( Delo400 LE diesel 15/40 w) available at Cosco for much less than Delvac 1 which is excellent oil but way expensive. Please give me your best thoughts on this so I can decide. Thanks