So Valvoline has a engine guarantee, I singed up both my truck and car "its free", but after reading terms and conditions its a bit silly. If you want the 300,000 mi "syn-power" full synthetic guarantee you have to do 3000 mi OCI on full synthetic ! kinda defeats the purpose of running syn in my opinion. Im just venting and wanted to share. I like Valvoline and will continue to use there product but i dunno if im gonna be doing 3000mi OCI. feel like i would be pulling the drain plug and throwing away money. I did however stock up on Synpower, $20 5qt jug at wally-world.