Some of you may remember that I'm treating my Olds minivan (with 141,000 miles on it). I'm just about at the end of the 1500 mile first application, but I've got a bit of a dilema. Just about all of that mileage has been accumulated from short trips; virtually none of it was extended highway miles. However, I'll be taking the van on a 600+ mile trip for Christmas. Should I leave this oil and the Auto-Rx in there for the trip, or should I change it out and begin the first rinse cycle?