Well the oil was down about a 1/3 of a quart after this trip. Drove to Fargo this past weekend and checked it. Its was more than a quart low. So apparently the 5W40 slows the oil loss up to about 2000 miles then its back to normal loss levels (quart every 500 to 700 miles) Mileage is now about 104K. I think I'll change it at 3000 miles but this time I'll try conventional 15W 40 oil and see what happens. Anybody know if this is not a good idea? Too thick?