I ran a hard (fast) 3800 mile trip from SW Missouri to Philadelphia, NYC, Myrtle Beach and back home in October. I had my oil changed after the first 1300 miles (M light came on). I had added a quart on the way east. On the next 2500 miles I went through 2.5 quarts of oil including the half quart I was down upon return to home. This is fairly consistent with my consumption for last 25-30,000 miles. Back home I had my oil changed again but sprung for Mobile 1 High Mileage 5w-30. That was a little over 500 miles ago and I have not seen the early morning oil check show ANY loss. Total mileage on the car is now 198,888. I may be a new fan of synthetics but only more miles will tell for sure. I'll post an update in a few more weeks. Meanwhile, I am running original brakes, on my 6th set of Ecopias, and finally had to replace the second HID and the 12V earlier this year. Otherwise, trouble and expense free other than routine maintenance. Best car I have ever owned and I bought my first one 62 years and at least 45 vehicles ago.
From what I've read (just recently), high mileage oils work by swelling rubber and plastic seals, valve stem guides example, tightening them up. One caution, once you start high mileage oil, don't switch back to a regular oil, for then the gaskets will shrink back, and then some.
driving really hard (fast) tends to burn a whole lot of oil.....this is from experience on my 2006. And I also had a great similar experience going to Mobil 1
I won't revert to dino oil in this lifetime. My wifes Avalon is up next. Thanks for the comment. I've always driven the Prius way too fast but when on the western interstates it's impossible to not run 80-85. Hard on a car designed to be an urban commuter.
