I was in your class in Montpelier Vt. at Autocraftsman. We had the discussion about 4 quarts of oil in a Prius. This last week I had one of my regulars in and opened up the throttle plate to check for oil. You win 4 quarts is to much. It had oil in the intake. 3.7 quarts ftom now on. Thanks for the tip and alot of good information.