I have a 2002 Corolla with 40K and last oil change (37500) I switched to M1 5w-30 Synthetic Oil. The other night I saw the oil light come on and I popped the hood and checked the oil...it didn't even register on the dipstick. There was only 3500 miles on the oil but since it was so low I just decided to do an Oil Change with the filter. Man was it dirty!! My 4-runner has about 6K on the M1 and it is still full and the oil is still a bronze color. My question is: Where did the oil go. I don't seem to be burning oil and I never had this problem with Dino oil. Any clues to what may be wrong?