i have noticed that if i go more than 3mos or 3000mi the car burns a bit of oil, and that consumption increases the longer i put off the oil change. if i go only 3mos/3000 it doesn't burn any. on the other hand i have never used synthetic oil. running dino chevron delo 400 15/40.
no problem in winter and great mileage. oh and a great price too..
end of my .02
