I have researched this to no end.....OIL. FWIW i have a 93 Civic with 280,000 miles on it that burns 1 qt every 1000 miles. I have not changed oil in it for 55,000 miles. I DO change the filter every 6-10,000 though. List of oils I have used for top offs. USED 20w50 motorcycle oil, USED 5w20...