i think at walmart they sale 4 quarts and 5 in gallon jugs my moms van sais 4/5 but i end up using a gallon. you may want to take valvcovers off and make sure port holes are open you cand do this by a good piece of wire threw them. but like i say about my moms car. but to me the 5 quart gallon arn't realy a gallon.