My Zetec holds 4.5 qts, but I put in 5 qts...If you take a hard right turn with the RPM's high it could cause oil starvation, which will/can make your engine go BOOOOOOOM! Put in a 1/2 qt more than it holds, you should be alright. I know a guy around here that puts 7 qts in his 98 SE Duratec, and the car is still running.