i added 5 quarts in one time by accident because i thought i was on my 4th. i checked the dipstick and it was a little over the top hole, but i drove around in it with no problems. my car burns oil anyway because i beat the car so i dont think it will affect it in a negative way. i think it just has more lubricant than it needs, which isnt necessarily a bad thing i think. im more afraid if i dont have enough oil. i once drained the car and only 2.5 quarts came out....