I changed the engine oil this weekend and put in the normal 7 quarts. After warming the engine today I checked the level and it showed on the low side. So I added the rest of the gallon jug for a total of 8 quarts. The dipstick now shows just below the high mark. Maybe the AMSoil 0w-30 synthetic doesn't expand as much when warm as conventional oil does? It's not like that dinky little oil filter from AMSoil is any different in size than the OEM filter. I don't know where it's all going. I do let the old oil drip out for a good 15 minutes but that can't make more than a half cup of difference.