If you are going to change your oil, why not change all of it? There is more than 24oz. of old oil left in the engine which mixes with the fresh oil upon start up and discolors the fresh oil quickly, so when you mix 24oz. of old oil with 96oz. of fresh oil the breakdown starts immediately.
Rogue Chopper has the fix for this problem; the Scavenger Total Oil Change System. This clever yet easy to use system effectively purges all the oil from the engine when performing an oil change. With this system there is no contaminated oil mixing with new oil so it stays fresh longer.