Auto body repair & detailing: Cracked paint, cracked paint, uphill battle

Question
I have a 3 inch long crack in the paint of 2003 Yukon probably due to hitting the edge of the door.  Is there anything to prevent the crack ultimately chipping off (which will require the whole door painted). Will paint sealant forestall the inevitable?

Answer
You are fighting an uphill battle here, but with the galvonized steel underneath the paint, I forsee it taking a couple years or so before you really notice any paint degredation leading to chipping off of the finish, I would leave it be, and keep tha area waxed. Bill