Ford dealership is having problems with heater core repair. 2002 Ford F150 Supercrew. Problem is antifreeze (or early on just smell) in the cabin. 4 heater core replacements in 2 years. A hose (?) replaced. Electrolysis kit replaced. 4th heater core replacment finished yesterday. I know that I need to let the dripped antifreeze work out of the system, but I am smelling mild antifreeze this AM. Usually gets worse over 2-3 days then I have to take it in. Anyone know what might be being missed here?