Peeling paint

I have had peeling paint on two vehicles a 2005 Mercury Grand Marquis White. Most of the peeling is the roof, the hood and the trunk lid. The paint separates from the primer coat, not from the bare metal. And those areas also get the most sunshine ,,,it's hot. My other peeling paint vehicle is a 2000 Dodge Ram van. Same top coat peels and the timer stays. As far as the Dodge Ram , Chrysler was trying to use waterborne paint on their vehicles. I do not know if the paint on the Mercury Marquis Is waterborne or not. Both vehicles are prone to mildew going on them. The mildew feeds on the paint I will I will be repainting my Mercury Grand Marquis soon. It is a wonderful car in all other aspects.