I have painted several cars and done body work but never tried to repair clear coat on a car. I have a friend that has a black car and the clear coat is starting to break down on his hood. It is milky looking in a spot that covers an area that is maybe 12 to 15 inches total. There is no flaking that I can see or spots where I can feel an edge . Should I sand whole hood and put new base coat on it or will sanding and just putting new clear on it be ok ? Would all the clear have to be sanded off or just problem area ? I know the whole hood would have to be sanded for new clear to stick . If just putting new clear on it would fix it what grit sandpapers should be used before shooting new clear on it ?
Thanks for any advice you guys may give me. This site has helped me so many times when I ask about other things I know someone can tell me the proper way for the fix to last.

hard to say,

but if i was painting it i would strip it

I agree that's the proper way to fix the problem. probably soon to come will be other spots just like the hood.
Jay D.