Going on vacation, what am I gonna do with my car?

I live in AZ. im going on vacation to new york for 2 weeks. i live with my dad and the a/c in his car doesnt work, so hes gonna want to use my car when im gone.im one of those people that are overprotective of their cars. i dont want him(or any 1 else using my car) im 18 and the cars in my name. do i have to let him use it? because just the thought of it irritates me. he doesnt take care of his car thats why its all nasty and always breaking down so i dont want him driving mine. Yea i know i sound like a whiney brat, but my cars my baby. i worked hard to earn the money for it.