There is no such thing as protecting your car from flood damage. If it gets flooded it will be trashed no matter what you do. Most flooded cars are sold for parts or scrap, or dried and resold to unsuspecting customers (which will be big business this year -- and should make all used car buyers beware of low prices). You only have two options. Move your car to higher ground (or man made ground), or pray. I usually put my bets on the former.