If i can put dex cool in a 1988 ford f150?

If i can put dex cool in a 1988 ford f150?

You shouldn't mix with what is already in there, but if you are starting with an empty system then it will work fine in there.

No. Your 1988 F150 needs green-colored engine coolant meeting Ford specification ESE-M97B44-A (Motorcraft® Premium Antifreeze/Coolant) - see the first source. It is very different from Dexcool.