I have a 1991 Trail Boss 350 4×4. The reservoir for the coolant is cracked. Getting a new one or one that isn’t damaged may not be possible. So, what are my options?

If I just leave it, the rad will drain off and then not have sufficient coolant while running.

I have a 1991 Trail Boss 350 4×4. The reservoir for the coolant is cracked. Getting a new one or one that isn’t damaged may not be possible. So, what are my options?

If I just leave it, the rad will drain off and then not have sufficient coolant while running.