Coolant is coolant no matter what brand it is, the only difference could be it was either pure or premixed (half water) OR its long life coolant which is red in colour.
About the problems, welcome to the 15-year-old-plus car owners club.
my car is an 89 and yeah, this is about the time when all those 15yr old parts start to go.
Have you ever replaced your fuel filter, air filter, spark plugs, wires, cap and rotor, etc. What about your timing belt? mine is ready to go soon and I know my car is dieseling a bit because of this. timing seems to be off. Play around with the carburator, maybe you need to adjust the idling.
What about the rad? is it the original rad? if it is, then you're probably way overdue for a new replacement. Push on the rad fins, if they break off like you're touching paper, then you need a new rad.
