94 V6 Mustang. Desperately seeking help...

Yup same for me. I have a 99 v6 auto. I had to replace the water pump around 86k, was having the heater problem too at that time. Fix refill and off to work i went in a warm car. Then i also had to replace my radiator about a month ago. It took a couple topping off's before the air was all gone, but at time the air cause my heater not to work too... id check for that like they said.