why wont my heat work in my 91 buick skylark? on 1991 Buick Skylark

i have replaced the water-pump,thermostat,heater core ,radiator,heating sensors,heater control module and a new radiator cap but still no heat what could this be .its not the blower it blows strong but only cold air and the car doesnt over heat

1 answer
Hot water obviously isn't reaching the heater core.Sounds like it's related to a valve or you have an air lock somewhere.