My car takes for ever to start blowing warm air from the heater. on 1991 Lexus LS400

Fluid levels are good in the radiator, water pump seems to be working fine, fluids ae being circulated. Dont know where to start from here. Heater core is not leaking.

Asked by for the 1991 Lexus LS400
sounds like you need a t stat
1 more answer
maybe the heater core is clogged