Cadillac Repair: heating, radiator fluid, mech shop

Question
oki bought this 92 cadillac sedan deville it runs good except the heating is not working the way it should the foermer owner replaced the thermostat and heater core at a mech. shop yet it still does not work properly the radiator  fluid is good half and half the recommended  amount what acn i do about this any suggestions
thanks tony

Answer
Are both heater hoses hot to the touch at normal operating temp ?.

Remove the glove box liner and you will see a metal rod about 4" long attached to a plastic arm via a clip connector. Change your system from full heat to full cold and watch this metal rod as is should move back and forth about 3" smoothly and quietly. Does it ?.