Originally Posted by 1993bonnie
! i CHECKED THE HEATER CORE HOSE AND ONE WAS WAMER THAN THE OTHER SO I GUESS THAT IS OK.
Maybe not. I just made a few tests on my '95 to make sure I was not leading you astray. I have a good heater core and am running a drilled 180 degree thermostat.
Check for airflow: Turn heater control to full hot; turn function to hot feet; turn fan on low, put hand on floor by heater duct outlet. Increase fan speed and determine if more air is flowing at each higher setting. If the airflow is poor at all the settings, you either have a ducting problem or very dirty fins on the air side of your heater core. If the airflow increases normally but the air is cold, do the next tests.
BE CAREFUL that you keep your hands clear of the alternator blades, pulley and belt! Tie back your hair, roll up your sleeves and take off your watch so stuff won't get caught in pulleys.
Condition A: With the engine fully warmed up (temp gauge showing about 180 on my car) heat control is turned to full hot; fan is on the lowest setting; heater function set to hot feet. Result: the top hose out of the tensioner assembly feeding the heater core is hot, return hose is hot too, maybe just a little bit cooler than the top hose.
Condition B: engine fully warmed up; heat control to full hot; heater function set to hot feet; fan on highest setting; Result: top hose hot; return hose becomes noticeably cooler than feed hose, but is still warm.
If you test under condition A and return hose never gets warm, that tells you the coolant is not flowing freely through the heater core and you probably need to change the heater core.
The temperature of the air coming through the heater core in the car won't be any warmer than the coolest hose you feel. If that return hose is not hot, the heater won't blow hot either.
Now there can be one more issue. If you changed the thermostat, are you sure that you bled all the air from the system using the little screw on top of the thermostat housing?