Heater Performance Test

WARNING: This page is about a different car, the 2001 Dodge Grand Caravan and 2001 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.

Check engine coolant level, drive belt condition and tension, airflow across radiator, radiator hoses and cooling fan operation. Repair any faults with cooling system, as necessary. Start engine and allow it warm up to normal operating temperature, go to next step.
With engine idling at normal operating temperature, set A/C heater controls as follows. Temperature control lever(s) to full hot. Mode selector dial to floor position. Blower speed on highest setting. Using a test thermometer, check air temperature from floor vent outlets. Compare floor outlet temperature with ambient temperature. See HEATER SYSTEM PERFORMANCE table. If readings are comparable, heater system is operating as designed. If readings are not correct, go to next step.

Check for possible cause of poor coolant flow to heater core. Check that both heater hoses are hot or warm to touch, and ensure coolant is flowing through heater core. Check for pinched or kinked heater hoses. Check for improper heater hose routing. Check for obstructed cowl inlet grille or restricted air intake to heater plenum. Check operation of all A/C-heater outlet mode doors and actuators. Correct any faults present.

HEATER SYSTEM PERFORMANCE

Ambient Temp. - °F (°C)	Floor Outlet Temp. - °F (°C)
60 (15.5)	144 (62.2)
70 (21.1)	147 (63.8)
80 (26.6)	150 (65.5)
90 (32.2)	153 (67.2)