Heater Output Temperature Check

The heat output of the heater system can be checked with the following procedure.

Preparation
With the engine sufficiently cool, the radiator cap should be removed and the engine started and allowed to idle. Heater controls should be set to "HEATER" mode, full "HOT" temperature and "HIGH" blower speed. When coolant flow in the radiator is visible through the filler neck, the radiator cap should be installed.

Minimum Acceptable Heater Output Temperatures:

Temperature Check
When the engine is warmed up (after approximately 20 minutes of operation), the vehicle should be driven. Use an accurate thermometer to determine the temperature of the outside air and the temperature of the air discharged at the floor outlets with the vehicle being driven at 48 km/ha (30 mph). Minimum acceptable heater output temperatures at four different outside air temperatures are shown in the table.




Minimum acceptable heater output temperatures for outside air temperatures other than those shown can be approximated by using the Fahrenheit scale and rounding off the outside air temperature to the nearest 5 degrees. For every additional 5 degrees of outside temperature, an additional 1.8 degrees of heater output temperature should be allowed when the outside temperature is below 50 degrees. An additional 1.6 degrees of heater output temperature should be allowed for every 5 degrees of outside temperature when the outside temperature is above 50 degrees.