Maximum Heater Output: Test And Action
Engine coolant is provided to the heater system by two heater hoses. With the engine idling at normal operating temperature, set the temperature control to maximum heat, the mode control to the floor position, and the blower in the highest speed position. Using a test thermometer, check the temperature of the air being discharged from the floor outlets. Compare the test thermometer reading to the Heater Temperature Reference chart.
| Ambient Air Temperature | 15.5° C (60° F) |
21.1° C (70° F) |
26.6° C (80° F) |
32.2° C (90° F) |
| Minimum Air Temperature at Floor Outlet | 52.2° C (126° F) |
56.1° C (133° F) |
59.4° C (139° F) |
62.2° C (144° F) |
If the floor outlet air temperature is insufficient, check that the cooling system is operating to specifications (Refer to COOLING ). Both heater hoses should be HOT to the touch (the coolant return hose should be slightly cooler than the supply hose). If the coolant return hose is much cooler than the supply hose, locate and repair the engine coolant flow obstruction in heater system.