Heater System Performance
- Check coolant level, drive belt tension, vacuum line connections, radiator airflow, and cooling fan operation. With transmission in Park or Neutral, start engine. Allow engine to reach normal operating temperature. With engine at idle, set controls to maximum heat, floor and high blower positions. Using a thermometer, check air temperature coming from floor vents. See HEATER OUTPUT TEMPERATURE table.
- If floor outlet air temperature is lower than specified, check cooling system and electric cooling fan. See ELECTRIC COOLING FANS - ALL OTHER MODELS article.
- Check that both return and supply heater hoses are hot. If coolant return hose is much cooler than supply hose, repair coolant obstruction in heater system. Check for airflow obstruction in heater system. Check blend air door for proper operation.
HEATER OUTPUT TEMPERATURE
| Ambient Temp. - °F (°C) | Outlet Vent Temp. - °F (°C) |
|---|---|
| 60 (15.6) | 144 (62.2) |
| 70 (21.1) | 147 (63.8) |
| 80 (26.6) | 150 (65.5) |
| 90 (32.2) | 153 (67.2) |