Ranger 4WD V6-4.0L (2009)
Heater Core: Testing and Inspection
Heater Core - Plugged
Climate Control System
Component Tests
Heater Core - Plugged
WARNING: Before disconnecting any heater water hoses, shut OFF the engine and wait until engine is fully cool. Failure to comply with this
warning may result in serious injury or burns from hot liquid escaping from the engine cooling system.
1. Check to see that the engine coolant is at the correct level.
2. Start the engine and turn on the heater.
3. When the engine coolant reaches operating temperature, feel the heater core inlet and outlet hoses to see if they are hot.
4. If the outlet only is not hot:
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the heater core may have an air pocket.
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the heater core may be plugged.
5. If the inlet only is not hot, the thermostat may not be working correctly.
