Insufficient Heating (Without A/C)

Insufficient heating

Diagnostic Procedure:

1. Check the coolant level Testing and Inspection

2. Check the radiator cap Testing and Inspection

3. Check the coolant temperature during normal operation

4. Check the heater core inlet hose temperature:

5. If it is COLD, check for restrictions in the hose, a damaged or leaking thermostat, or a damaged or leaking water pump

6. If it is HOT, check for restrictions in the heater core. Back flush or replace the heater core

7. Check the operation of the air mix control cable and linkage Air Mix Control Cable Removal/Installation

8. Check the blower motor unit for obstructions

9. Check for air leaks around the ducts and vents

Also check for:

- Damaged cylinder head gasket