Visual Inspection and Diagnostic Pre-checks
PINPOINT TEST F : INSUFFICIENT, ERRATIC OR NO HEAT
F1 CHECK FOR CORRECT ENGINE COOLANT LEVEL
Ignition OFF. Check the engine coolant level.
Is the engine coolant at the correct level as indicated on the engine coolant recovery reservoir?
Yes | GO to F3 | |
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No | GO to F2 | |
F2 CHECK THE ENGINE COOLING SYSTEM FOR LEAKS
Pressure test the cooling system for leaks. Refer to the appropriate section in Group 303 for the procedure..
Does the engine cooling system leak?
Yes | REPAIR the engine coolant leak. Refer to the appropriate section in Group 303 for the procedure. TEST the system for normal operation. | |
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No | FILL and BLEED the cooling system. Refer to the appropriate section in Group 303 for the procedure. After filling and bleeding the cooling system, GO to F3 | |
F3 CHECK FOR COOLANT FLOW TO THE HEATER CORE
Run the motor until it reaches normal operating temperature. Select the floor position on the control assembly. Set the temperature control to full warm and the blower to the lowest setting. Increase engine speed to 3,500 RPM and hold for 30 seconds. Allow the engine to idle for 30 seconds. Using a suitable temperature measuring device, check the heater core inlet hose to see if it is hot.
Is the heater core inlet hose hot?
Yes | GO to F4 | |
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No | BLEED the cooling system per the cooling system draining and vacuum filling general procedure. Refer to the appropriate section in Group 303 for the procedure. After bleeding the cooling system, GO to F4 | |
F4 CHECK FOR A PLUGGED OR RESTRICTED HEATER CORE
Using a suitable temperature measuring device, measure the heater core outlet hose temperature.
Is the heater core outlet hose temperature similar to the inlet hose temperature (within approximately 6-17°C [10-30°F])?
Yes | DIAGNOSE for a blend door actuator not operating correctly. For inadequate temperature, GO to Pinpoint Test I |
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2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.