PINPOINT TEST B : The Engine Overheats: Notes

Normal Operation and Fault Conditions

The engine cooling system maintains the engine temperature during operation. Correct coolant flow through the engine, radiator and remainder of cooling system passages and components is essential to maintaining a correct engine temperature.

Engine coolant flows primarily from the engine to the radiator circuit and back to the coolant pump. Coolant is sent from the coolant pump through the engine block and cylinder heads. A separate circuit from the engine also feeds the heater core with coolant. The coolant pump circulates the coolant. For 2.0L GTDI, the coolant pump operated by engine rotation through the accessory drive belt pulley. For 3.5L Ti-VCT and 3.5L GTDI, the coolant pump is operated by engine rotation through the timing chain sprocket. The coolant thermostat is a control valve actuated by coolant temperature. When the thermostat is closed, coolant flow bypasses the radiator circuit and returns to the coolant pump. When the thermostat is opened, coolant flows through the radiator circuit to transfer engine-generated heat to the outside air.

Engine overheating generally occurs when there is a disruption in the ability to control either coolant flow at the correct rate, the inability to transfer heat from the engine through the coolant (including low coolant) or an inability to transfer engine-generated heat to the outside air through the radiator. Engine overheating can be attributed to:

Low coolant level
External engine coolant leak
Airlock in system
Pressure relief cap installation
Restricted airflow through the A/C condenser/radiator
Internal engine coolant leak
Coolant condition/concentration
Accessory drive components
Non-Original Equipment Manufacturer (OEM) engine enhancement components
Electric cooling fan
Radiator
Thermostat
Temperature gauge
Coolant pump
Coolant flow restriction

Refer to Engine Cooling , System Diagram.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Conditions
P0217	Engine Coolant Overtemperature Condition	Indicates an engine overheat condition was sensed by the CHT sensor or the ECT sensor.
P1285	Cylinder Head Overtemperature Condition	Indicates an engine overheat condition was sensed by the CHT sensor or the ECT sensor.
P1299	Cylinder Head Overtemperature Protection Active	Indicates an engine overheat condition was detected by the CHT sensor or the ECT sensor. A failure mode effects management strategy called fail-safe cooling was activated to cool the engine.

NOTE: The cooling system is filled with Motorcraft® Orange Antifreeze/Coolant. Always fill the cooling system with the manufacturer's specified coolant. If a non-specified coolant has been used the cooling system must be chemically flushed. Refer to Cooling System Flushing . Failure to follow these instructions may damage the engine or cooling system.

NOTE: Use Motorcraft® Orange Antifreeze/Coolant. Use the same type of coolant originally used to fill the cooling system. Do not mix coolant types. Mixing coolant types degrades the coolant corrosion protection and may damage the engine or cooling system.

NOTE: During normal vehicle operation, Motorcraft® Orange Antifreeze/Coolant may change color from orange to pink or light red. As long as the engine coolant is clear and uncontaminated, this color change does not indicate the engine coolant has degraded nor does it require the engine coolant to be drained, the system to be flushed, or the engine coolant to be replaced.