Cooling System: Description and Operation

The cooling system components are:
- block heater
- engine coolant temperature ECT sensor (5.4L 4V only)
- fan blade
- fan clutch
- fan shroud
- radiator
- radiator cap
- radiator coolant recovery reservoir
- radiator draincock
- water temperature indicator sender unit
- water thermostat and gasket assembly (4.2L)
- water thermostat(4.6L, 5.4L)
- upper radiator hose
- lower radiator hose

The water pump circulates the coolant.

The water thermostat:
- controls coolant temperature.
- allows quicker engine warm-up.

The degas bottle:
- holds surplus coolant when hot.
- de-aerates the system reducing engine hot spots.
- is the location for service fill.
- allows coolant expansion and system pressurization [110 kPa(16 psi)].
- provides a location for air separation during operation.
- replenishes coolant to the system.

The fan blade draws air through the radiator to help cool the system coolant.

The fan clutch is a thermostatic-controlled clutch that controls the fan drive.

Coolant flow is as follows:

The radiator allows excess heat to be transferred to the air.

- The radiator cannot be serviced. Install a new radiator.

The engine coolant flows:
- from the lower radiator hose to the water pump.
- from the water pump to the engine block and the cylinder heads.
+ Thermostat closed, the coolant returns to the water pump.
+ Thermostat open, the coolant flows back to the radiator.
- to the radiator for heat rejection then back to the lower radiator hose.

Recycled coolant: use recycled engine coolant produced by Ford approved processes. Not all coolant recycling processes produce coolant which meets Ford specification ESE-M97B44-A, and use of such a coolant may harm the engine and cooling system components.

Unsatisfactory coolant materials:
- Alcohol-type antifreeze does not provide adequate water pump lubrication.
+ has a lower boiling point
+ provides reduced antifreeze protection
- Alkaline brine solutions will cause serious engine cooling system damage.

The block heater:
- is an optional electrical heating element installed in core plug opening.
- uses a standard 110v electrical supply.
- keeps the engine coolant warm during cold weather.