Cooling System: Description and Operation

Engine Cooling

NOTICE: Vehicle cooling systems are filled with Motorcraft(R) Premium Gold Engine Coolant (yellow color). Always fill the cooling system with the same type of coolant that was drained from the system. Do not mix coolant types. Mixing coolant types degrades the corrosion protection of Motorcraft(R) Premium Gold Engine Coolant, and may result in damage to the cooling system.

The cooling system consists of the following components:

- Block heater (located in the lower LH corner of the cylinder block)
- Coolant crossover manifold assembly - 4.6L (2V), 4.6L (3V) and 5.4L (3V) only (located in front of the intake)
- Coolant expansion tank
- Electric cooling fan and shroud assembly
- Radiator
- Pressure relief cap (located on the radiator)
- Radiator draincock (located in the RH corner of the radiator)
- Upper and lower radiator hoses
- Coolant pump
- Coolant thermostat

The block heater:

- warms the coolant during extreme cold weather conditions.
- uses 110V AC electrical source.

The coolant crossover manifold:

- provides for coolant flow between the cylinder heads.
- houses the thermostat.
- has an attachment for the heater hose.

The coolant expansion tank:

- holds surplus coolant when hot.
- allows coolant expansion.
- replenishes coolant to the system.

The fan motor:

- operates only when the ignition switch is in the RUN position.
- will not operate with the ignition switch in the OFF position.

The radiator:

- allows excess heat to be transferred to the air.
- cannot be serviced. Install a new radiator.

The pressure relief cap:

- provides for cooling system pressurization.
- is the location for service fill.

The radiator draincock:

- provides for cooling system draining.

The radiator hoses:

- allow coolant flow between the engine and the radiator.

The coolant pump:

- circulates the coolant.

The coolant thermostat:

- controls coolant temperature.
- allows quicker engine warm-up.

The engine coolant flows:

- from the lower radiator hose to the coolant pump.
- from the coolant pump to the engine block, the cylinder heads, heater core and PCV fittings.

- thermostat closed, the coolant returns to the coolant pump.
- thermostat open, the coolant flows back to the radiator for heat rejection.

NOTICE: Engine coolant provides freeze protection, boil protection, cooling efficiency and corrosion protection to the engine and cooling components. In order to obtain these protections, the engine coolant must be maintained at the correct concentration and fluid level in the overflow bottle, or the engine may be damaged.

When adding engine coolant, use a 50/50 mixture of engine coolant and distilled water.

To maintain the integrity of the coolant and the cooling system:

- add Motorcraft(R) Premium Gold Engine Coolant (yellow color). Do not mix coolant types. Mixing coolants may degrade the coolant's protection rating.
- do not add alcohol, methanol or brine or any engine coolants mixed with alcohol or methanol antifreeze. These can cause engine damage from overheating or freezing.
- do not mix with recycled coolant. Use of such a coolant may harm the engine and cooling system components.

Coolant Flow Diagram, 4.6L (2V)

NOTE: Black arrows indicate hot, white arrows indicate cold.











Coolant Flow Diagram, 4.6L (3V)

NOTE: Black arrows indicate hot, white arrows indicate cold.











Coolant Flow Diagram, 5.4L (3V)

NOTE: Black arrows indicate hot, white arrows indicate cold.











Coolant Flow Diagram, 6.2L (2V)

NOTE: Black arrows indicate hot, white arrows indicate cold.