Cooling System: Description and Operation

Engine Cooling

CAUTION: All vehicles are filled with Motorcraft Premium Gold Engine Coolant. Always fill the cooling system with the same type of coolant that was drained from the system. Do not mix coolant types.

The engine cooling system consists of the:
^ block heater.
^ fan blade and clutch.
^ fan shroud.
^ coolant expansion tank.
^ thermostat.
^ thermostat housing assembly (4.0L SOHC).
^ coolant pump.
^ radiator.
^ radiator cap.
^ radiator hose.
^ heater tube assembly.

The electronically controlled fan clutch is controlled by the powertrain control module (PCM) based upon requests for airflow to cool the engine, transmission and A/C condenser. If no cooling is required, the electronics permit the fan to spin at a slower speed yielding improved fuel economy.

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 coolant expansion tank.

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 Premium Gold Engine Coolant. Use the same coolant that is present in the system. Do not mix coolant types.
^ Do not add orange-colored Motorcraft Specialty Orange Engine Coolant. Mixing coolants may degrade the coolant's protection rating.
^ Do not add alcohol or methanol 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.
^ The addition of Cooling System Stop Leak Pellets darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan.

Note: Black Arrows Indicate Hot, White Arrows Indicate Cold.:

Coolant Flow Diagram, 4.0 SOHC Without Oil Cooler and Without Auxiliary Heater

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

Note: Black Arrows Indicate Hot, White Arrows Indicate Cold.:

Coolant Flow Diagram 4.0L SOHC With Oil Cooler and Without Auxiliary Heater

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

Note: Black Arrows Indicate Hot, White Arrows Indicate Cold.:

Coolant Flow Diagram 4.0L SOHC Without Oil Cooler and With Rear Heater

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

Note: Black Arrows Indicate Hot, White Arrows Indicate Cold.:

Coolant Flow Diagram 4.0L SOHC With Oil Cooler and With Auxiliary Heater

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

Note: Black Arrows Indicate Hot, White Arrows Indicate Cold.:

Coolant Flow Diagram 4.6L (3V) Without Auxiliary Heater

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

Note: Black Arrows Indicate Hot, White Arrows Indicate Cold.:

Coolant Flow Diagram 4.6L (3V) With Auxiliary Heater

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