Cooling System: Description and Operation

Engine Cooling

NOTICE: Vehicle cooling systems are filled with Motorcraft(R) Specialty Orange Engine 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. Cooling System Flushing

NOTE: During normal vehicle operation, Motorcraft(R) Specialty Orange Engine 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.

The cooling system consists of the following components:

- Block heater (located in the thermostat housing for 3.5L GTDI and 3.7L engines, the LH front of the 5.0L engine cylinder block and the LH rear of the 6.2L engine cylinder block.)
- Coolant expansion tank (6.2L engine)
- Degas bottle (3.5L GTDI, 3.7L and 5.0L engines)
- Electric cooling fan and shroud assembly
- Radiator
- Pressure relief cap (located on the radiator for the 6.2L engine and on the degas bottle for the 3.5L GTDI, 3.7L and 5.0L engines)
- Radiator draincock (located in the RH corner of the radiator)
- Upper and lower radiator hoses
- Coolant pump
- Coolant thermostat

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 degas bottle.

When adding engine coolant, use a 50/50 mixture of engine coolant and distilled water. A coolant concentration of 50% will provide freeze point protection down to -37°C (-34°F).

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

- Add Motorcraft(R) Specialty Orange Engine Coolant or equivalent.
- Do not add/mix any other engine coolant. Mixing coolants may degrade the coolant's corrosion protection.
- Do not add alcohol, methanol, 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 coolants may harm the engine and cooling system components. Do not mix coolant types.

Coolant Flow Diagram, 3.5L GTDI

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









Coolant Flow Diagram, 3.7L

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









Coolant Flow Diagram, 5.0L

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









Coolant Flow Diagram, 6.2L

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