Engine Cooling

The cooling system components are the following:

• Cylinder head temperature (CHT) sensor
• Radiator
• Pressure relief cap
• Degas bottle
• Radiator draincock
• Coolant pump
• Thermostat
• Dual speed fan motor
• Resistor assembly
• Coolant hoses

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.

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

NOTE: The addition of Cooling System Stop Leak Pellets or equivalent meeting Ford specification WSS-M99B37-B6 darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan.
• Add Motorcraft Premium Gold Engine Coolant or equivalent meeting Ford Specification WSS-M97B51-A1 (yellow color). Do not mix coolant types.
• Do not add/mix orange-colored Motorcraft Specialty Orange Engine Coolant or equivalent meeting Ford specification WSS-M97B44-D or green colored Motorcraft Premium Engine Coolant meeting Ford specification ESE-M97B44-A or equivalent. Mixing coolants may degrade the coolant's corrosion protection.
• 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 unless it meets the requirements of Ford specification WSS-M97B51-A1. Not all coolant recycling processes meet this Ford specification. Use of such a coolant may harm the engine and cooling system components. Do not mix coolant types.

Fig 1: Coolant Flow Diagram, 3.9L and 4.2L

Courtesy of FORD MOTOR CO.