Engine Cooling: Notes

NOTE: The engine cooling system is filled with Motorcraft ® 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 in this service information. Failure to follow these instructions may damage the engine or cooling system.

NOTE: During normal vehicle operation, Motorcraft® 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 components include the:

block heater (if equipped)
Cylinder Head Temperature (CHT) sensor
fan motor and shroud assembly
radiator
radiator cap
radiator draincock
coolant pump
coolant thermostat
oil filter adapter (5.4L engine)
oil cooler (5.4L engine)
radiator overflow hose
degas bottle
upper radiator hose
lower radiator hose
Engine Coolant Temperature (ECT) sensor (5.4L engine)

Fig 1: Locating Weep Hole

Courtesy of FORD MOTOR CO.

The 3.7L timing chain gear is located under the engine front cover mounted to the block and has a gasket and dynamic mechanical seal. If the dynamic mechanical seal fails, coolant will leak from the weep hole. A weep hole is provided on the front left side of the engine behind the generator. This weep hole create a reservoir for normal coolant seepage and evaporation. Every timing chain gear will have some leakage past the dynamic mechanical seal. Dampness and crusting around the weep hole is acceptable and an expected result of normal engine operation. Coolant spray or leakage amounts great enough to puddle should be addressed.

The 3.7L and 5.0L engines use a cold side thermostat. This means the thermostat controls the flow of cooled radiator coolant into the warmer engine cooling circuit. The thermostat is located at the lower radiator hose connection to the engine. During initial warm-up, the engine coolant increases in temperature, causing the thermostat to open. The cooler coolant from the radiator mixes with the warm engine coolant, causing the thermostat to close. The thermostat opens and closes several times before the engine coolant is warm enough to allow the thermostat to remain open. The engine must run much longer than a vehicle with a hot side thermostat before the thermostat remains fully opened.

The 5.4L engine uses a typical hot side thermostat.

The fan motor:

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

Engine coolant provides boil protection, corrosion protection, freeze protection and cooling efficiency to the engine and cooling components. In order to obtain these protections, maintain the engine coolant 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® Specialty Orange Engine Coolant or equivalent (orange color) meeting Ford specification WSS-M97B44-D. Do not mix coolant types.
do not add or mix with any other engine coolant. Mixing coolants may degrade the coolant 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.
Ford Motor Company does NOT recommend the use of recycled engine coolant in vehicles originally equipped with Motorcraft® Specialty Orange Engine Coolant since a Ford-approved recycling process is not yet available.

The optional block heater:

electrical heating element is installed in the core plug opening.
uses a standard 110V electrical supply.
keeps the engine coolant warm during cold weather.