Cooling System: Description and Operation

Engine Cooling

CAUTION: Some vehicle cooling systems are filled with Motorcraft Premium Engine Coolant VC4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specification ESE-M97B44-A (green color). Others are Filled with Motorcraft Premium Gold Engine Coolant VC-7-A (in Oregon VC-7-B) or equivalent meeting Ford specification WSS-M97B51-A1 (yellow color). Always fill the cooling system with the same coolant that is present in the system. Do not mix coolant types.
NOTE: The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6, darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan.

The cooling system components are:
- engine coolant temperature sensor (ECT sensor)
- radiator
- degas bottle
- radiator draincock
- water pump
- water temperature indicator sender unit
- water thermostat
- three speed fan motor assembly
- fan braking relay
- resistor relay
- HEDF relay
- EDF relay
The water pump circulates the coolant.
The water thermostat:
- controls the engine coolant temperature.
- allows quicker engine warm-up.
The degas bottle:
- provides a location for fill.
- contains coolant expansion and system pressurization.
- provides air separation during operation.
- replenishes the engine coolant to the system.
The fan motor:
- operates only when the ignition switch is in the RUN position.
- has three speeds and is controlled by four relays.
The engine coolant flows:
- from the lower radiator hose to the water pump.
- from the water pump to the engine block and the cylinder heads.
A closed water thermostat returns the engine coolant to the water pump; an open water thermostat allows the engine coolant to flow to the radiator. 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 proper concentration and fluid level in the degas bottle.
When adding engine coolant, use a 50/50 mixture of clean drinkable water and engine coolant.
To maintain the integrity of the coolant and the cooling system:

NOTE: The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6, darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan. Add Motorcraft Premium Engine Coolant VC-4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specification ESE-M97B44-A (green color), or Motorcraft Premium Gold Engine Coolant VC-7-A (in Oregon VC-7-B) 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 VC-2 meeting Ford specification WSS-M97B44-D. 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 ESE-M97B44 A or WSS-M97B51-A1. Not all coolant recycling processes meet these Ford specifications. Use of such coolants can harm the engine and cooling system components.