Ford Mustang (1993-2004) Service Manual: Water Pump - 3.8L

Engine Cooling (Description and Operation)

CAUTION: Vehicle cooling systems 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 4.6L cooling system components include the:

• block heater
• engine coolant temperature (ECT) sensor
• fan blade, fan motor and fan shroud assembly
• radiator
• pressure relief cap
• radiator draincock
• coolant pump
• coolant thermostat
• oil filter adapter
• radiator overflow hose
• upper radiator hose
• lower radiator hose

The radiator overflow hose circulates the coolant.

The coolant thermostat:

• controls the engine coolant temperature.
• allows for quicker engine warm-up.

The degas bottle/coolant expansion tank:

• provides a location for service fill.
• contains coolant expansion and system pressurization.
• provides air separation during operation.
• replenishes the engine coolant to the system.

The engine coolant flows:

• from the lower radiator hose to the coolant pump.
• from the coolant pump to the engine block and the cylinder heads.

The 3.8L cooling system components include the:

• block heater
• engine coolant temperature (ECT) sensor
• fan blade, fan motor and fan shroud assembly
• radiator
• radiator cap
• radiator draincock
• coolant pump
• coolant thermostat
• oil filter adapter
• radiator overflow hose
• coolant expansion tank
• upper radiator hose
• lower radiator hose

The fan blade draws air through the radiator to help cool the engine coolant.

The fan motor:

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

The engine coolant:

• flows through the radiator tubes and is cooled by passing air over the cooling fins.
• is then circulated from the radiator outlet tank through the coolant pump and into the cylinder block to complete the circuit.

A closed coolant thermostat returns the engine coolant to the coolant pump. An open coolant thermostat allows the engine coolant to flow to the radiator.

CAUTION: 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 (4.6L) or coolant expansion tank (3.8L).

When adding engine coolant, use a 50/50 mixture of engine coolant and deionized water.

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 Gold Engine Coolant VC-7-A (in Oregon VC-7-B) or equivalent meeting Ford specification WSS-M97B51-A1 (yellow color). Use the same coolant that is present in the cooling system. Do not mix coolant types.

Do not add/mix orange-colored Motorcraft Speciality Orange Engine Coolant VC-2 or equivalent 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 WSSM97B51- A1. Not all coolant recycling processes meet these Ford specifications. Use of such coolants can harm the engine and cooling system components.

The coolant temperature sensor (4.6L) or cylinder head temperature sensor (3.8L) provides a signal to the temperature gauge.

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.