Contents: General description ↧ Radiator ↧ Expansion tank ↧ Coolant pump; Water pump ↧ Thermostat ↧ Cooling system fan ↧ With the air conditioner turned off… ↧ The air conditioner is on ↧
General description
The engine cooling system ensures that the engine temperature is maintained at an efficient level in all engine operating modes.
When the engine is cold, the cooling system cools the engine slowly or not at all. This slow cooling allows the engine to warm up quickly.
The cooling system includes a radiator and recirculation subsystem, cooling fans, thermostat and housing, water pump and water pump drive belt. Timing belts rotate the water pump.
For the cooling system to function, all components must work properly. The water pump draws coolant from the radiator. The coolant circulates through water jackets in the engine block, intake manifold, and cylinder head. When the coolant temperature reaches the thermostat's operating temperature, the thermostat opens. The coolant then returns to the radiator where it is cooled. The system directs some of the coolant through hoses to the heater core. This provides heating and defrosting. The expansion tank is connected to the radiator to receive the coolant displaced by the high temperature.
The expansion tank ensures the correct coolant level.
The cooling system of this engine does not have a radiator cap or filler neck. Coolant is added to the system through an expansion tank.
Radiator
This car has an aluminum radiator with a light-weight plate pipe. Plastic tanks are installed on the right and left sides of the radiator heat exchanger.
On vehicles with an automatic transmission with a final drive assembly, the transmission fluid cooling lines pass through the left radiator tank. The drain plug is located on this radiator. To drain the cooling system, open the drain plug.
Expansion tank
The expansion tank is a plastic container similar to a windshield washer reservoir.
The expansion tank is connected to the radiator by a hose, and the engine cooling system by another hose. When the car is running, the engine coolant heats up and expands. Some of the engine coolant displaced by this expansion flows from the radiator and engine into the expansion tank. Air in the radiator and engine is forced into the expansion tank.
After the engine is stopped, the coolant cools and compresses. The displaced engine coolant flows back into the radiator and engine. This maintains the required coolant level in the radiator and increases cooling efficiency.
Set the coolant level between the MIN and MAX marks on the expansion tank when the system is cold.
Coolant pump; Water pump
The belt-driven centrifugal coolant pump consists of an impeller, a drive shaft and a belt pulley. The coolant pump is mounted on the front of the transverse engine and is driven by the timing belt.
The impeller is on a sealed bearing. The coolant pump is serviced as a single unit and therefore cannot be disassembled.
Thermostat
The wax thermostat controls the flow of engine coolant through the engine cooling system. The thermostat is mounted on the thermostat housing on the front of the cylinder head.
The thermostat stops the flow of coolant from the engine to the radiator to ensure rapid heating and regulation of coolant temperature. The thermostat remains closed when the coolant temperature is low, preventing the engine coolant from circulating through the radiator. At this time, the engine coolant circulates only through the heat exchanger for rapid and uniform heating.
Once the engine warms up, the thermostat opens. This allows engine coolant to flow through the radiator, where heat is dissipated through the radiator. The opening and closing of the thermostat allows engine coolant to flow into the radiator and keep the engine temperature within the operating range.
The wax ball in the thermostat is hermetically sealed in a metal shell. The wax element of the thermostat expands when heated and contracts when cooled.
As the vehicle operates and the engine heats up, the coolant temperature increases. When the coolant temperature reaches a predetermined value, the wax element of the thermostat expands and presses against the metal shell, causing the valve to open. This allows engine coolant to flow through the engine cooling system and cool the engine. As the wax ball cools, its contraction allows the spring to close the valve.
The thermostat begins to open at 87°C (189°F) and is fully open at 102°C (216°F). The thermostat closes at 86°C (187°F).
Cooling system fan
Caution! To prevent injury, keep hands, tools, and clothing away from the cooling fan. The fan is electric and may turn on whether the engine is running or not.
Warning! If a fan blade is bent or damaged in any way, do not attempt to repair or reuse the damaged part. A bent or damaged fan must be replaced with a new one. Failure to do so may result in injury.
The cooling fans are installed behind the radiator in the engine compartment. The cooling system of this vehicle has two cooling fans - the main and auxiliary. Electric cooling fans increase the air flow through the radiator fins and through the condenser on vehicles equipped with air conditioning. This allows for faster cooling at idle or low speeds.
Cars with and without air conditioning have two fans in the casing. The size of the main fan is 340 mm (13.4 inches) in diameter with five blades, and the auxiliary one is 320 mm (12.6 inches) in diameter with seven blades. They help draw air through the radiator and condenser. Two fan motors, attached to the center of each fan on the assembled shroud, drive both fans.
With the air conditioner turned off or for a model without air conditioning
- The cooling fans are driven by the ECM via the series/parallel cooling fan relay.
- The ECM turns on the cooling fans at low speed when the coolant temperature reaches 96°C (205°F) and at high speed when the coolant temperature reaches 100°C (212°F).
- The ECM switches the cooling fans from high to low speed at 94°C (201°F) and turns them off at 90°C (194°F).
The air conditioner is on
- The ECM turns on the slow speed of the fans when the A/C system is on. The ECM switches to high speed of the fan when the coolant temperature reaches 118°C (244°F) or when the high side of the A/C pressure reaches 1760 kPa (255 psi).
- The cooling fans return to low speed when the coolant temperature reaches 115°C (239°F) and when the high side of the air conditioner reaches 1347 kPa (195 psi).