The system is filled with ethylene glycol based liquid (antifreeze), non-freezing at ambient temperatures down to -40°C.
NOTE: The procedure for replacing the coolant is described in the subsection "Replacing the coolant", page 101.
WARNINGS: It is not recommended to fill the cooling system with water, since the antifreeze contains anti-corrosion, anti-foaming and anti-scale additives.
Coolant is toxic! Avoid inhaling its vapors and getting it on your skin. Promptly eliminate any leaks in the cooling system to prevent coolant vapors from getting into the car's interior during operation. Your health is more valuable than a new cooling system hose or a tube of sealant!
The normal thermal mode of the engine is determined by the temperature of the coolant, which is maintained automatically by a thermostat in the range of 90-100°C.
Radiator with horizontal fluid flow, with a tubular-ribbon aluminum core and plastic tanks. At the bottom of the right tank is a drain cock. The radiator tanks contain the supply and discharge hose pipes to the engine water jacket, as well as a hose pipe connecting the radiator to the expansion tank. On cars with automatic transmission, a heat exchanger is built into the radiator to cool the gearbox working fluid.
Expansion tank serves to compensate for the changing volume of the coolant depending on its temperature. The tank is made of translucent plastic. Two arrows are applied to its wall to control the coolant level, and a filler neck is located on top, hermetically sealed with a plastic plug with two valves inside (inlet and outlet), assembled in a single block. The outlet valve opens at a pressure of 140-150 kPa (1.4-1.5 kgf/cm²), ensuring an increase in the boiling point of the coolant and preventing intensive vaporization. When the liquid cools, its volume decreases and a vacuum is created in the system. The inlet valve in the plug opens at a vacuum of about 3 kPa (0.03 kgf/cm²) and allows air to pass into the expansion tank.
NOTE: Proper operation of the plug valves is very important for the proper operation of the cooling system, but often when problems occur (boiling of coolant, etc.) car enthusiasts pay attention only to the operation of the thermostat, forgetting to check the valves. A leaky exhaust valve leads to a decrease in the boiling point of the coolant, and its jamming in the closed state leads to an emergency increase in pressure in the system, which can cause damage to the radiator and hoses.
Water pump centrifugal type provides forced circulation of liquid in the cooling system, is installed on the front surface of the cylinder block and is driven by a poly V-belt of the auxiliary drive. The pump has sealed bearings that do not require replenishment of lubricant. The pump is not subject to repair, in case of failure (fluid leak or bearing damage) it is replaced as a whole.
Thermostat with a solid heat-sensitive filler is installed on the water distributor. The thermostat maintains the normal operating temperature of the coolant and reduces the engine warm-up time. An electric heating element is built into the thermostat, which, upon command from the electronic engine control unit, heats the filler, reducing the thermostat opening temperature if necessary.
In partial engine load mode, no voltage is supplied to the heating element, the thermostat is completely closed at a coolant temperature of up to 105°C. In this case, the liquid circulates along a small circuit, bypassing the radiator, which accelerates engine warm-up. At a temperature of 105°C, the thermostat begins to open, and at 120°C it opens completely, ensuring circulation of liquid through the radiator.
In full engine load mode, the heating element is switched on and the thermostat opening temperature drops to 90°C.
Water distributor, in the plastic housing of which the coolant temperature sensor is located, is installed on the rear end of the cylinder head. The water distribution pipe and the heater radiator hoses are connected to the water distributor.
Electric fan with a plastic nine-blade asymmetric impeller provides air blowing through the radiator at low vehicle speeds, mainly in urban conditions or on mountain roads, when the oncoming air flow is insufficient to cool the radiator.
To improve the efficiency of the fan, it is installed in a casing and attached to it at three points through rubber pads. The casing, in turn, is attached to the radiator at four points.
The electric fan is controlled by the engine control unit, which receives information about the coolant temperature from the coolant temperature sensor located in the water distributor.
In addition to the listed elements, the system includes an engine cooling jacket surrounding the cylinder walls in the block, combustion chambers and gas channels in the cylinder head. In addition, the interior heater radiator is included in the cooling system via hoses.
[Information taken from the official website: «CHEVYMAN»]