Maximizing your cooling system sales means selling more than belts and hoses: knowing the components that make up a system is a key part of ensuring that you don’t miss out on additional sales.
And if you are able to delve into the functioning of these compo- nents, it can also help you generate sales with the DIY customer, and the technician faced with a perplexing repair.
The Antifreeze/Coolant is the lifeblood of a vehicle’s cooling system.
The Radiator is designed to dissipate the heat that has been picked up by the coolant as circulated through the engine.
Coolant is circulated to and from the radiator via Rubber Hoses. These can suffer from a variety of ailments, but contrary to the “old days,” modern hoses don’t show outward signs of imminent failure. Some bulging or softness may signal a problem, but it can’t be counted on as a sure check. Cracks that work their way from the inside out can be a hidden threat to the integrity of the cooling system.
The Serpentine Belt systems may be charged with a variety of responsibilities: water pump, alternator, air conditioning compressor.
To perform these functions, the Tensioners must be operating properly. A professional counterperson must be vigilant on this point: a belt may have been replaced multiple times without a tensioner replacement, which can serve to reduce its life and the life of the components it drives.
Under moderate conditions, the ram air effect forces air through the rad, carrying away heat. When the coolant or engine bay temperature rises above a preset point, the Cooling Fan will be activated in order to provide the air circulation required.
A Thermostatic Fan Clutch may be employed for this. In this case, the clutch is designed to lock up when the engine heat and load demand require it. In such systems, the fan clutch is linked via a belt to the engine’s rotation, via a pulley or system of pulleys.
More commonly seen now is a Fan Motor. This is activated by the Coolant Temperature Sensor, which is usually a simple bi-metallic switch that completes the circuit, activating the fan. On these systems it is important to use caution when working in the engine bay, as coolant temperature can rise even after the engine is shut off, causing the fan to activate. This sensor should not be confused with the Engine Coolant Temperature (ECT) sensor, which is linked to the engine management and fuel system but does not control the fan activation.
The Thermostat controls coolant flow to the radiator. It is designed to restrict coolant flow from the engine to the radiator until a preset temperature has been reached. Restricting coolant flow allows the engine to heat up more quickly, arriving at its proper operating temperature for good emissions and driveability.
The Water Pump is the heart of the system. Driven by a belt, it rotates and provides coolant flow whenever the engine is running.
The Coolant Tank (or Reservoir) holds coolant to ensure that there is enough for the system to operate, even if there is some loss. It is important for the pressure in the cooling system to be retained.
Maintaining pressure at safe levels may be through a Radiator Cap, or through the Coolant Tank Cap if the tank is part of the pressurized system.
The Heater Core is the key component of the passenger compartment heating system. Coolant is circulated through it and it releases heat to the air in the same way as the radiator does.
The circulation of coolant through the heater core is controlled from the passenger compartment by either levers or switches hooked up to the Heater Valve, which may be mechanical or vacuum-operated, opening and closing under the command of preset temperature settings. There are also electromechanical versions, which may be referred to as actuators.
In Automatic Temperature Control Systems, the passenger compartment temperature can be preset with the heater valve, air conditioning, blower motor, and blend doors located in the plenum, the overall name for the contained passages where air is directed to the passenger compartment, and which are controlled automatically.
Blend doors determine whether the passenger compartment receives heating or air conditioning by directing air flow either through the heater core or around it. The evaporator is generally located in such a way that it always receives air flow. Blend doors are controlled directly by levers or by actuators (electric or vacuum-operated) in automatic temperature control systems. The Blower Motor provides the forced air through the heater core and on to the passenger compartment. It may be activated by a switch in the cabin or by the temperature control system.
Although the function of the temperature control system is straightforward, when problems arise a proper diagnostic approach is still necessary. For example, if the fan does not blow warm air it could be due to low coolant (none is reaching the heater core), a stuck blend door, or on ATC systems, a faulty relay or switch. Patience is important when handling queries from consumers or technicians.