Part 5: Cooling Systems

In previous articles, we have explored the different components that make up the vehicle cooling system. In this week’s edition, we wrap up our series on cooling system, with the last two components to be covered – the heater core and the various hoses. 
2.10 Heater Core 

The hot coolant is also used to provide heat to the interior of the vehicle when needed. This is a simple and straight forward system that includes a heater core (which looks like a small version of a radiator) that is connected to the cooling system with a pair of rubber hoses. One hose brings hot coolant from the water pump to the heater core and the other hose returns the coolant to the top of the engine. 

 

There is usually a heater control valve in one of the hoses to block the flow of coolant into the heater core when maximum air conditioning is called for. 

 

A fan, called a blower, draws air through the heater core and directs it through the heater ducts to the interior of the car. Temperature of the heat is regulated by a blend door that mixes cool outside air, or sometimes air-conditioned air with the heated air coming through the heater core. This blend door allows you to control the temperature of the air coming into the interior. 

 

Other doors allow you to direct the warm air through the ducts on the floor, the defroster ducts at the base of the windshield, and the air conditioning ducts located in the instrument panel. 

 

2.11 Hoses 

 

There are several rubber hoses that make up the plumbing to connect the components of the cooling system. The main hoses are called the upper and lower radiator hoses. These two hoses are approximately 50mm in diameter and direct coolant between the engine and the radiator.

 

Two additional hoses, called heater hoses, supply hot coolant from the engine to the heater core. These hoses are approximately 25mm in diameter.

 

One of these hoses may have a heater control valve mounted in-line to block the hot coolant from entering the heater core when the air conditioner is set to max-cool.

 

A fifth hose, called the bypass hose, is used to circulate the coolant through the engine, bypassing the radiator, when the thermostat is closed. Some engines do not use a rubber hose. Instead, they might use a metal tube or have a built-in passage in the front housing.

 

These hoses are designed to withstand the pressure inside the cooling system. Because of this, they are subject to wear and tear and eventually may require replacing as part of routine maintenance. If the rubber is beginning to look dry and cracked, or becomes soft and spongy, or you notice some ballooning at the ends, it is time to replace them.

The main radiator hoses are usually moulded to a shape that is designed to route the hose around obstacles without kinking. When purchasing replacements, make sure that they are designed to fit the vehicle.

 

There is a small rubber hose that runs from the radiator neck to the reserve bottle. This allows coolant that is released by the pressure cap to be sent to the reserve tank. This rubber hose is about a quarter inch in diameter and is normally not part of the pressurized system. Once the engine is cool, the coolant is drawn back to the radiator by the same hose.

 

Start My Car has an extensive range of D.O.E hoses. Be sure to have a look for all your hose needs

 

Summary

Your car produces a great deal of heat when it is running, and must be cooled down continuously to avoid overheating and engine damage. To understand your car’s cooling system, it is important to understand all of the basic cooling system components. The main components of the cooling system and their functions are summarised below:

 

Coolant

An equal combination of distilled water and coolant provides both the cooling properties of water and the corrosion resistance and lubrication of the coolant

Thermostat

The thermostat regulates the flow of coolant through the cooling system by opening and closing depending on the temperature of the coolant.

Water Pump

The water pump is responsible for moving the coolant through the system. It is typically driven by the engine drive belt, timing-belt, or timing chain.

Radiator

The radiator is designed to dissipate the heat from the cooling system. When the coolant is inside the radiator, its’ heat is transferred to the surrounding air through the metal fins of the radiator.

Radiator Cooling Fans

The Radiator cooling fan is designed to push or pull air through the radiator cooling fins. This assists in the dissipation of heat when the vehicle is not moving fast enough to provide sufficient air-flow over the radiator.

Cooling System Pressure Cap

The cooling system pressure cap is typically located on the radiator or on the coolant reservoir tank. The cap holds pressure on the cooling system, allowing the coolant and water mixture to reach a higher boiling point which makes it more efficient.

Hoses

Hoses are designed to be flexible connections that carry coolant (antifreeze) between the engine and other temperature sensitive components on the car. Radiator hoses are the largest, most well-known. They attach the radiator to the engine. They route coolant to the radiator to be cooled and then return it back into the engine, so it can keep a certain temperature and run at peak efficiency. Heater hoses direct coolant into the car’s heating unit. Other smaller hoses bring coolant into other components, like a throttle body or pump, or intake.

 

With this, we wrap up our series of the individual parts of the cooling system. In coming articles we will address the maintenance aspect of each component, how to test if it is failing, what are the tell-tale signs and symptoms of a component going west. 

 

Til’ next week. Keep well and Keep Safe, and if you’re an engine, Keep Cool.