Cooling System Service & Repairs

In Australia, car engine cooling system failures rank among the top three causes of roadside breakdowns, with radiator failures accounting for a large percentage of these.  A fully functional and efficient cooling system circulates coolant to reduce heat around your engine and is essential in preventing overheating.

Not all cooling system failures are explosive in nature; in most cases, it's a slow process that may start with you noticing puddles under the car or having to top off the coolant level regularly. The temperature gauge may indicate a high coolant temperature in slow traffic but returns to normal during high speed driving. In some cases, you may notice a sweetish, “hot water” smell coming from the engine, or even notice actual steam coming from under the bonnet.  All these symptoms are serious and should not be ignored.

Your local Repco Authorised Service centre can carry out a wide range of services including:

• Radiator replacement
• Radiator repair
• Radiator flush
• Radiator cap replacement
• Coolant replacement
• Cooling system check
• Thermostat replacement
• Water pump replacement
• Radiator Hose Replacement

In simple terms, a vehicles’ cooling system consists of components that manage and maintain the engine’s temperature, regardless of factors such as ambient temperature and operating conditions like road speed.
Major deviations on either side of an engines ideal operating temperature can cause serious engine damage.    
In modern vehicles many manufacturers have adopted engine technologies that rely heavily on the engine temperature to reduce emissions, so it is now possible to find engines in late-model vehicles that run 20 or more degrees hotter that what is considered normal in older engines.Regardless of what you drive, it is critical that your cooling system is in premium condition to help protect your car from expensive breakdowns.

Your car’s cooling system consists of more than just a radiator and coolant.  Learn more about the common components of your cooling system below.

Radiator
Also known as a heat exchanger, the radiator is made up of two reservoirs on either side of a core of small-diameter tubes that are all interconnected with a fine web of aluminium foil that greatly increases the surface area of the radiator that is in contact with the atmosphere. As the hot coolant flows through the small tubes the heat stored in the coolant is shed, or “radiated” away to the atmosphere, hence the name, radiator.

Radiator cap
On modern cooling systems, the radiator cap is located on the expansion tank, a device that allows for expansion and contraction of the coolant. Although modern radiator caps are mostly made of plastic, they are designed to contain a pressure relief mechanism whose purpose it is to both contain the pressure caused by expansion of the coolant, and to relieve excess pressure in order to maintain the cooling systems’ design pressure.

Radiator hoses
The radiator hoses transport coolant to the radiator, and from the radiator back to the engine. Therefore, it is critically important that the hoses be in perfect condition.

Water pump
The water pump can be thought of as the heart of the cooling system, in the sense that the pump circulates coolant throughout the entire cooling system. Until comparatively recently, all water pumps were driven by the engine via a drive belt, but electrically operated water pumps are becoming more common. 

Coolant
If the water pump is the heart of the cooling system, the engine coolant can be thought of as the lifeblood of the system. Consisting of a mixture of clean water and a specialised additive that prevents the coolant from either freezing or boiling, the coolant absorbs heat from the engine as it circulates through the engine. This heat is shed to the atmosphere when the hot coolant passes through the radiator, which is the principal mechanism that controls the engines’ temperature.
It should be noted that all antifreeze/antiboiling additives have finite service lives, since the active ingredients become degraded over time. Therefore, the entire coolant mixture must be replaced at least once every two years, or according the vehicle’s prescribed maintenance schedule in order to extract the maximum benefit from these additives.

Thermostat
The function of the thermostat is to regulate the circulation of the engine coolant, using the coolant’s temperature as a trigger to either open, or close. Depending if it’s open or closed, the thermostat controls the time the coolant spends in the radiator. For instance, if it is stuck open the coolant will circulate too fast, which can cause the engine to overheat.
If the thermostat is stuck closed, the coolant cannot circulate at all, which can cause an engine to overheat fatally in a matter of seconds.

Antifreeze/antiboiling additive
The primary functions of this additive are to raise the boiling point of the coolant to beyond the boiling point of pure water at sea level, and to lower the freezing point of pure water to below the freezing point of pure water at sea level, while inhibiting internal rust and corrosion at the same time.
Each vehicle manufacturer requires that a specific formulation of additive be used in a specified concentration relative to clean water, since different additive formulations/concentrations yield different results in different applications.    

Radiator fan
The purpose of the radiator fan is to draw air through the radiator core to increase the rate at which heat is exchanged between the coolant and the atmosphere.

Fan switch/sensor
Electric radiator fans are activated by the coolant temperature as measured by a dedicated switch/sensor. In some cases, this switch has two circuits, each of which activates a circuit that causes the fan to run at a preset speed. Both circuits must be fully functional for the cooling system to function optimally.

Engine coolant sensor
The efficiency of many critical engine management functions is predicated on the assumption that the engine coolant is correct, as measured by one or more engine coolant temperature sensors. If one or more of these sensors are defective, they supply the ECU (Engine Control Unit) with incorrect, implausible, erratic, or no input data at all, which can cause engine overheating and poor fuel economy as secondary effects of the coolant temperature sensors not working properly.

Coolant level sensor
Some vehicles are equipped with a dedicated sensor on the expansion tank whose function it is to monitor the level of the coolant in the system. While a failure of this sensor will not cause the engine to overheat, or effect the overall operation of the cooling system, warning signals from this sensor should NEVER be ignored, since it may be that the warning signal is alerting the driver that a serious and potentially catastrophic coolant loss has occurred.

Modular Coolant Hose
Instead of a single hose, the modular coolant hose assembly consists of a number of connectors and hose modules. These modules can be a branching tee in the hose, quick-connect, valve, drain, air-bleeder or sensors.