Cooling Systems

Your vehicle’s cooling system is definitely one of the most important systems in your vehicle, it is also one of the most neglected systems.


We will let you know a bit about the components of your cooling system and tell you how to maintain your cooling system to increase your engines life and avoid costly repairs.


Modern engines all require glycol-based coolant to be mixed in with the water in your cooling system.

This is because coolant contains a high percentage of ethylene glycol, which provides anti freeze and anti boil protection, and around four percent additives to provide corrosion protection.

To be used correctly they should be diluted to either 50% or 33% ratio of coolant concentrate to water according to the manufacturer’s requirements.

The anti freeze and anti boil protection is permanent and lasts for the life of the coolant, however, the additives that provide the corrosion protection are depleted over time. This means coolants must be changed regularly to maintain corrosion protection.

There are three categories of glycol-based coolants: Inorganic acid technology, Organic acid technology, and Hybrid organic acid technology. Each has a different recommended change interval and is recommended for different vehicles.

Your coolant level should be checked regularly (every month should be ok for most vehicles, sooner if you have an older vehicle) to make sure there are no leaks. To check your coolant level make sure the engine is cold (otherwise the radiator will be under pressure and the coolant will spray out all over you and burn you if the cap is removed too quickly); remove the radiator cap slowly, as the system is under pressure, the coolant level should be right to the top of the radiator.

Modern cars also have an expansion tank close to the radiator that has marks on the side to indicate full and low levels. This should also be checked visually to make sure the level is between the marks. If the level is low you have a leak somewhere and it will need to be repaired and the coolant concentration topped up.


Your radiator cools the coolant running through the engine by passing air over the fins and tubes. The air absorbs the heat from the coolant and is discharged into the atmosphere. The water pump circulates the coolant through the engine, where it absorbs the heat from the engine; it then flows to the radiator where it is cooled again before circulating back through the engine.


The thermostat is a device used to stop the coolant flowing to the radiator; this makes the coolant stay in the engine and helps the engine to reach operating temperature quickly.

Once operating temperature is reached the thermostat will open and allow coolant to flow to the radiator for cooling. An engine is designed to run at a set temperature range, below this the engine will use more fuel and wear will be increased reducing the life of the engine.

Thermostats can wear over time or become stuck open or closed due to overheating or scale build up from lack of coolant.

Water Pumps

A cambelt or a drive belt usually drives the water pump. Water pumps are relatively cheap items but very important and do wear out or leak over time, that is why it is recommended they be replaced with a cam belt change. The impeller can corrode away over time if coolant is not used and replaced at manufacturers recommended intervals.


Radiator and heater hoses will also be affected by a lack of proper coolant concentrations as the resulting rust and scale build-up will damage the hoses and cause them to split or burst.

Cooling Fans

All cars have a cooling fan positioned behind the radiator; it is designed to draw air through the radiator to increase the cooling effect. The fan can be driven by the engine via a viscous coupling or electrically driven and controlled. A fan that does not go can cause overheating when the engine load is high such as when towing or during hot days.

Radiator Caps

Radiator caps are often over looked when servicing the cooling system. They are also affected by a lack of coolant, mainly because the seal (like the hoses) perishes quickly without it.

To sum up, the main ways to take care of your cooling system is to check the coolant level regularly and to change the coolant at specified intervals.


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