What Is Coolant?

How Does The Cooling System Work?

An internal combustion engine produces a lot of heat.

While some of that heat is removed via the exhaust system, it is the job of the appropriately named cooling system to keep the engine running at an ideal temperature and prevent it from overheating.

The cooling system consists of a number of elements, including channels that run around the heart of the engine – the block and cylinder head where all the combustion action takes place – through which coolant flows.

Other components include a water pump to circulate the coolant, a radiator to cool down the fluid, a thermostat to control its temperature, a radiator cap to keep everything under pressure and a system of hoses that direct the coolant from the engine to the radiator and back again.

When in action, the coolant absorbs the heat from the engine, moves to the radiator where it is cooled by the air flowing through the grille at the front of the car and then, once cooled, begins its journey through the system again.

The coolant itself is, usually, a blend of water and chemicals that act to lower the freezing point and raise the boiling point of the liquid.

Coolant additives also provide anti-corrosion properties.

Coolant comes in various types– often indicated by the colour of the coolant itself - and you should use the specific type recommended by your vehicle’s manufacturer.

Common Coolant System Problems

• Radiator Hose Leak
• Water Pump Failure
• Stuck Thermostat
• Blocked Radiator
• Blown Head Gasket

It’s worth going into a little more detail on the head gasket.

While any decrease in the effectiveness of the coolant system is a problem, a leak that originates from the head gasket is cause for real concern.

The head gasket sits between the cylinder head and the block, and a damaged gasket can quickly lead to an expensive repair bill and, if the problem is left to fester, the destruction of the engine itself.

How Is A Coolant System Inspection Performed?

• Coolant level will be checked, and the technician will also check that the correct coolant is being used.
• Belts and hoses will be inspected for wear and tear, cracks and proper tension and secure connections
• Radiator will be checked for leaks and signs of corrosion and clogging.
• Radiator Cap will be visually inspected and may be pressure tested.
• Water Pump will be checked to make sure its pulley is properly aligned, and hose fittings are sealed.
• Finding a cooling system leak may also require testing beyond these checks.

This may mean pressure testing or even dye testing – in which a dye is introduced to the coolant to highlight where the leak might be.

Why Is It Important To Have Coolant Checked?

An overheating engine can cause all manner of problems, with some of them being very serious and very expensive to repair.

Any sign of overheating should be taken seriously, and you should aim to get your vehicle to a mechanic on AutoGuru as soon as possible.