Radiator Service

When you see that little warning light on your dash that looks like a tiny radiator boiling over, it normally brings a slight feeling of fear into the best of us. What causes your radiator system to overheat and how can it be fixed? It is important to remember TAG Automotive knows the ins and outs of radiators, water pumps, belts and hoses, and how to fix them.

Your vehicle’s coolant system is made up of passages inside the engine block and heads, a water pump and drive belt to circulate the coolant, a thermostat to control the temperature of the coolant, a radiator to cool the coolant, a radiator cap to control the pressure in the system, and hoses to transfer the coolant from the engine to the radiator.

The coolant withstands extreme hot and cold temperatures and contains rust inhibitors and lubricants to keep the system running smoothly.

Coolant follows a circulation path that begins with the water pump. The water pump draws coolant from the radiator and pushes it into the engine block. If the water pump experiences a leak from the seal, a cracked housing, broken impeller or a bearing malfunction, it can compromise the entire cooling system, causing the vehicle to overheat.

As coolant flows through the system, it picks up heat from the engine before arriving at the thermostat. The thermostat measures the temperature of the coolant and opens to allow hot fluid to travel to the radiator. If the thermostat becomes ‘stuck’ and quits working, it will affect the entire cooling system.

Once released by the thermostat, hot coolant travels through a hose to be cooled by the radiator. The antifreeze passes through thin tubes in the radiator. It is cooled as air flow is passed over the outside of the tubes. Depending upon the speed of the vehicle, airflow is provided by the vehicle’s movement down the road and/or cooling fans. Radiator restrictions can compromise its ability to transfer heat. These can be either external air flow or internal coolant flow restrictions. A malfunctioning electric cooling fan or fan clutch can limit air flow across the radiator.

As coolant temperature increases, so does the pressure in the cooling system. This pressure is regulated by the radiator cap. Correct system pressure is required for proper water pump seal lubrication. Increasing the cooling system pressure raises the boiling point of the coolant.

If the pressure builds up higher than the set pressure point, a spring-loaded valve in the cap will release the pressure. If an engine has overheated, the radiator cap and thermostat should be replaced.

It is important to regularly inspect the condition of your cooling system’s belts and hoses. Soft hoses, oil soaked belts, or cracked belts and hoses can have dire effects on the entire cooling system. Proper belt tension is also important.

Mineral deposits and sediments from corroded or malfunctioning parts accumulate in the cooling system. Before performing a cooling system repair, it is recommended to flush the cooling system prior to installing any new parts.