Coolant Systems

The purpose of the Coolant System is to prevent the overheating of your vehicle’s engine. With engine reaching high temperatures, the resulting heat needs to be dissipated. An efficient coolant system is essential to prevent the engine from overheating. Another function of the coolant system is to regulate the temperature inside the passenger compartment, insuring your comfort and that of your passengers. St. Amand Auto & Truck Repair in St. Catharines can take care of all your cooling system needs.

Main Components of the Coolant System:

  • Radiator
  • Radiator Fan
  • Radiator Hoses
  • Radiator Pressure Cap
  • Coolant
  • Water Pump
  • Heater Core
  • Temperature Knob
  • Temperature Control Valve
  • Thermostat
  • Temperature Gauge
  • Temperature Sensor
  • Reservoir or Reserve Tank

How does the Coolant System work?

The radiator is the main component of the coolant system. The coolant flows through the inner core of the radiator and transfers its heat to the metal cooling fins that surround the core.

The radiator hoses link the upper and lower parts of the radiator to the engine so that the cooling fluid can flow to and from the engine.

The water pump circulates the coolant around the coolant system and into the engine block. The water pump is usually activated by either a belt located on the crank pulley or a timing belt that turns at about the same RPM as the engine.

The thermostat maintains the coolant and the engine at a proper operating temperature. When the engine is cold, the thermostat is closed, meaning that the coolant is circulated only through the engine and heater core, bypassing the radiator. Once the engine has reached its optimum operating temperature, the thermostat slowly opens allowing the coolant to flow through the radiator to prevent the temperature to rise higher. As the engine continues to operate, the thermostat constantly controls the flow of coolant to the radiator so that the engine continues to operate at optimum temperature.

The temperature gauge, is linked to a sensor located on the engine block. This sensor registers variable levels of electrical resistance as the engine heats up and allows an accurate monitoring of the engine temperature.

An overflow bottle is used as a reservoir for the coolant as it expands and contracts within the system. When hot, the coolant expands and the overflow of liquid is directed to this reservoir. Inversely, when the radiator cools down, the coolant contracts and induces a vacuum within the radiator which then pulls in coolant from this same reservoir. As the reserve tank tends to collect residues from the cooling system, it must be cleaned when the coolant is changed.

The radiator cap closes the filling hole of the radiator through which the coolant is poured. For the entire coolant system to work properly, the radiator cap is designed to seal the coolant system to a specific pressure.

Signs of troubles related to your vehicle’s Coolant System

  • Temperature gauge indicating above normal engine temperature
  • Pool of green, orange or yellow fluid under your vehicle possibly indicating a leak in coolant system
  • No or little heat inside the vehicle


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When it comes to auto repair, you need someone you can trust. With years of experience providing auto repair to vehicles all across St. Catharines and the Niagara Region, St. Amand Auto & Truck Repair has the vehicle maintenance services you need.


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