Automotive Heaters and Cooling Systems Use caution when working around radiator & heater, hoses and coolant. They can be very hot. Never open the radiator cap when the engine is hot, antifreeze / water can spray out. Use of safety goggles is suggested. The hot coolant is also used to provide heat to the interior of the vehicle when needed. Heater cores can become plugged, and may require flushing or replacement. Two hoses go from the the engine to the heater core, and can develop pin-hole leaks that only show up under pressure, as when the engine is hot. Flush kits are available from auto parts stores to use a garden hose to flush the heater core and radiator. The most common problem is low engine coolant level and/or low engine temperature. Temperature from the heater outlets should be 130 degrees or more with the fan on high after the car has warmed up. In cars five years old or newer is the most common problem is a faulty engine thermostat. The older the vehicle, the more likely problems are the heater core and / or multiple other problems. If you have questions regarding Heater and Cooling System Repair, simply submit a question using the link at the top of the page.

The cooling system is made up of the passages inside the engine block and heads, a water pump 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, a heater core to transfer the heat to the passenger compartment, and some plumbing consisting of interconnecting hoses to transfer the coolant from the engine to radiator and also to the car's heater system where hot coolant is used to warm up the vehicle's interior on a cold day.

A cooling system works by sending a liquid coolant through passages in the engine block and heads. As the coolant flows through these passages, it picks up heat from the engine. The heated fluid then makes its way through a rubber hose to the radiator in the front of the car. As it flows through the thin tubes in the radiator, the hot liquid is cooled by the air stream entering the engine compartment from the grill in front of the car. Once the fluid is cooled, it returns to the engine to absorb more heat. The water pump has the job of keeping the fluid moving through this system of plumbing and hidden passages.