The heating, ventilation, and air conditioning (HVAC) system is designed to help keep the interior of your vehicle nice and cool on hot summer days and toasty warm in the winter. There are two parts to this system, one for heating and one for cooling. A variable speed fan is used to circulate the temperature-controlled air into the passenger compartment. The knobs and vents on your dashboard help you determine how much air is released into the cabin and where you want it directed.
The heating system uses hot coolant from the engine to warm the air discharged from the heating ducts. Hot coolant flows through the heater core and warms it up. When the air moves past the hot heater core, it is warmed before being distributed out of the vents on your dashboard.
All AC (refrigeration) systems-in your car, your office, and even your refrigerator-use the same thermodynamic principles. When gas expands, it absorbs heat. When heat is dissipated from a hot gas it condenses to its liquid state. AC refrigerant is a chemical that can change from a gas to a liquid and back again at moderate temperatures and pressures. As the refrigerant transitions between liquid and gaseous forms, heat is removed from the passenger compartment and released to the outside air, which helps to cool the cabin.
There are two different types of refrigerant used in automotive AC systems:
The AC system consists of five components:
Using the AC system places extra load on the engine. If your vehicle begins to overheat, turn off the AC. If the engine continues to overheat, turn the heater on high-its small radiator will help cool the engine. If the engine does not cool down, immediately pull over to a safe location and turn off the engine. Overheating can severely damage your engine.