Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Air conditioning: Refrigerant
- Compressor
- Condenser
- Engine cooling fan (FC)
- Receiver drier
- Expansion valve
- Evaporator
- Blower fan.
Explanation:
A - High pressure, warm fluid
B - Low pressure, cold fluid
C - Low pressure, cold gas
D - High pressure, warm gas
Dark arrow - Warm air
Light arrow - Cold air
By allowing the refrigerant to circulate in the closed system and changing the pressure and volume it will change temperature and boil (evaporate). At the pressure found in the system, approximately 170 - 320 kPa (1.7 - 3.2 bar), the refrigerant boils at approximately 0°C to +4°C.
A condition of the refrigerant boiling is that the heat is accessible. This heat is taken from the air around the evaporator (6) where boiling occurs. When the heat is taken up by the refrigerant the surrounding air becomes cooler. It is this cooled air that is blown into the passenger compartment by the climate control system blower fan (7). The heat taken up by the refrigerant in the evaporator (6) is transported out to the engine compartment, where it is transferred to the air by the condenser (2). The condenser is cooled by the airflow and the engine cooling fan (FC) (3).
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.