Car Air Con Servicing: Why It Is Worth Doing Before Summer

How car air conditioning works, briefly

The system is a sealed circuit. A compressor driven by the engine pressurises refrigerant, which flows through a condenser at the front of the car, where it gives off heat, then through an expansion device and an evaporator behind the dashboard, where it absorbs heat from the cabin air. A dryer removes moisture and the whole thing is held together by pipes, seals and sensors.

Because it is sealed, refrigerant does not get used up like fuel. If the level is low, there is a leak somewhere, even if it is a small one. That is why a service is about more than adding gas.

What an air-con service looks at

The details vary, but a sensible service covers the main parts of the system and how they are performing, and it records what was found so you know the state of the car.

• Visual inspection of pipes, joints, condenser and compressor for damage or oil traces
• Checking the system pressures and the temperature coming from the vents
• Leak checking, which may use a UV dye or electronic detector
• Checking the compressor clutch engages and the cooling fans run
• Condition of the cabin filter
• Recovering the old refrigerant and refilling to the correct specification where appropriate

Leak checks and why they matter

Refrigerant carries a little oil that lubricates the compressor. When refrigerant escapes, oil goes with it, and a compressor running low on both can be damaged. Finding a leak early means a smaller repair, such as a seal or pipe, and not a compressor replacement later.

Leaks tend to appear at joints, hoses, the condenser, which sits at the front and takes stone chips and road debris, and the compressor shaft seal. Tyneside coastal air and winter road salt can speed up corrosion on exposed parts. If a leak is found we will explain where it is and what repair is usually involved. It is also why regular use helps, as we discuss in our article on running air con in winter.

The cabin filter and air quality

The cabin filter cleans the air coming into the car through the vents. When it clogs with dust, pollen and leaves, airflow drops and the system seems weaker than it is. A damp, dirty filter or evaporator can also be a source of musty smells. Checking the filter at the start of summer is cheap insurance against both problems, and an obvious first step if the air feels weak.

A smell that persists after the filter is dealt with can point to the evaporator itself, which is a separate diagnosis.

Performance, noise and the heating link

Cold air that takes a long time to appear, a compressor that clicks on and off rapidly, rattling or squealing from the front of the engine and vents that blow warm all suggest something needs attention. Once cooling is checked, we can look at what is causing it, rather than just guessing.

Air con and heating share parts. Both use the same blower fan, vents, flaps and often the same control panel and cabin filter. Air con also dehumidifies air, which is why it helps clear misted windscreens. A blend flap actuator that is stuck may affect hot and cold temperatures. If you have a heating problem as well, say so, because we also repair heating systems and can check both at once.

When to book it in

Spring, before the first warm spell, is a sensible time. Book earlier if the system has been weak or noisy, if you have noticed damp smells, or if you are planning a long summer journey. At Banks of the Tyne in Hebburn we carry out air-con servicing, re-gassing, diagnostics and repairs. How long the service takes and what any repair would involve depends on your car, so ask us when you get in touch.

Frequently asked questions