An air conditioning system that cools insufficiently or not at all is a common problem, usually caused by refrigerant leaks or a faulty compressor. This is annoying on hot days. It also indicates wear of important components in the air conditioning system. With various models, including the Seat Altea, this problem occurs regularly, especially in cars produced from 2004 onwards. Read on to discover how to recognise these problems and what you can do about them.
Why is the air conditioning no longer blowing cold air?
If your air conditioning blows lukewarm air instead of cooling, several causes are possible. The most common is a lack of refrigerant. This slowly leaks away through ageing hoses or damaged components. A clogged cabin filter is also a frequent cause. After a few months of use, the filter becomes clogged with dust and pollen. The airflow is blocked and the system has to work harder.
Another cause is freezing of the evaporator coils. Dirty filters or a low refrigerant level cause the coils to become too cold. The coils then freeze up. A faulty thermostat or a broken compressor reduces the cooling capacity. Sometimes the compressor does not engage at all. Electrical problems or corrosion at the connections are the cause of this.
‘ The most noticeable sign is that the air conditioning cools less and less well, or stops cooling altogether. ’
How to recognise a refrigerant leak
A refrigerant leak is difficult to detect with the naked eye. However, there are several signs. The most noticeable sign is that the air conditioning cools less and less well or stops cooling altogether. The system needs a certain amount of refrigerant. When the level is low, the cooling capacity gradually decreases.
Oil stains under the car sometimes point to a refrigerant leak. Refrigerant is often mixed with oil from the system. These stains usually appear at the condenser. The condenser removes heat from the refrigerant. This component is located in front of the radiator and is vulnerable to stone chips and corrosion. Ice formation on the air conditioning line or around the evaporator is also a warning sign. Are you unsure? Then have a specialist carry out a pressure test. This test makes leaks in the system immediately visible.
Can you top up refrigerant yourself?
Topping up refrigerant yourself is possible with a refill kit. However, it is not always wise to do this yourself. A car’s air conditioning system operates under high pressure. The system requires precise quantities of refrigerant. Too little refrigerant means insufficient cooling. Too much refrigerant damages the system and causes the compressor to fail.
Topping up does not solve the underlying problem if there is a leak. The refrigerant will leak away again. The problem will then remain. First, the cause must be traced and repaired. Only then is the system refilled. A specialist has the right equipment. This equipment evacuates the system. It tests for leaks. It then fills the correct amount of refrigerant according to the manufacturer’s specifications.
What are common causes of air conditioning failures?
Besides refrigerant leaks and a dirty filter, there are several components that can cause faults. The compressor is the heart of the air conditioning system and pumps the refrigerant around. The compressor wears out over time. Insufficient oil in the refrigerant accelerates this wear. Frequent switching on and off also speeds up the wear. Rattling noises or a compressor that does not engage are typical signs of failure.
The condenser removes heat from the refrigerant. This component is sensitive to damage from stone chips and corrosion. In high-mileage cars, problems regularly occur here. The evaporator can also leak or become clogged with dirt and pollen. The evaporator (the component located under the dashboard that evaporates the refrigerant to cool the air) is vulnerable to moisture and dirt. If you do not regularly replace the cabin filter, this problem gets worse.
The fan or blower can fail. This component provides the airflow from the air conditioning system into the car. A weak airflow or squeaking noises point to a problem with the blower. The blower is often located behind the dashboard and is difficult to access.
‘ Preventive maintenance prevents more extensive repairs. ’
What does AC repair or servicing cost?
The cost of air conditioning repairs varies widely. Different components require different budgets. Labour time also differs per repair. Replacing a cabin filter is, at around 20 euros, one of the cheapest maintenance jobs. Topping up the refrigerant at a garage usually costs between 50 and 100 euros. The garage will also check for leaks.
Repairs to the compressor or condenser are more expensive. Replacing a condenser costs on average between 200 and 400 euros. A new compressor quickly costs between 300 and 800 euros. The make and model determine the price. Labour costs are added on top. Some components are difficult to access. For example, an evaporator under the dashboard requires a lot of labour time. Preventive maintenance, such as an annual air conditioning check, costs between 40 and 80 euros. Preventive maintenance prevents more extensive repairs.
Practical tips to prevent air conditioning failures
Regular maintenance extends the lifespan of your air conditioning system. Replace the cabin filter at least once a year. Do you often drive through dusty or pollen-rich environments? Then replace the filter more often. Use the air conditioning regularly in winter. This keeps the compressor and hoses supple. Seals do not dry out and do not start to leak.
Keep the condenser clean. Check the condenser for damage. The condenser is located at the front of the car and collects a lot of dirt, leaves and insects. Rinse the condenser regularly with water. This helps the condenser function properly. Pay attention to where you park. Trees and plants bring dirt into the system.
Do not overuse the air conditioning at outside temperatures below 5 degrees Celsius. Excessive use at low temperatures leads to freezing of the evaporator coils. Has the cooling performance decreased? Then do not wait too long. Taking action early prevents more serious damage and higher repair costs. Consult a specialist if you are in doubt or hear unusual noises.
Signs that your air conditioning system needs attention
Your air conditioning system gives various signs. These signs show that maintenance or repair is needed. The cooling capacity decreases. Does the air conditioning only blow lukewarm air? Does it take longer for the air conditioning to cool the car down? This indicates a low refrigerant level. It also suggests a poorly functioning compressor.
Unusual noises such as rattling, clicking or squeaking are a warning. These noises occur when the air conditioning is switched on. Problems with the compressor, the blower or a loose belt cause these sounds. An unpleasant smell comes from the vents. This is a sign. Mould or bacteria in the system cause the smell. Moisture in the evaporator is often the cause.
A blocked drain from the evaporator causes water leakage in the car. Normally, condensation is drained outside via a hose. Water enters the car when the hose becomes blocked. Pay attention to the temperature difference between the inlet and outlet of the air conditioning. The temperature difference should be at least 10 degrees Celsius in a properly functioning system.
‘ Regular maintenance prevents costly repairs. ’
Discover more about car maintenance
A properly functioning air conditioning system contributes to driving comfort and safety. This applies during warm periods. Regular maintenance prevents costly repairs. Acting in good time when problems arise keeps the system in optimal condition. On the Carnews website you can find more information about common car problems and maintenance tips. You will also find practical solutions for different car makes and models. There you can read everything about maintaining your car.
Frequently asked questions
A poorly functioning air conditioning system can put extra load on the engine, especially if the compressor is running heavily or starting to seize, which can slightly reduce your engine performance (slower acceleration). Because the engine has to work harder to drive the faulty or inefficiently running air conditioning pump, fuel consumption usually increases. In extreme cases, with an almost seized compressor, power can noticeably decrease and the engine may even start to run less smoothly. Switching off or repairing the air conditioning can then improve both performance and fuel consumption.
You can check whether the air conditioning settings are correct (AC button on, low temperature, fan speed and air distribution set correctly) and listen to see if you clearly hear the compressor engaging (clicking sound under the bonnet). Check the interior filter for contamination or blockage and replace it if necessary. Visually check whether the condenser at the front (in front of the radiator) is not completely clogged with dirt, leaves or insects and carefully clean it. Finally, check the relevant fuses for the air conditioning/fan in the fuse box to see if any have blown.
The most common causes of a non-functioning air conditioning system are a clogged interior filter, too little refrigerant (leak), a faulty compressor and problems with the interior fan. In broad terms, you distinguish them as follows: with a clogged filter, the airflow is weak but you can still hear the fan; with a refrigerant leak, the airflow is normal but the air remains lukewarm. With a faulty compressor you do not hear a clear “click” or the compressor does not run and the air conditioning does not cool, despite the correct settings. With a faulty fan, you hear no blowing or an irregular blowing sound and hardly any air comes from the vents, even though the air conditioning is switched on.
Simply ‘topping up’ refrigerant is almost always a temporary quick fix. In a closed air conditioning system the refrigerant should not run out, so if the pressure is too low there is usually a leak or another fault. Without tracking down and repairing the leak, the refrigerant will escape again and the problem will return. A sustainable, ‘permanent’ solution is therefore: detect the leak, repair it and then refill according to specification.
Regularly replace or clean the interior filter and keep the condenser free of dirt, leaves and other blockages. Have the air conditioning system checked at least once a year for refrigerant level, leaks and the condition of the compressor and pipework. Use the air conditioning now and again in winter to keep the seals supple and limit internal corrosion. Avoid DIY refrigerant refills and always have this done by a specialist to prevent wear and damage.