Warning signs of a bad AC evaporator

Your car’s air conditioner is a lifesaver during a hot summer, keeping you cool and comfortable by removing heat from the air before it circulates through the cabin. However, when the AC evaporator starts to fail, you may notice symptoms that affect its performance, like weak airflow or unusual smells. Recognising these warning signs early can help you stay ahead of potential issues and ensure your air conditioning system works effectively when you need it most.

Read our guide on the warning signs of a bad AC evaporator and how our team at Natrad can help you solve them.

What you need to know about AC evaporators

The evaporator might just be the most important part of your car’s AC system. Well, every part is important, but the evaporator is what determines the air temperature you feel inside the cabin — which is effectively what keeps you cool all year long.

Essentially, the main role of the evaporator is to absorb heat, remove humidity from the air, and distribute this cooling effect to the inside of the car via the blower fan. Usually referred to as the coil or core, the evaporator works together with the expansion valve and blower fan to circulate cool air.

If the evaporator fails, it will need to be replaced to keep the rest of the system running optimally. This is a common problem faced by car owners, especially those with older vehicles. Thankfully, there are ways you can identify problems before they get too dire.

At Natrad, we’re here to help you keep your air conditioning system in tip-top shape. With a huge range of evaporators available, Natrad will help you find the right part for your car’s air conditioning system.

How does a car’s aircon evaporator work?

The evaporator plays a key role in your car’s air conditioning system by removing heat and humidity from the air, rather than “creating” cool air. Here’s how it works step-by-step:

• Refrigerant enters the evaporator: The refrigerant flows through the air conditioning system and passes through the expansion valve, reducing its pressure and temperature.
• Heat exchange occurs: The now-cold liquid refrigerant enters the evaporator and circulates through its tubes, where it transforms into a gas as it absorbs heat. This process cools the evaporator fins significantly.
• Air cools inside the cabin: Warm air from inside your car is drawn across the cold evaporator fins. Heat is conducted through the metal, cooling the air before it’s blown back into the cabin via the blower fan.
• Humidity is removed: Moisture in the air condenses on the cold metal surface of the evaporator, forming water droplets. These droplets collect in a drain tube and may drip under your parked car—this is perfectly normal.
• The cycle repeats: While the air conditioning is on, this process continues, ensuring you’re provided with consistently cool and dry air.

By efficiently removing heat and humidity, the evaporator ensures your air conditioner delivers the refreshing relief you need, especially on hot summer days. Understanding how it works can help you identify potential issues before they become major problems.

Why are evaporators so important?

The evaporator is the heart of your car’s air conditioning system, responsible for cooling the air that keeps your cabin comfortable on hot days. By transforming liquid refrigerant into a cold gas, the evaporator removes heat and lowers the air temperature, delivering that refreshing cool air you rely on during summer. Without it, your car’s air conditioner simply wouldn’t function.

Located behind the dashboard, the evaporator is not easy to access, making replacement a time-consuming and costly process. To avoid such issues, regular maintenance, such as periodically replacing the receiver drier desiccant to reduce the likelihood of corrosion, thus preventing potential problems.

At Natrad, our expert technicians can help ensure your evaporator and entire AC system stay in top condition, giving you peace of mind and reliable cooling when you need it most.

How to tell if your car AC evaporator is bad

Keep an eye out for these common warning signs that your car’s air conditioning evaporator might need replacing:

• Weak airflow or warm air: If the airflow from your vents feels weak, it could be caused by a blockage or a blower fan issue. Warm air instead of cold could point to a refrigerant problem, possibly caused by a leaking evaporator.
• Sweet or strange odours: Refrigerant has a distinct sweet smell that can seep into the cabin if the evaporator is leaking. This smell often becomes stronger when the air conditioning is turned on.
• Compressor doesn’t activate: A refrigerant leak caused by a faulty evaporator can lower system pressure, preventing the compressor from activating and circulating refrigerant.
• Inconsistent air temperature: If the air conditioning alternates between cool and warm without reason, it could indicate a damaged or failing evaporator.

If you notice any of these symptoms, it’s crucial to act quickly. A faulty evaporator can compromise your entire air conditioning system, leading to higher repair costs. For specialist diagnosis and reliable solutions, visit your nearest Natrad store.

Possible reasons for evaporator coil failure

Corrosion

Over time, exposure to moisture and contaminants in the air can cause the air conditioner’s evaporator coil to corrode. This corrosion can weaken the structure of the evaporator, leading to leaks and reduced cooling efficiency. Use of corrosion-resistant materials can help mitigate this issue.

Clogging

Evaporator coils can become clogged with dirt, debris, or mould buildup. This restricts the flow of air and reduces the efficiency of the cooling process. Clogging can result from inadequate air filtration in the HVAC system. Cleaning dirty evaporator coils and changing filters regularly can prevent this problem.

Degrading of a seam or weld

The seams or welds in an AC evaporator can degrade over time due to the constant expansion and contraction of the coils as the system cycles on and off. This can lead to small cracks or holes, causing refrigerant leakage and a loss of cooling capacity. Proper installation and use of quality components can help prevent seam or weld issues in your evaporative cooling system.

Wear and tear

Like any mechanical component, an AC evaporator can succumb to wear and tear over years of use. The constant cycling of the system and exposure to temperature fluctuations can cause the evaporator to weaken, leading to a leak.

Leakage

One of the most common reasons for failure in vehicle air conditioning units is refrigerant leakage. Over time, the seals, gaskets, and connections within the AC system can deteriorate, leading to leaks. When refrigerant levels drop, the AC system becomes less effective at cooling. Detecting and repairing leaks promptly can help maintain the efficiency of the AC system and prevent further damage to the evaporator.

Evaporator repairs and replacement at Natrad

If your car’s air conditioning evaporator has failed, replacement is the only solution. This repair often includes recharging the air conditioning system and may involve replacing other components to restore optimal performance.

Since the evaporator is part of a sealed refrigerant system, this is not a job you can handle yourself. Professionally qualified expertise is essential, especially as accessing the evaporator often requires removing the dashboard—a complex and delicate process.

At Natrad, our experienced technicians across Australia are equipped to handle evaporator replacements and diagnose any air conditioning issues with precision. Whether you need a full air conditioning system check or a replacement part, we’re here to ensure your car stays cool and comfortable. Contact us today for professional, hassle-free service.