Signs Of Bad Evaporator – How To Tell If AC Evaporator Is Bad?

A damaged air conditioner is one of the most aggravating circumstances that any automobile owner may experience, especially in the summertime.

Modern air conditioning systems have several components that must function in unison to convert heated air to cold air.

Among these components, the AC evaporator is a critical component of the automotive air conditioner.

While this part should be able to tolerate repeated usage for several years, issues can and frequently do arise without notice.

If you need to see the signs of bad evaporator, keep scrolling down for more information!

What Does the Evaporator Coil Do?

Signs Of Bad Evaporator

The evaporator coil is a critical component of any air conditioning system. This coil is necessary for collecting heat and converting it to cooled air.

The liquid refrigerant is contained in the coil pipe, then transformed into a low-pressure gas. Heat may be separated from the warm air from the atmosphere and flows through the evaporator’s coil.

Next, the air is cooled, causing humidity to condense and lowering interior humidity via the condenser line.

Finally, refrigerant is transferred from the AC evaporator to the internal unit. Coolant will be delivered to the car and distributed via the air duct system.

As a consequence, you may relax in comfort inside the vehicle.

Signs Of Bad Evaporator

Dirt and Deposits

How to know if your ac evaporator is bad? Poor performance is the first indicator of a bad AC evaporator, as it is with most air conditioning issues.

Because the AC evaporator is the key component that takes heat from the air, determining the failure is simple.

However, there are some more symptoms of a bad ac evaporator that you might find in your vehicle:

Poor Cooling And Varied Temperatures

The evaporator’s major function is to cool the air; if you notice that the air conditioning system is not chilling the air adequately or blowing out completely hot air, this might indicate that the evaporator is faulty.

The coil may decay, corrode, or be harmed in some other manner over time.

This keeps it from collecting heat from the surrounding atmosphere, forcing your air conditioner to pump out warm air instead.

Frost Build-Up & Frozen Coils

One of the typical signs of a bad AC evaporator is frost accumulation. This is a particularly vexing issue since it causes your AC unit to cycle on and off more frequently, burning more power than normal.

The increased cycle frequency is merely due to the coil’s inability to cool the airflow owing to frost formation on its surface.

If you experience this problem with a new AC unit, you may have a coil repair shop performed by a skilled HVAC technician.

If the trouble is with an older gadget, you will almost certainly need to change the coil.


Water may be seen trickling from the coil. This is fine in tiny amounts because it is merely water condensing from the interior atmosphere.

However, excessive water leakage in the coil region indicates a more significant problem.

This might happen when the coil itself is compromised. To identify the leak in AC, you can use the compressed air.

Unusual Noises and Sounds

The interior unit normally generates odd sounds and noises when the evaporator fails.

Hissing, screeching, or pounding sounds may indicate that the coil requires to be serviced or replaced. These noises are frequently coupled with other AC issues.

As a result, an HVAC specialist will be required to analyze these sounds and establish whether the AC evaporator coils generate them. But keep in mind that the noise might stem from the heat fan as well.

Dirt and Deposits

As signals of bad ac evaporator symptoms, dirt and other debris can accumulate on the coil over time.

These layers prevent heated air from communicating immediately with the coil, lowering the AC unit’s effectiveness.

If dirt and debris are not removed promptly, they might become permanently lodged on the coil, causing corrosion and other issues.


Corrosion in the AC evaporator coils develops for a variety of causes. Notably, chemical aerosols used inside can combine with condensed air and come into interacting with evaporator coils.

These chemicals then create corrosion, resulting in minor leaks in the coil.

Oil deposits on the top of the evaporator or drain pan are a rapid indication of this. When a coil produces a highly corrosive leak, it is advisable to replace it.

Occasionally, replacing the evaporator coil with a smaller part might fix the problem. At times, the entire coil must be replaced.

AC Compressor Not Activating or Turning Off

This is one of the bad evaporator coil symptoms car. The compressor circulates the refrigerant through the AC evaporator; it operates by maintaining a specified pressure.

As a result, if there is a leakage, the pressure in the pipeline drops, and the AC stops working suddenly even when it’s hot outside. In the worst case scenario, you can’t even turn it on or off at all.

Strange Smells

A small quantity of refrigerant (not coolant) will flow out of the coil, core, or washer if your AC evaporator fails.

This will produce a lovely scent, which will be amplified if the air conditioner is switched on.

Whenever you spot a weird odor inside the car (especially stronger near the AC), it is a surefire pointer of a faulty evaporator.

A mildew-like, pungent or rubber-burning smell might blast into the car’s cabin, so pay attention to it.

Common Evaporator Coil Repairs

A variety of frequent issues plague evaporator coils. A straightforward remedy may be accomplished by changing a component in your HVAC system.

If you have one of these typical issues, you may necessitate an annual cooling system modification.

This will also involve coil cleaning to guarantee that your evaporator coil is always in good functioning order.

You should change your filters regularly to ensure that your system has sufficient ventilation to allow the evaporator coils to work correctly.

Furthermore, contact an HVAC specialist immediately if you observe a frozen or leaky evaporator coil.


Why is a Clean Evaporator Coil Important?

It is critical to keep your evaporator coils clean and well-maintained to make sure your machine is running efficiently. Dirty coils can boost the energy consumption of your air conditioner by up to 30%.

Moreover, unmaintained coils can lead to additional system issues, such as poor cooling efficiency due to decreased heat transmission, compressor overheating, and frozen coils.

How Much Does It Cost to Fix An Evaporator?

The evaporator coil on a central AC takes $600-2,000 to replace. The coil is between $180 and $1,600, plus $400 to $1,000 for expert installation.


To sum up, it is critical to detect and rectify evaporator winding issues as soon as possible. With the post of signs of bad evaporator, we hope you have gained some useful knowledge.

Thank you, and see you next time!

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