How To Clean a Car AC Evaporator Without Removing It

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Are you experiencing inadequate or low cooling in your car? It may be the cause of the failure of the AC evaporator. To enjoy seamless air conditioning in your car, clean the AC evaporator occasionally. Here is an article on how to clean a car AC evaporator without removing it.

How To Clean A Car AC Evaporator Without Removing It

Ac evaporator gets dirty over time. It gets mold, fungus, or gets contaminated with other components. We recommend you clean the car’s AC occasionally to keep it running efficiently. 

Materials Required

  • Electric drill
  • Screwdriver
  • Water hose
  • RTV silicon cleaner
  • ⅜ inch drill bit
  • AC evaporator cleaning solution
Front seating of a car

Step 1: Locate The Car’s AC System

To clean the air conditioning of the car, you must find the evaporator first. The AC is located near the firewall separating the passenger area from the engine compartment. 

The evaporator of the AC is situated behind the dashboard, from where it supplies cool air all around the car.

Step 2: Check The Evaporator

Before indulging in deep cleaning the car’s AC evaporator, make sure there is some definite problem with the evaporator.

  1. Attach A/C gauge set into the service ports of the car. Make sure you read the manual instruction properly before attaching the gauge set. 
  2. Add a can of refrigerant to the system that contains leak detection dye. Put the leak detection dye when the engine is on and set the vehicle to ‘AC Max.’ 
  3. You will find the low-pressure valve; mostly, it is marked. If it isn’t marked, then check the nozzle of the refrigerant that fits in the nozzle. The refrigerant can is made for a low-pressure valve, and it cannot fit into any other valve.
  4. Once you fix the refrigerant, keep rotating it in a 3 to 6 clockwise direction. It will spill the UV liquid into the valve.
  5. When the can gets empty, retrace the path of the leak detection dye. It has a UV color so, you can check with UV light in the garage.
  6. Check if the dye drips out of the condensation tube. If there is a leak in the condensation tube, it proves the evaporator is leaking.

Turn off the engine, and the dye will pass to the passenger compartment through AC vents in the dashboard. Follow the article to learn about leak detection with leak dye. 

Step 3: Check Evaporator Core

  1. Remove the blower fan, use ⅜ inch drill set to remove the blower fan. Be careful; remember you have sealed the hole later.
  2. Once you have access to the unit of evaporator core, you can spray the cleaner onto this unit.
  3. Let the cleaner sit for an hour or two so it disinfects the AC evaporator properly.
  4. The cleaner is foam-based; it turns into a liquid when applied, clears all the drain blockage.

Here is a video guide that you can follow for cleaning and checking the evaporator core.

Step 4: Rinse The Area With Water

After cleaning the AC evaporator with cleaner, rinse off the liquid with water.

Car engine
  1. Take a garden hose with low pressure to rinse the liquid from the car.
  2. Take some assistance, a person who keeps an eye on the car, that you are not filling the car with water.
  3. Alternatively, you can use a spray bottle to clean the liquid from the car. But, again, it is for those uncomfortable with water hoses and finds them difficult to handle.

Use a dry towel to dry off the AC evaporator. You can use a blow dryer or hairdryer to do this job. Do not proceed to the next step until it is completely dry.

Step 5: Seal The Heater Box

After cleaning the AC evaporator in the car without removing it, retrace your steps back and fix everything that you have opened while cleaning the evaporator.

  1. Fix the blower fan the way it was when you opened it.
  2. If you have opted for drilling, use RTV silicone from the tube to seal the opening completely. 

With these following steps, you can clean the evaporator of your car. This process does not take much time and helps to maintain the AC evaporator.

Maintenance Of Car Evaporator

Like most AC, a car’s Ac and its component are prone to collect dust and debris. The dust gets accumulated in the AC vents can clog the system. The clogged system leads to uneven cooling, leaks, and low performance of AC. 

To improve the performance and efficiency of the AC, you must clean it often. Therefore, the AC system should be checked and cleaned regularly.

Have the condenser cleaned, the condenser converts the high-pressure gas to a low-pressure liquid, and then it steams and moves to the receiver dryer. Removal of debris and dirt from the condenser allows optimal airflow.

To keep the system in good health, consult a technician or car service center to evaluate the condenser for any loose wires or clogged up paths with dirt and debris.

Examine the filters; the air conditioning filters are installed behind the glove box in a car. The filter cleans the air as it moves through the HVAC system. Unfortunately, filters collect harmful pollutants from the vehicle, sometimes it gets clogged up, which reduces the system’s efficiency. 

A filter should be cleaned once in a while; a dirty filter carries the dirt to the evaporator, impairing the air conditioner’s internal system.

Signs To Know The Evaporator Is Falling Apart

Like most ACs, a car’s AC gives signs that show you must clean the evaporator. The evaporator is a major part of the car. Hence it is easy to find when something is not right. Here are some signs which make it easier to detect any issue in the evaporator.

Clean car ac evaporator
  • Car Is Not Cooling Properly: This is one of the easiest ways to determine that the evaporator is not working well. It can be due to clogged up drains or leakage in the system.
  • Strange Odor From The AC: If the evaporator is leaking, some amount may get into the coolant; hence you can get a sweet smell inside the car. If the smell increases over time, you must take the car to a mechanic to check for any leakage. 
  • AC Temperature Varies: If the temperature is inconsistent and the cooling fans are not working well, it can signify a damaged evaporator.

These are warning signs, which you must take seriously. Damage to the AC evaporator can cause severe damage to the car. It is advisable to reach out to a mechanic for a proper check-up and repair if required.

Frequently Asked Questions

How Often Should Evaporators Be Cleaned?

It must be cleaned once a year. But, you should also consider the area you live in and the pollution level of that area. If you have an old car, then regular maintenance of the coils, radiators, and other parts can keep up the health of your car.

Can I Use Vinegar To Clean The Evaporator Coils?

No, it is not advisable to clean the evaporator coils with white vinegar. It is a known disinfectant and an effective cleaning agent that cleans debris and dust, although it is harmful to humans in vapor.

Most importantly, vinegar has a particular smell, which isn’t pleasant. Using white vinegar can lead to a foul smell in your car.

How Long Do Evaporator Coil Lasts?

Evaporator coil lasts 10-15 years. Suppose it is kept in good maintenance and care. With regular maintenance, the longevity of the coil enhances; it can last more than 15 years if proper cleaning is done occasionally.


The AC evaporator is the heart of your car’s AC system. Cleaning it ensures smooth airflow in all the vents. For this reason, you have to keep good maintenance and keep it clean.

We hope this article aids you in getting your AC evaporator cleaned without much hassle. However, it could be cleaned in a better way if the components were disentangled from the system.