Updated at: 27-07-2023 - By: Lucas

It’s not uncommon for drivers to experience a foul stench in their vehicle shortly after turning on the air conditioning. Nevertheless, why is this happening? The answer to that question is what we’ll explore in this post.

The initial few minutes of running an air conditioner in a vehicle can produce an unpleasant odor. This is common knowledge for drivers who frequently use their vehicle’s air conditioning system. There is a musty, fishy smell that can be brought on by dampness from stagnant water, or it can be a combination of the two.

One of the most frustrating things about this is that most drivers would do anything to avoid smelling it, like covering their noses or opening the windows or the door. A problem with the car’s air conditioning system should be addressed if you have it, since failing to do so might result in the breakdown and eventual failure of individual components.

Why does the car ac smell bad?

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Moisture on the AC parts and other decaying materials are the most common sources of a terrible smell from the system. It’s not difficult to pinpoint where the smell is coming from. It is common knowledge that the air conditioning evaporator is where moisture and other nasty substances accumulate.

For moisture to collect and debris to accumulate on the AC evaporator, temperature fluctuations create the optimum circumstances. Aside from incorrect use of the air conditioning, scents might be created by the AC system itself.

In operation, the evaporator cools the drawn air, which leads to the formation of condensation on its surface, which then becomes the source of all subsequent issues.

When the driver arrives at his destination, the evaporator already has a significant amount of moisture on it. In addition, the accumulated dirt and dust will hasten the process even further. The cabin’s temperature causes the condensation to warm up. There will be a foul odor because of these a dozen of them.

How to remove the bad smell from the car AC?

There should be a plethora of air conditioning system cleaning products available at auto parts stores and on specialized markets. The most popular are included in the list below.

Gas cleaning spray

A gas spray is a common method for cleaning the air conditioning in an automobile. To spray the gas.

  • Start the car, turn on air recirculation in the cabin, remember, don’t take air from outside. 
  • Next, place the gas container so that it is in the flow of intake air and start to spray the agent.
  • After completing the process, do not turn off the air conditioner, close the doors, and leave the car like this for 10-15 minutes. 

Advantages and downsides can be found in using this method. When it comes to cleaning, there is no need for a lot of work, but it might also mean that nothing will change at all.

Use a special foam for cleaning

The air conditioning system can also be cleaned using this manner. It’s an improvement over the previous version in terms of both quality and efficiency. Polyurethane foam and a hose are included in the package, which can be used to spread the foam.

  • Before using it, it is best to start the engine and let it run until it reaches the optimum working temperature. After that, you should stop de car and remove the cabin filter.
  • After that, add the foam in the place of the cabin filter because in that place are the most car AC systems.
  • The foam will begin to expand on the air conditioning parts including the main source of the bad smell, the evaporator.
  • After about 20 minutes, the foam will begin to act against the debris and moisture that are present there. Let it act for another20-25 minutes.
  • When the cleaning procedure is done, turn the AC and let it work in different modes. This will help to dry out the remaining foam and removing the smell.
  • You should repeat the above steps after a while, even faster if the smell is still felt.

Disinfectant Spray by Lysol

Evap Foam 4171 75 by Nu Calgon

How to flush an air conditioning evaporator?

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On the other hand, flushing the evaporator is regarded the most dependable method for removing moisture and debris that contributes to a poor odor from the system. However, this is the most time consuming and difficult option. Note that the evaporator itself is a component of the vehicle’s air conditioning system that is refilled with refrigerant (freon).

The evaporator is located in a certain location for each type of automobile, so it is unnecessary to describe how to get there because it is specific to each vehicle. Going to an authorized workshop and having the maintenance done there is the best option.

The evaporator must be properly cleaned. In addition, you should be aware that it is nearly impossible to completely eliminate all of the dirt, mold, and bacteria from it, but conducting the cleaning in proper conditions will be sufficient. Even after a thorough washing, the scent will return. It is important to avoid breaking the seals during removal.

How long does it take to clean the car air conditioning?

The most efficient way to eliminate the most common sources of AC unpleasant smell is to disassemble and clean each component by hand. As a result, don’t plan on finishing it in an hour. 2. 3 hours is the average time it takes to clean the air conditioning system in a car on average.

How to maintain the car air conditioning?

Our previous discussion focused on how to remove the odor from an air conditioner, but now it’s time to focus on preventing or delaying the nasty smell.

First and foremost, keep an eye on the cabin filter and replace it as often as possible. If you choose a cheap filter, you’ll speed up the growth of mold, which is why you should go with a carbon-based cabin filter instead.

Secondly, wait until the vehicle is left overnight in a garage or a parking lot to dry the air conditioning evaporator. The AC should be turned off at the same time as the engine is turned off. After shutting off the air conditioning, wait at least three to five minutes before turning off the engine. If possible, wait ten to fifteen minutes.

The evaporator will dry out if you switch off the AC but leave the fan running. A significant period of time is required for the collection of moisture and grime.

The first clue that the cabin filter and evaporator need to be cleaned is the appearance of an unpleasant stench. As a result, it is imperative that you begin routine maintenance as soon as you can.