Car Air Conditioner Making Hissing Sound? Here Are the Causes & How to Overcome It

The hissing sound from the car's air conditioning can occur suddenly. This issue often confuses many car owners. This condition certainly makes the car's AC unable to cool the temperature inside the car at all. 

So why can this happen? To answer that question, let's take a look at the following review.

Causes and Solutions for Hissing Car AC

There are several things that can cause a car's AC to hiss that need to be known. Here are the complete causes along with how to address them.

1. Improper installation of AC components

The cause of the hissing sound from the car's AC is usually due to the improper installation of car AC components. This usually happens because the car owner installs the AC independently without having the expertise. To resolve this issue, it is necessary to seek help from a qualified AC technician.

2. Issues with the magnetic clutch

The next cause may be due to a problematic magnetic clutch. This issue usually occurs due to poor quality magnetic clutches or counterfeit ones, as well as the age of use. As is known, the magnetic clutch is a component that connects the engine to the AC compressor. If this component is damaged, it can be ensured that the AC cannot cool the cabin temperature and will hiss.

3. Low or depleted freon

A decrease in freon capacity or depletion is also one of the causes of the hissing sound from the car's AC. As is known, AC freon can be considered the main energy source for the AC to cool the temperature inside the car. Continuous use of the AC will certainly reduce the freon capacity or even deplete it. 

If the freon is depleted, other AC components will work harder, causing a hissing sound. Additionally, this condition can accelerate the wear and tear of other AC components. To address this, you need to regularly check the freon capacity so that you can refill the freon before it runs out.

4. Dirty evaporator

The next cause may be due to the condition of the evaporator, which is rarely cleaned, resulting in a buildup of dirt and dust. This condition can reduce the AC's performance, making it feel less cold and causing other components like the thermostat and compressor to work harder. 

This condition can cause the flow rate of freon to increase rapidly. This is what causes the AC to emit a sound like hissing. To address this, you need to regularly check this component. If it is dirty, you need to clean it immediately.

5. Clogged expansion valve

The next cause may be due to a clogged expansion valve. As is known, this component has a small hole that serves as an outlet for freon (in liquid form). 

When the freon passes through the hole in the expansion valve, a hissing sound usually occurs. When the expansion valve is dirty, the freon discharge process will be blocked, accelerating the flow rate of the freon. The faster the flow of freon, the stronger the hissing sound, which can even be heard at the AC vents. 

To address this, you need to regularly check this component. If it is dirty, you can clean it.

6. Problematic tensioner pulley

A problematic tensioner pulley can also cause the car's AC to emit a hissing sound. The tensioner pulley component itself can easily get damaged if you often use the AC in full cold mode. Why is that? Because when you use that mode, it makes the pulley work harder. To resolve this, you need to replace this component with a new one. 

Thus, some causes and solutions for a hissing car AC. If you feel less skilled in addressing it, you should use the services of a professional AC technician or visit the nearest Daihatsu workshop for proper handling.