Does Running the AC Use Coolant? (Answered)

Auto companies are always striving to make you feel as comfortable as home in your car. You should spend as much to make the car comfortable as you would do to increase comfort in your home or office.

That’s why most cars have air conditioning (AC) to ensure a comfortable environment. You should take care of your car’s AC just as you would take care of your home’s AC.

Most of the time, car users question whether the car needs coolant to run the AC or whether the coolant affects the AC. In addition to these, they also express some other doubts about the AC of their car which we have highlighted in this article.

Does Coolant Have Any Effect on Car AC?

The modern vehicles we see on the road today are not affected by the AC coolant, but by the AC condenser that can be seen in front of the radiator. There are two main reasons why your car’s AC performance may be affected:

The first is the AC cutoff. When the engine needs extreme cooling, it removes the AC compressor to reduce the temperature of the radiator. With use, the car gets old and its cooling system also deteriorates. The coolant affects when the efficiency of the AC decreases.

However, Another reason is that if the car has an air cooler or oil cooler and it creates an extra load in front of the condenser, then the performance of the AC decreases. 

What are the Differences between Antifreeze and Coolant?

Antifreeze is a liquid that is made based on ethylene glycol. It does not explode or freeze easily. On the other hand, when antifreeze and distilled water are mixed it turns into engine coolant. You will find it in the market as pre-mixed.

However, both antifreeze and coolant liquids are used for the same purpose. The difference is that one is the concentrated version and the other is pre-mixed. That’s all about the difference between antifreeze and coolant.

How to Know if Your Coolant Is Working Correctly?

This is a great question to ask if you know your car’s coolant is working properly. You do not have to go to a mechanic to find out. You can understand this only by touching the hose of the radiator below.

First, turn on the car engine because it must be done. Make sure the engine is operating at the right temperature. Now place your hand on the radiator. If you feel hot in your hands then you need to understand that the coolant is working properly. 

On the other hand, if you feel cold in your hands, then understand that the radiator hose is limited. Keep in mind that this condition can cause AC problems in your car.

How does Coolant Affect the Humidity of the Car?

The AC in your car performs just as much as the AC in your home manages the humidity in your home. The coolant top is left in the car to maintain the humidity inside the car. 

For this, the engine of the car has to have enough humidity. If proper humidity is maintained inside the car then you will not feel excess moisture or dryness or sweat.

How does Coolant Affect the Airflow of the Car?

If your car does not have the right amount of coolant then the airflow of the AC is disrupted. This is because the role of coolant is behind the cold air that flows through the AC vent of a car.

How does Coolant Affect the Temperature of the Car?

You may feel a relatively high temperature inside the car when the coolant is running close to the engine. This is because this fluid fills the inside of the car with warm air by blocking the extremely hot air of the car.

How to Know the Car AC Is Low on Coolant?

How do you know if your car has a lack of coolant in the AC? There are some visual cues through which this problem can be easily detected. E.g.

How to Know the Car AC Is Low on Coolant

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AC Gauge Reading

You can mount a manifold gauge on the high-to-low-service port if you want to measure the pressure of your car’s AC system. It is an easy method to do.

Connect the high-side gauge hose, which is red, to the high-side service port, and the low-side gauge hose, which is blue, to the -side service port. 

Now turn off both engine and AC and release the gauge knobs. In this case, the constant pressure on the gauge will be 80 to 105 psi. 

Leaving the car idle and setting the AC to the highest level, the low-side gauge reads 25 to 35 psi and the high-side gauge 200 to 350 psi. When these results are low or even zero, it means that there is an error in the refrigerant.

Hot Air Is Coming Out of the AC

Have you ever noticed that after installing AC in the house, it is getting hot or airy at room temperature? If yes, then probably the warm air coming out of the AC vent due to low freon.

The AC of a car works through its compressed refrigerant conduction. If the amount of fluid drops below a certain level, the performance of the AC decreases, and warm air escapes from it. Then you need to understand that the level of Freon in AC has decreased or decreased.

Failed to Engage AC Clutch

Turn on the car’s AC and keep listening to it. Heard a ‘click’ sound? If yes, then know that it was the sound of clutch engagement and it means that everything on the AC is working properly. 

The significance of this clutch engagement is that it reads Freon’s level and works by allowing the compressor to compress Freon. 

However, this clutch will fail to engage when the AC’s freon level drops too low. This indicates insufficient refrigerant to compress the compressor.

Disruption of Cooling Capacity

When the car’s AC system loses its freon, its cooling capacity decreases. If the Freon drops slightly below the correct level, you will notice a difference in the cooling power of the AC.

You will see that the AC is releasing relatively less cold air. Also, if there is a leak in the cooling system of the AC, there is a deficit in its performance.

How to Check the Level of AC Coolant in the Car?

Since we are talking about the exact level of AC coolant in almost every step of this article, we should know how to check it.

First, let the car cool enough. Then lift the hood. Now, you have to find the reservoir tank. Note that the tank is made of-grade plastic. Generally, all vehicles have AC coolant stored in the reservoir tank. 

Don’t panic if you see a difference in the color of your car coolant and someone else’s car coolant. Because it comes in different colors depending on the characteristics.


If you ask if the coolant affects the AC, the direct answer is YES. The coolant certainly affects the temperature of your car’s AC. Coolant is just as important as fuel for a car.

Whenever the coolant level in your car drops too much, the inside temperature will change according to the outside of the car. Such as burning temperature on hot days and freezing temperature on cold days.

If the car’s AC system is damaged or defective due to la ack of coolant, it can cost a lot to repair or replace it. So if you have such a problem in your car then take quick action without delay.

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William Baldwin

This Is William Baldwin, The Founder & Managing Editor of this website. Me and my team share automotive tips, tricks, and news