11 Painful Reasons Why Your AC Blows Warm Air While Idling

Car AC Not Cooling

Car AC not cooling is a big issue in hot weather. Almost every air conditioner user faces this problem. It is no fun traveling in a car whose car’s AC does not blow cold air. Fixing the “car AC not cooling” issue is very important to protect yourself from discomfort and dizziness in the car.

In this powerful guide, you are going to quickly learn the eleven complete reasons for car AC blowing warm air while idling within five minutes.

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AC Blows Warm Air While Idling

Car air conditioning systems became an obligatory component of the car. Nowadays, hardly a car is manufactured without an air conditioner. The air conditioner provides comfort to the car owner and passengers.

Sometimes, the car AC gives poor cooling capacity. It happens due to many reasons, but for you, it is important to know the reasons why the car is not cooling enough. So, when you visit the workshop, you have confidence in yourself that the technician does not misguide you. Below are the eleven complete reasons for car ac not blowing cold air when idle.

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11 Reasons For Car AC Blows Warm Air While Idling

Car AC Blows Warm Air While Idling can be caused by many reasons. Below are the eleven complete reasons for a car’s AC not cooling.

  1. Refrigerant Leak
  2. Defective Compressor
  3. Clogged Condenser
  4. Faulty Condenser Cooling Fan
  5. Clogged Expansion Valve Or Orifice Tube
  6. Moisture In The AC System
  7. Clogged Evaporator
  8. Overfilled With Refrigerant
  9. Dirty Cabin Air Filter
  10. Worn Compressor Belt
  11. Overheated Engine

1. Refrigerant Leak

Inspecting The AC System
Inspecting The AC System

The biggest reason for car AC blows warm air while idling is low on refrigerant.

“According to air conditioning expert of the society of automotive engineers (SAE) Ward Atkinson says, the A/C system is not fully airtight, It is nearly airtight. Refrigerants always trying to escape from the system.

Ward Atkinson

“O” ring seals and hosepipes lose their elasticity with time, which forces refrigerant to escape from the AC system. Therefore the car AC will not blow cold air when hot outside.

Related Post: 3 Types Of Car AC Refrigerant

2. Defective Compressor

Seized Compressor
Seized Compressor

A defective compressor is a common reason for a car AC not cooling. Sometimes, an automotive compressor does not work properly due to a lack of lubricating oil, which escapes with a refrigerant leak. Without enough lubricating oil, the compressor is seized and becomes defective.

As a result, the compressor will not compress the refrigerant properly, which leads to poor car AC cooling. Lubricating oil is necessary for a compressor smooth running.

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3. Clogged Condenser

Clogged Condenser

Sometimes car AC not blowing cold air due to a clogged condenser. Dust and leaves gather on the surface of the condenser causing condenser blocking and air obstruction. So, a blocked condenser will not dissipate much heat resulting in warm/weak cooling.

4. Faulty Condenser Cooling Fan

Condenser Cooling Fan
Condenser Cooling Fan

The condenser cooling fan sits on the condenser. It makes the refrigerant cool when the refrigerant flows in condenser tubes. A faulty condenser cooling fan is a major reason for car AC not blowing cold air when hot outside.

Some condenser releases heat by the natural flow of air while driving and alternatively, some do it by a condenser cooling fan. A faulty or dead condenser cooling fan will not run and dissipate enough heat from the condenser. Hence, the car AC will not blow cold air when hot outside. So, make sure you have a good working condenser fan.

5. Clogged Expansion Valve Or Orifice Tube

Expansion Valve
Expansion Valve

A blocked expansion valve or orifice tube is also a common reason for a car AC not cooling enough.

The expansion valve and orifice tube convert refrigerant from liquid to vapor state. When metal particles accumulate in the expansion valve, they cannot operate fully in an excellent way. Therefore, the valve remains stuck in an open or closed position causing the car AC to not blow cold air.

6. Moisture In The AC System

Moisture is the common reason for car AC blowing warm air while idling. It is the poison of the AC system. It can react with lubricating oil and forms formic acid, which slowly deteriorates the whole AC system’s performance. So, a moisturized air conditioning system will not cool the car properly.

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7. Clogged Evaporator

Clogged Evaporator In Car AC
Clogged Evaporator In Car AC

Unlike, the condenser that releases heat from the refrigerant, the evaporator adds heat to the refrigerant. It works oppositely as the condenser does.

The evaporator absorbs the heat from the inside of the car and makes the interior air cool. A blocked or leaked evaporator will not fully remove heat from the cabin air. As a result, hot air will blow out of the vents.

8. Overfilled With Refrigerant

AC Overcharge With Refrigerant
AC Overcharge With Refrigerant

Overcharging is also a usual reason for car AC not cooling in hot weather. Refrigerant overloading can increase the pressure on the low-pressure side by liquid running too far into the evaporator.

This phenomenon makes the low-pressure side a low-sucking side. This decreases the cooling performance of the car AC and eventually, the car AC will not blow cold air.

9. Dirty Cabin Air Filter

Clogged Air Filter Of Car AC
Clogged Air Filter Of Car AC

A dirty air filter is a reason for car AC not cooling properly. It filters the debris and pollens from the air to make the cabin air clean and healthy. A dirty air filter will not let the air pass. Therefore, maximum air will not move across the evaporator, which leads to poor cooling of the car AC.

10. Worn Compressor Belt

Worn AC Belt Of A Car
Worn AC Belt Of A Car

A worn-out belt is also a common reason for car AC not blowing cold air. The serpentine belt has an important function in running the compressor.

The compressor consumes a lot of power from the engine. If the compressor belt is worn, weak, or loose by constant usage. The compressor belt will slip, and will not rotate as it should, forcing the AC not to blow cold air.

11. Overheated Engine

Overheated Engine
Overheated Engine

An overheated engine is also a big factor in car AC not cooling. In an overheated engine, too much heat produces, which affects the cooling capacity of the condenser cooling fan. As a result, the car AC will not blow cold air properly.

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Frequently Asked Questions (FAQs)

Why does my AC get warmer at idle?

There are a few reasons why your AC might get warmer at idle. One reason could be that the compressor is not getting enough power, which can happen if the engine is not running at full capacity. Another possibility is that the condenser is not getting enough airflow, which can happen if the car is not moving or if the airflow is obstructed. Finally, it could be that the refrigerant level is low, which can cause the AC to work less efficiently.

Why does my AC only get cold when I drive fast?

The reason your AC only gets cold when you drive fast is that the airflow over the condenser coils is insufficient. This means that the coils are not able to properly cool the air, resulting in warmer air being circulated into your car. driving faster creates more airflow, which helps to better cool the coils and results in colder air being circulated into your car.


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