Why Is My Car Air Conditioning Not Blowing Cold Air?

 

If your air conditioning vents are blowing air but the air isn’t cold, the most common cause is low refrigerant gas within the system.

Your vehicle’s air conditioning system relies on refrigerant gas to remove heat from the air before it enters the cabin. As refrigerant levels reduce, the system becomes less effective at cooling, and eventually the air conditioning may stop producing cold air altogether.

The good news is that this is often a normal part of vehicle ownership. Air conditioning systems naturally lose small amounts of refrigerant over time, which is why most vehicle manufacturers recommend servicing the air conditioning system every two years.

However, before simply adding more refrigerant, it is important to understand why the refrigerant level has reduced and whether the system is functioning as it should.

 

Does Low Air Conditioning Gas Cause Warm Air?

 

Yes.

If there is insufficient refrigerant gas in the system, the air conditioning will struggle to cool the air passing through the evaporator.

In the early stages, you may notice the air conditioning is not as cold as it once was. As refrigerant levels continue to reduce, the air may become only slightly cool or eventually feel no different from the outside temperature.

This is one of the most common reasons drivers experience poor air conditioning performance.

 

How Often Should Car Air Conditioning Be Serviced?

 

Most vehicle manufacturers recommend servicing the air conditioning system every two years.

This is because air conditioning systems naturally lose small amounts of refrigerant over time, even when there are no faults or leaks present. As refrigerant levels reduce, cooling performance gradually decreases.

For this reason, if your air conditioning is no longer blowing cold air and has not been serviced for several years, low refrigerant levels may simply be the result of normal refrigerant loss rather than a fault within the system.

However, if the air conditioning has recently been regassed and cooling performance is lost again within a short period of time, this may indicate a leak within the system and further investigation will be required.

 

How Do I Know If My Air Conditioning Has A Leak?

 

The only way to know for certain is to test the system.

Air conditioning systems are designed to be sealed, so whilst some refrigerant loss over time is considered normal, a significant loss of refrigerant over a short period may indicate a leak.

Leaks can occur from pipework, seals, condensers, compressors or other components within the system. Some leaks are obvious, whilst others can be extremely small and difficult to identify without specialist equipment.

This is why a proper air conditioning service involves more than simply adding refrigerant gas.

 

What Happens During An Air Conditioning Regas?

 

A professional air conditioning service begins by recovering the refrigerant currently inside the system.

The amount recovered is measured and compared to the manufacturer’s specified quantity. This provides an indication of how much refrigerant has been lost since the system was last serviced.

Once the refrigerant has been recovered, a vacuum test is carried out. The system is placed under vacuum and monitored, typically for around ten minutes, to check for any major leaks.

This process is designed to identify significant leaks before new refrigerant is introduced back into the system.

If the system fails the vacuum test, the regas will not be completed and further investigation will be required to identify the source of the leak.

If the system passes the vacuum test, the correct quantity of refrigerant is added before the air conditioning system is tested to ensure it is operating correctly and producing cold air from the vents.

 

Why Won’t A Garage Regas An Air Conditioning System With A Major Leak?

 

Refrigerant gases are controlled substances and can be harmful to the environment if released into the atmosphere.

For this reason, it is not appropriate to repeatedly regas a vehicle that has a significant leak without first addressing the underlying fault.

The vacuum test is designed to identify major leaks before refrigerant is added back into the system. If a major leak is detected, further diagnosis is required before the air conditioning system can be returned to normal operation.

 

What Is UV Dye And Why Is It Added During An Air Conditioning Regas?

 

During an air conditioning service, a UV dye is commonly added to the refrigerant system.

The dye circulates with the refrigerant and can help identify small leaks that may not be apparent during the initial inspection.

For this reason, it can be beneficial to return to the garage one to two weeks after the regas for a UV inspection. This gives any small leaks time to leave traces of dye around the source of the fault, making them easier to locate before the dye has had an opportunity to spread throughout the surrounding area.

 

What Air Conditioning Gas Does My Vehicle Use?

 

Most vehicles in the UK use one of two refrigerant types:

• R134a
• R1234yf

R134a is commonly found in older vehicles, whilst R1234yf is used on many newer vehicles and has a lower environmental impact.

The type of refrigerant required depends on the vehicle manufacturer and the system must always be filled with the correct refrigerant specified for that vehicle. 

In many cases, you can identify which refrigerant your vehicle uses by checking the information label located under the bonnet. This label will typically state the refrigerant type and the quantity required for the system.

If you are unsure, don’t worry. Your garage will be able to identify the correct refrigerant during the air conditioning service.

 

Summary

If your car air conditioning is blowing air but not producing cold air, low refrigerant levels are one of the most common causes.

In many cases, this is simply due to the natural loss of refrigerant that occurs over time, which is why manufacturers recommend regular air conditioning servicing.

However, if cooling performance is lost shortly after a regas, or the system is found to have insufficient refrigerant again within a short period, further investigation may be required to identify a leak or underlying fault within the system.