Why Is Your Car’s Air Con Not Cold?

Stepping out of the warmth of the day into a nice, cool cabin is unbeatable on those scorching days — just like a steady stream of cool air makes all the difference when you’re sat in traffic without shade.

But if all your air conditioning seems to do is blow hot air in your face, something must have gone wrong. Despite often being overlooked in car maintenance, air conditioning systems are deceptively complex with sophisticated components that require expert inspection and maintenance.

If your car’s cooling system has left you feeling red-faced recently, read on to find out just why this might be.

Checking your car’s air con

Your car’s air con health is not typically checked in a usual service and is not assessed during an MOT. Since air conditioning in a car is more of a comfort than a safety feature, mechanics will prioritise things like brake inspections and engine oil checks instead.

But that doesn’t mean your car’s air con isn’t important.

Book a Free Air Con Check with Kwik Fit today for a diagnosis of why your car’s internal climate is not cool anymore. It could be any one of the following reasons.

1. Your need an air con regas

As the most common reason for poor air-con performance, the level of charge left in your AC system is likely to be the culprit for all that hot air coming out of your vents. 

Your car’s air conditioning system is filled with refrigerant (not to be confused with coolant), which absorbs the heat from the air in your cabin, cooling it down. If your refrigerant levels are running low, then your air con system starts to become less effective at removing heat, resulting in a warmer air flow.

To solve this problem, you’ll need to undertake an air con regas procedure (also known as an air con recharge) where your refrigerant levels are topped back up. This can be a complicated process, so it is recommended that you get a specialist like Kwik Fit to regas your air conditioning system for you.

2. Your air con condenser is blocked or damaged

Your car’s condenser is a crucial part of your air conditioning system.

Working to convert the hot, high-pressure gas from the compressor into a cool liquid, the condenser is the element responsible for the cooling factor. Over time, dust and dirt particles can accumulate there, reducing the efficiency of the condensing process and eventually causing a blockage.

If this blockage is not addressed soon enough, it can cause damage to the condenser. When blocked or damaged, the condensed liquid is no longer able to be cooled effectively — hence the hot air. Every so often, it is advised you visually inspect the front of your car condenser for debris. You could even add this inspection to part of your regular car-cleaning routine to save yourself some time.

3. Your air con fans have failed

Another reason why your air con might be blowing hot is to do with the condenser fans. If the condenser’s fan motor fails, it can no longer help to draw air over the condenser coils, preventing heat from being released from the refrigerant. 

This, again, is caused by the accretion of dust and dirt in the condensing system, but can also be triggered by electrical issues like a blown fuse.

Even if the fan motor has not failed completely, it can still be damaged by collected debris, preventing the flow of cool air. Repairing fans can be a tricky process, so trust it to one of our professionals to get the job done.

4. Your air con’s refrigerant is leaking

Another common reason for a car’s air con to blow hot air instead of cold is leaking refrigerant.

Refrigerant is the low-flammability cooling fluid that maintains the pressure of your air conditioning system. A leak can occur anywhere across the whole system. If this happens, the pressure in the system drops and all elements underperform – especially the compressor.

Check for an oily liquid leaking in your air conditioning system but be careful not to touch any of the liquid as it can be extremely dangerous.

Sometimes, a leak can be fixed by placing sealant over the weakened area. However, occasionally all the refrigerant needs to be flushed out and replaced. For this procedure, we recommend you get in touch with your local Kwik Fit centre for specialist help.

5. Your compressor has failed

The element responsible for pumping the refrigerant around the AC system is called the compressor. If this fails, the overall pressure of your car’s cooling system will decrease, causing a noticeable drop in performance. Compressor failure can have a number of causes, but it’s usually:

• Leaking refrigerant
• Or an electrical fault in your vehicle.

6. There is an electrical fault

If your car’s electrical system is not working properly, your air conditioning doesn’t stand a chance. 

The core components of your air conditioning system — like the condenser fans and the compressor — all rely on electrical power to do their job. In the absence of a stable electrical supply to your AC system, it can’t work properly and will struggle to regulate temperature and pressure, resulting in poorer cooling efforts.

Blown fuses, switch failure, and a shorted blower control circuit are all possible culprits. While these issues are often minor and easily treated, if left unattended for long periods of time, more serious problems can occur such as acid buildup.

Get an air con regas & other services at Kwik Fit…

With one of our Free Air Con Checks, we can diagnose the issue with your air con in no time. If you’re struggling to keep cool in your car, get in touch with your local Kwik Fit centre today to find out about our air con maintenance services.