96/98 Cecil StreetWD24 5AP

MOT Garage Watford

Vehicle Diagnostics, Servicing and Repair

Phone Number: 01923 239460

Mobile Number: 07850 359668

Signs Your Car Air Conditioning Needs Servicing

  • Posted by:
  • Admin
  • Tags:
  • Posted date:
  • 08-08-2022
Signs Your Car Air Conditioning Needs Servicing

Find out how to tell your car air conditioner needs repair. We look at the signs your car air conditioning needs servicing.

Air conditioning and HVAC systems are surprisingly important components of most cars. Not only does it help your car remain cool in extreme heat and the summer months and warm in the winter, but it helps you to demist your windscreen to help you drive safely.

While most drivers may consider it a luxury you can afford to lose from your car's air conditioner system, you'd definitely miss it when you're stuck in a traffic jam on a hot day. Air conditioning can also affect your car's performance, saving you money on fuel and reducing the need for car A/C repairs. 

So this begs the question: when was the last time you had your car's A/C serviced? Many people having their car serviced don't realise that A/C services aren't included and that you have to arrange for separate checks to be carried out. As a general rule, most manufacturers recommend that you have your air conditioning system serviced and replaced at least every two years.

However, there are signs to look out for that indicate you might need to do this sooner. Here are some of those tell-tale signs. 


How To Tell Your Car Air Conditioner Needs Repair

The air isn't cold

If you notice that while your air conditioning system may still be functioning, but the air you're getting isn't cold enough to keep you comfortable, you may need to recharge or top up your refrigerant.

This may be quite tricky to notice, especially if you don't use your car A/C that often. But it will be a nasty surprise when you come to turn it on during the summer, only to find it not cutting the mustard.

Bad odour

When you turn your car A/C system on in your car and notice a bad smell from the vents or cabin air filter, this is a sign that your air conditioner system needs a good clean.

Through years of use, it's not uncommon for bits of dirt and dust to clog up your air conditioning system, which can lead to a build-up of bacteria. Like any mould or mildew growth, this can lead to foul odours coming through the airflow.

Weak or no air coming out

If there is a weak flow of cold air coming from your A/C or no air at all, this can be a sign of a leak somewhere in the car air conditioner system, preventing it from working efficiently. 

Leaks are mainly caused by the age of your system and the components wearing out or moisture.

The rubber used in the lines of most car air conditioning systems degrades through time and exposure to heat and moisture.

Once the seals or hoses degrade enough, the refrigerant will leak from the air conditioner system.

Weak airflow problems might also be a more serious sign of a compressor malfunction, so if you notice an issue, it's always best to have it inspected by a professional.

How To Tell Your Car Air Conditioner Needs Repair

Rattling sounds

Rattling is another common sign of an issue with your air-con system. Usually, it's caused by a loose condenser or fan belt becoming worn out.

Alternatively, it could mean that there is debris blocking the system. The latter will usually show itself in other ways, too, such as condensation on your dashboard or it taking longer for the cold air to come out.


Again, if you notice any condensation around your dashboard, it's a clear sign something is wrong with your air conditioning system. As you can imagine, car air-con systems are fairly complex, with many components needed to keep them working, including the refrigerant, evaporator, compressor and condenser.

The refrigerant is changed from a gas into a liquid and back again in order to cool the air in your car. Therefore, condensation is a sign of water or liquid dripping from somewhere in the air conditioner system. If there is enough moisture leaking from the system, it could lead to damp.

Burning smells

Along with bad odours, you may also notice burning smells under your bonnet if there is a serious issue with your air conditioning system requiring major repairs. In this case, there are several things you should check, including:

Cooling fans

Refrigerant leaks

Coolant leaks

Electrical wiring

Car A/C clutch failure

Car A/C compressor failure

Pulley bearing failure

Serpentine belt broken or loose

Engine overheating  

Alternatively, if you notice the burning smell coming from your air-con vents, it's more likely to be an issue with the blower. You will need a professional to check whether it's the blower motor, electrical connectors, or a blower motor resistor.

Increasing temperature

A very strange and noticeable issue is when you turn your air conditioning on, allowing it to cool your car, only for it to heat up a few minutes later.

This is a fairly simple issue that is mostly caused by internal clogs or restrictions. It's also a simple fix, with the hoses and lines simply requiring a clean.

Alternatively, it could be something more serious, requiring an equally serious fix. In cases such as these, you'll most likely have to replace your A/C compressor or other essential components.

Car Air Conditioner Servicing

Immobile compressor clutch

There should be a distinct sound when you turn your air conditioning on in your car. This is the sound of the compressor clutch engaging. If you don't hear this noise, it's a sign that your refrigerant charge could be too low, meaning the system isn't working properly.

It could also signify that your compressor clutch has seized through wear or debris build-up or that it is stalled or broken. Whatever the reason, your compressor cannot draw power from your engine. To remedy the issue, you'll either need to replace the A/C compressor clutch or the entire A/C compressor clutch assembly.

This isn't as complicated as it sounds, and you can call out a mechanic to perform the car repair while it is in your driveway.

Leaking under the dashboard

Noticing a leak by your feet in the footwell or anywhere underneath your dashboard is another sign there could be a potential issue with your car's air conditioning system. Reasons for a leak such as this include a blockage in the vent hose or evaporator drain, which would prevent any condensation accumulated within the evaporator case from escaping.

Alongside a leak, you may also notice your A/C blowing hot air instead of cold. This is due to the heater core leaking coolant, causing your car to overheat. A broken heater core will require immediate fixing and potentially expensive repairs as it will cause significant damage through bacterial growth.

Leaky refrigerant

Refrigerant is the most crucial fluid in your air conditioning system, as it is this fluid that creates the cool air to keep your car at a comfortable temperature. Therefore, when it leaks, it can cause serious issues. Refrigerant is usually a greasy, thin substance that usually has a fluorescent tinge thanks to a leak dye.

You'll most likely notice it around your air conditioning hoses, lines or the major A/C unit. But leaking refrigerant isn't just an issue for your temperature control; it can also ruin your fuel economy and is incredibly harmful to the environment.

Overactive A/C clutch

Other strange noises to listen out for are your A/C clutch engaging and disengaging quickly while your air conditioning is switched on.

This is a sign that you have a low refrigerant charge. Having a low refrigerant charge will mean your compressor cannot pressurise, so you will need a professional mechanic to recharge it.

Otherwise, you run the risk of wearing out your A/C clutch prematurely. 

signs your car air conditioning needs servicing

How to Maintain Your Car's Air Conditioning

The best way to keep your car's air conditioning system in working order is to have it serviced by an air conditioning expert at least once every two years, if not more. As part of a car air conditioning service, you'll want to make sure your mechanic checks the following components:



Drain Lines


Operating Pressure

Operating Temperature

Return Lines

Supply Lines


Refrigerant Levels



Having a professional recharge your car's air conditioning

Of course, you could always attempt to recharge your car's air conditioning yourself, so long as you know what you are doing. If you don't, then having a professional carry out the procedure is best. It will cost you roughly £50 to complete this, and it will usually only take around an hour to complete.

Professionals also know how to safely evacuate any refrigerant gas from the air conditioner system, which is something you won't be able to do yourself. 

Most garages or air conditioning specialists will have the skills and equipment necessary to carry out a recharge. They will have the expert knowledge required to know how much refrigerant your car requires, given that different car makes have different air conditioning systems. They will also know the specific mixture of lubricant and gas required to preserve the moving parts of your car's A/C compressor to keep your seals moist and operational.

If you require annual servicing, choose a garage that you can trust. Follow the link below to contact a car service mechanic in Watford.