Common Air Conditioning Problems and Solutions

Not having a fully working air conditioning system in your vehicle on a hot summer's day can make even the shortest car trip unbearably stuffy and uncomfortable. 

First, let's look at how an automobile's air conditioning system works, then identify the most common air conditioning problems and offer solutions to fix them, helping you keep your cool behind the wheel. 

How Does a Vehicle's Air Conditioning System Work?

A vehicle's air conditioning A/C system comprises five main components: the compressor, condenser, receiver, thermal expansion valve and evaporator.

Compressor

This part is the heart of the A/C system that pressurizes the refrigerant to cool the air.

The compressor also senses temperature variations between the inside and outside of the vehicle while controlling temperature output. 

Condenser 

This radiator-like part is typically found in front of the car's radiator, reducing the temperature and pressure of hot gasses from the pressurized refrigerant. 

Accumulator/Receiver or Dryer

The type of system depends on your vehicle; you may have an accumulator or a receiver/dryer. The function of this part is to separate the hot refrigerant gas from the liquid while removing any damaging moisture from the system.

Thermal Expansion Valve

This valve, fitted between the condenser and evaporator, monitors both pressure and temperature in the A/C system. The valve calculates the precise amount of refrigerant that can safely go into the evaporator for the cooling function. 

Evaporator

The evaporator found under the dashboard's primary function is to cool the air using the pressurized refrigerant from the compressor. The fan and air vent system blows the cooled air into the vehicle's cabin. 

Common Problems and Suggested Fixes

Here are some commons and how these are fixed. 

Refrigerant Leak

A leak in the pressurized A/C system leading to refrigerant loss is one of the most common problems encountered with the air conditioning in your car. 

Leaks will occur more in winter than summer due to the A/C system typically seeing little use in cold months. Seals dry out from nonuse causing refrigerant gas leaks.

A leak in the refrigerant line can be difficult to detect, but leaks are typically at the hose connections. A visible oily substance around a connection is a sure sign of a refrigerant leak. 

The fix may be as simple as tightening up the connection itself. However, faulty or damaged threads may necessitate repair by a technician or the connections and pressurized lines will require replacement at a suitably equipped workshop.

Blocked Condenser

As we learned above, the condenser of the A/C unit cools the hot compressed refrigerant by blowing airflow through the front of the car when on the move. Debris can easily block the condenser affecting its ability to cool effectively. A sure sign of a badly blocked condenser is warm air entering the cabin. 

This issue should be an easy DIY fix by inspecting the grill and checking for clogging. Removing any debris should allow the normal functioning of the air conditioner.

Broken Condenser

More serious than a simple blockage of the condenser, a broken unit will not allow the A/C refrigerant to recool with a high chance of leakage. If checking the condenser reveals nothing blocking it, this can point to a broken condenser. The condenser consists of numerous seals and tubes, which will deteriorate over time-Discovery of any oily, greenish residue on the condenser points to leakage from a breakage.

Puncture of the tubes by road debris is a common cause of failure, and the only recourse is to replace the condenser using the services of suitably qualified workshops.

Electrical Issues

The A/C system is composed of mechanical and electronic systems, and faults in the electrical system and wiring will affect the air conditioning unit causing incorrect functioning.

A quick check for loose connectors, blown fuses or frayed wires may be within the ability of a DIY mechanic. Most modern vehicles with more sophisticated automatic climate control features with digital touchscreen interfaces will pose a challenge. 

Repairs to these systems will require a certified auto electrician or suitably qualified workshop technician to identify the issue and repair if nothing obvious is visible. 

Any electrical fault should be treated as a potential fire hazard, so a repair should be made sooner rather than later.

Faulty Fan

Electrically controlled fans move cooling air through the condenser, and a faulty fan will lead to your car's A/C not functioning 100 percent. A quick look under the bonnet is easy to determine whether the fan is moving properly. The cooling fan may not work due to road-accumulated debris, a faulty fan temperature switch, blown fuses, or electrical issues.

The faulty fan should be repaired or replaced at a suitable workshop facility. 

Bad Compressor

As the heart of the air conditioning unit in a vehicle, a bad compressor will cause the A/C to fail to blow cold air into the cabin.

A common cause of compressor failure is that if not being used regularly, the compressor and or compressor clutch is put under immense strain or shock when turned on again. Running the A/C every few weeks during the colder winter season is recommended to prevent this from happening. 

Identifying a bad compressor or defective clutch is easy enough, with loud noises coming from the compressor when switching on the A/C being a sure sign that all is not well. Broken internal components or any seized bearings will cause high-pitched noises. 

A technician or a suitable workshop facility must repair or replace a faulty compressor.

Have Your Vehicles A/C System Serviced or Repaired at Granite Subaru 

Ensure your Subaru or any other car manufacturer's A/C is working at its best by contacting our service center at Granite Subaru. Equipped with the right specialized tools, we will ensure your vehicle receives the quality service or repair you expect from Subaru.

You'll receive the service expertise of Factory Trained Service Teams trained to high standards by Subaru's technical instructors.