car ac service

How a Car AC Works

Let’s get some insight into what makes a car AC function  & the components. Starting with the-

Compressor

Compressor is responsible for compressing the refrigerant gas. The compressor works like a pump that pressurizes the refrigerant gas and passes it on to the evaporator. The drive-belt drives the compressor also power steering and water pump etc.

Refrigerant gas

The refrigerant gas is a fluid that is contained within the coils of a car AC system that makes the whole cooling thing possible. The most common refrigerant gas used in Car AC system is the R134-a, also known as Tetrafluoroethene. Before 1993, the most widely used refrigerant gas was the R-12 a.k.a Freon. its quickly replaced Freon into r134a since it harmed the environment. 

Condenser

A condenser is a mesh of coils. They arrange these coils in a zig-zag pattern to easily remove the heat from the compressed gas. It acts as a heat exchanger which cools the refrigerant gas by changing its state from gas to liquid and gas looks like cool

Evaporator

The evaporator or cooling coil is quite opposite of a condenser. It converts the liquid refrigerant gas back to its gaseous state. It at the same instant/moment dissipates the heat and further cools it down. The evaporator or cooling coil is located inside the car. The manufacturers typically place it behind the car dashboard.

Expansion Valve

The expansion valve works in tandem with the evaporator or cooling coil. It controls the pressure of the AC refrigerant gas through the AC system.

Dryer/Accumulator

The dryer unit contains a desiccant. It is responsible for pulling away moisture that can seep into the AC system like Evaporator, Condenser and the pipes.

 Top 10 Reasons that your Car AC is not Cooling Enough

Turn on the blower, push the AC button and enjoy the cool and comfortable air.

Well, there is more to it than that. When you switch on the AC system, the compressor running on using some power from the engine. It then compresses the refrigerant gas present in the AC system causing it to liquefy.

The liquified refrigerant gas then travels to the condenser. This then pulls the heat using condenser system out using fresh air assisted by a fan. Afterwards, the refrigerant gas flows through the expansion valve where the pressure is checked and regulated.

Further down the line, the dryer pulls out moisture or impurities from the ac system. The now cool and clean gas is passed through the evaporator or coolimg coil fins where a blower fan pushes the cold air out of the dashboard vents. The refrigerant gas is then pulled back to the compressor where the cycle starts all over again

When you take your car for a car AC service, the technician  checking the cabin temperature while operating the car AC. It should be approximately 5°C-10°C. They would then proceed to check the level of the refrigerant gas present in the system.

When the refrigerant level drops it affects the AC ability to cool. In fact, one of the most common reasons why the air-conditioning isn’t cooling your car properly is this. Using a pressure gauge and a precision AC gas recharging machine, they flush the refrigerant gas out and tops it up to the recommended level or bubbles in pipe line disappear.

While working on this, they also check if there is any possible leak or crack in the AC line and hoses. The technician may use a UV dye to better check potion of a possible leak in the ac system.

Then they come into the compressor, which is the most expensive and important component in a car AC system. It is check power of compressor or leak  etc. If the compressor malfunctions, the whole AC system will fail or working low cooling.  So, if there is a visible leak it could be because of a bad seal and bearing. The compressor making  noise while operating could point to the same thing. The best way to keep a compressor working is to get it checked out and service every year. Also, make sure to get them to replace the compressor oil recommend by manufacturer

The condenser, which resides in front of the engine is checked for bent/damaged fins or a clogged line. A condenser becomes clogged due to leaves, dust and debris on it. It can also really bring down the cooling efficiency of the AC system. If such is the case, the condenser is washed with mild water pressure so as to not bend the fins or line

Furthermore, make sure that the dryer is properly functioning. They also do a final inspection of the evaporator for any moisture build-up. The moisture build-up is not good news. This is because the water content can seep into vital electrical components under the dashboard.

Finally, they clean the cabin filter  (heating, ventilation, air conditioning) located under the cabin box. After every tune up or change oils the filter is replaced.

Common Car AC Problems (with Troubleshooting)

Car AC not cooling enough

This can be due to low refrigerant gas level or a failed compressor, which can be quite expensive to fix it. Another reason for this is, something as easy as a clogged into condenser. If the condenser becomes clogged it decreases the surface area of the coil and this results in less cooling in ac system.

Bad odour from the AC

The reports of this cars AC problem are common. A faint or strong foul smell would point to mould/mildew or moisture formation in the AC filter. Cleaning or replacing the cabin filter usually solves the problem.

But if you smell “rotten eggs” while operating the AC, there can be pest invasion or a dead animal somewhere in the system. We strictly recommend you to get a professional to handle this.

Loud whirring noise

Loud high-pitched whirring noise while operating the AC  system can be due to a shot compressor bearing in case the noise is coming from the engine . But, if the noise is coming from inside the cabin, the blower fan assembly needs to repair or a replace.

Water seeping inside the cabin

When the refrigerant gas flows through the evaporator, it become the condensed. This forms water. If the drain tube which directs the water to the outside becomes blocked by dust, you may notice water inside the car floor.

Engine overheating

Just like the steering system or the water pump,  compressor uses some power from the engine (using the serpentine belt). The clutch on the compressor can seize causing the compressor to put an unnecessary load to engine. This eventually overheats the engine and make bad impact on engine gasket

Wipe the vents

Did you know, all that dust on the AC vent after a period of time accumulate . It can then clog-up the cooling coil or evaporator causing a drop in cooling. Using a brush or a sponge and gently clean the AC vent every week .

Clean the cabin filter

The cabin filter or the HVAC filter located behind the box can get dirty. The filter can clog due to dust and debris from the outside air. Like we said before, moulid and mildew can also form. This can lead to foul odor while the AC operates. You can easily service the AC filter using the brush. You can clean the fins with this. Spray a deodorizer before installation for better results.

Clean the condenser

The condenser is located behind the front bumper of the every car mostly . It is made of aluminum fins and line which take in the fresh air from fan. The fan helps the condenser to cool the flowing refrigerant system. Make a habit of hosing down  condenser with low-pressure water. This would dislodge the stuck leaves, debris or dust that can potentially affect the cooling of the AC system.