Auto A/C Repair

It’s rare to find an automobile these days with no air conditioning system. The A/C system has become a complementary part of an auto, and it is like we can no longer imagine a car not having its own A/C. Like the other parts of the automobile, the A/C is used a lot. This means that it can also get broken and need some fixing.

Before we tackle problems we may encounter with our auto A/C systems and how to fix them, let us first familiarize ourselves with how the auto A/C generally works. To make it easier or those who aren’t really into cars, just picture your auto A/C as a refrigerator inside your car.

How A/C Works

Start at the Compressor…

The first component that is vital to the system is the compressor, which is also considered as the heart of the A/C system. It is run by an engine belt, and has an electrically operated clutch that turns the compressor on and off. It is the compressor that puts pressure on the refrigerant or gas, compressing it. The compression will make the gas hot, and so the refrigerant will be carrying heat as it is sent to the condensing coils that can be usually found in front of the radiator.

From Compressor to Condenser…

The condenser then changes the state of the refrigerant it receives from the compressor. It is like a miniature radiator mounted next to the big radiator in front of your car. The condenser may have an electric cooling fan of its own; you can check your car if this is so. The main task of the condenser in the A/C system is to change the refrigerant from gas form into liquid form. The gas is cooled until it becomes a liquid, and the heat that it had from the compression earlier is dissipated through the tubes. The liquid refrigerant is then sent through the expansion valve and into the evaporator.

From Condenser Through the Thermal Expansion Valve…

It is in the thermal expansion valve that the refrigerant loses the pressure that was given it back in the compressor. It also meters the flow of the refrigerant liquid and atomizes it. At this part, some of the liquid turns into low-pressure gas as the remaining liquid is cooled down. The expansion valve then continued to control the flow of the cool refrigerant onto the evaporator.

And Onto the Evaporator…

With the cool refrigerant, what’s left is to generate the cold air we need to cool the car. The evaporator does just this by forcing air through into the car as very cold liquid pass through the tubes of the A/C system. It is like the radiator, only it does the opposite of what the condenser does. The cool air that is forced out by the evaporator is the cool air that goes into the car to offer its occupants a refreshingly cool trip. When the refrigerant liquid starts warming up again, it will turn back into gas form. This refrigerant gas will then be sent back to the compressor where the whole cycle goes again.

And the Receiver-Drier…

There is also the drier, or accumulator, or receiver-drier,  which acts as a filter and removes moisture and other contaminants from the refrigerant. It also makes sure to catch any liquid left from the evaporator before it  lows round back to the compressor and damage it. The drier absorbs this liquid and/or water moisture in the system by using a dessicant. The drier also actually has a filter that can catch anything that might be in the system and shouldn’t be.

A/C Problems and How To Repair

Refrigerant Warning:

Before anything else, be warned that venting refrigerants is ILLEGAL. The refrigerants used in the past have been proven to be dangerous to our ozone layer. The refrigerant R-134a is what is used now. Make sure that you have had your car checked and converted to using the R-134a for your A/C system. It is recommended that you have a professional mechanic do this process instead of trying to fix it yourself. There are certain government protocols that need to be followed when converting to R-134a.

If you have a R-134a leak on your A/C system, it is also recommended that you take the problem to a repair shop and a mechanic. Spotting a leak is easy for mechanics, and auto shops usually use fluorescent dye to check for leaks. Fixing it is a somewhat different matter. Fixing a leak is complicated and should be left up to the professionals.

No Air Coming Out of the A/C Vents:

If you notice that there’s no air coming out of the vents, check the air conditioner fuse and see what’s wrong. Replace it if necessary. If the problem is not with the fuse but rather that your air conditioner system is discharged, go to an auto repair shop or a mechanic to have the system evacuated and tested for leaks.

If the problem is that the air conditioner low pressure switch is defective, then replace the switch. If it’s the fan resistor pack that is defective, then replace the resistor pack. If it’s a loose connection, broken wiring, or a defective relay, then replace as necessary, too.

Warm Air and Not Cool Air:

See if the A/C system is discharged. If it is then have it evacuated, charged, and tested for leaks by a professional. If the compressor clutch is not engaging, then check the clutch wiring, the electrical connections, and the compressor clutch. Have it repaired or replace if needed.

There is Water Collecting on Floor When Using A/C:

The evaporator drain hose may be blocked. Check and clear it. If the drain hose is not blocked but disconnected, secure the hose to the evaporator drainage tray under the dashboard.

What Is That Moldy Smell?

If a moldy smell accompanies the air conditioner as it blows air, the evaporator drain hose may be blocked or restricted resulting in condensation build-up, and this creates the smell. Just clear the drain hose and it will be all right.