If your car's air conditioning is on the fritz, it can be hard to decide which shop to take it into. A simple Google search will show you more auto repair shops than you can shake a stick at. How do you really know who you can trust?

A good air conditioning repair can be hard to find, that's because most air conditioning repair is hard to diagnose. Unlike other parts of your vehicle there are no “check air conditioning” light or some computer module that can tell you exactly how it is performing. So that leaves two options, the guess and check method or using sophisticated and expensive machines, such as an automated recovery and refill unit with a leak detection system. The good news is Bob's Main Street Auto uses such machines. The alternative is what many other shops do, and that is to make the best guess as to where the problem might be, fix or replace the component and see if they got it right. If they guessed right the first time, your bill might be low. If it took a few guesses to figure where the problem was….. well your bill might just shock you.

So how exactly does the a/c in your car work? Well simply put it's kind of like a radiator. The compressor pumps the refrigerant through the system (which at this point is a gas) it compresses it into a high pressure state causing it to get very hot. The high pressure refrigerant flows to the condenser where it flows through what is essentially a “radiator” and the air flowing past it cools the gas, condensing it into a liquid. Hence the name condenser, it then travels to a thermal expansion valve or in some cars it's called an orifice tube. This valve or tube only allows a small amount of refrigerant through at a time and releases the pressure that has built up from the compressor. When the pressure is rapidly reduced it causes the refrigerant to become very cold. The very cold (now low pressure) refrigerant travels to the evaporator. Which is basically another radiator, however this time it's the air being cooled by the a/c system and not a/c unit being cooled by the air as in the previous step, a fan blows air past this “radiator” which you then experience as nice cold a/c. At low pressure, the refrigerant has a boiling point of 15 degrees below zero so hot summer air causes it to evaporate again (which is why it's called an evaporator).  From here the refrigerant goes to the Accumulator or in some cars a Receiver/Drier. Both perform the same function and that is to filter the refrigerant and absorb any moisture in the system. After this, the whole process starts over again and travels back to the compressor.

If this whole process seems complicated; it can basically be summed up in a few short sentences. Your refrigerant gets compressed, it heats up. Then it cools down and gets decompressed and it gets very cold. A fan blows air past the very cold refrigerant and voila! You have cold air blowing in your car.

Understanding how you're a/c works can help you with understanding what happened if it stops working. With the exception of the compressor there really aren't many moving parts, and you can't use up refrigerant or wear it out so theoretically it could last forever.  However a broken a/c is usually caused by a leak somewhere in the system. This can happen in some of the rubber components or even the metal parts themselves. Even the smallest of leaks will eventually lead to your car not blowing cold air. Which brings us all the way back to why it's important to take your vehicle to a repair shop that has the right tools to find the problem and fix it right the first time.  So if your car isn't blowing cold a/c any more feel free to call or stop on in at Bob's Main Street Auto.


Air Conditioning