Automotive AC Service and Repair Basics

It’s summertime here in the valley, and your cars air conditioning has been working overtime for several months now.  If we haven’t heard from you yet, chances are pretty good your AC is doing an OK job.  But let’s talk about the question everyone likes to ask once August rolls around here in Mesa AZ – Does my auto AC need service?  It’s easy for your car’s air conditioner to keep up when it’s below 100 degrees out, but what happens when the thermometer or even the hygrometer (Google this fancy word!) maxes out?

First off, let’s go over some basic terminology so we can better explain how your AC functions. There are five key components to any air conditioning system:

Refrigerant: The Lifeblood of Your Air Conditioning System

Most newer vehicles use R134a which is a relatively safe and easy to handle gas. This gas is the lifeblood of your air conditioning and it is very important to notate here, that newer vehicles are very sensitive to the refrigerant level. Most newer vehicles contain 16 oz or less of R134a, and being even slightly over or undercharged can wreak havoc on your AC.

Compressor: Turning Refrigerant Gas Into Liquid

The air compressor is responsible for compressing your refrigerant from a gas into a liquid. It is typically run by your engine via a drive belt or serpentine belt. Many newer vehicles are using electric AC compressors that are not driven by the engine and can be run with the engine off. This is particularly beneficial with hybrid or electric vehicles.

Condenser: The Radiator For Your AC System

The condenser is in the very front of your vehicle (right behind the bumper), and is responsible for dissipating the heat from your refrigerant once it has been compressed into a liquid. A quick chemistry break here – compressing any gas into a liquid results in the production of heat. Heat is obviously the enemy here, so it is the job of the condenser to get rid of it. The condenser can be thought of as the radiator for your air conditioning.

Expansion Valve: Converting Refrigerant Liquid Back to Gas

The expansion valve (or orifice tube, as used in some older vehicles) is responsible for converting your liquid refrigerant back into a gaseous state. Going back to our chemistry break, as a liquid is converted back to a gas it cools. Think of how much cooler a freshly watered lawn is than the Phoenix asphalt on a summer day. This temperature difference is caused by the evaporation of water, the same theory holds true with your air conditioning. The expansion valve is no more than a fancy device that forces the liquid to evaporate into a gas and this is where the magic happens.

Evaporator: A Tiny Radiator

The evaporator is a small aluminum box that is typically located under your dash. The freshly evaporated refrigerant travels through the evaporator and is dissipated into the interior of your vehicle. You must also picture your evaporator as a tiny radiator, air is forced over it (by your blower motor) and then through the vents, and onto your happy face.

When Does My Vehicle’s AC Need To Be Serviced?

Now that we’ve got the technical jargon down, let’s move on to the original question – when does my auto’s AC need to be serviced? The short answer is simple – If your car is six years old or older, it is likely noticeably low on refrigerant.

Even a properly functioning AC with no visible leaks will lose small amounts of refrigerant. This is due to the fact that your AC may be operating at refrigerant pressures well over 350 psi in the heat of the summer. This pressurized liquid will slowly escape through your air conditioner’s rubber hoses and sealing O rings.

Why Shouldn’t You Use a DIY AC Recharge & Service Kit?

The simple answer is that they are an inaccurate and sometimes unsuitable solution to recharge your car’s air conditioner . But here are a few more reasons why:

1. The only true way to know exactly how much refrigerant is in your system is to completely recover the old refrigerant, and recharge it with the precisely recommended manufacturer’s capacity. When you use the do-it-yourself kit, you are just topping the system off.
2. By just topping the system off, you are essentially guessing. The do-it-yourself kit relies on a gauge that reads the pressure on the low side of your vehicle’s AC. While this is “close,” it is definitely not precise.Your system’s pressure can vary greatly, depending on the ambient temperature outside, and even the temperature of your vehicle. So by guessing, you can potentially overcharge or undercharge your vehicle’s AC, and either situation can dramatically decrease the life of your air compressor. An overcharged system can cause your compressor to turn on and off excessively, and also potentially damage components due to the sheer pressures we are talking about. I have seen a couple cases where an AC compressor has actually exploded! In the case of an undercharged system, your AC compressor cannot be properly lubricated. You see, it is also the job of your refrigerant to transfer the AC oil through the moving parts of your AC compressor. When this does not happen, your compressor will end it’s life at an undesired time.
3. Some do-it-yourself kits contain “stop leak.” Now I don’t know who came up with this, but it is absurd. Stop leak is a very nasty substance that will gum up your AC system and eventually stop the compressor from being properly lubricated.
4. When you recharge an AC system, you must also add the proper amount of oil. Yes, do-it-yourself kits do contain oil, but who knows how much is making it into your system. Too much or too little will damage your compressor.

How Do You Service Your Car’s AC in Mesa, AZ?

Short answer – take it to your mechanic! We invest in state of the art (see: very expensive) air conditioning machines, and will recover and properly recharge your system with the precise amount of refrigerant and oil.

This is the only way to do it right with today’s sensitive systems. This will ensure a long-lasting, trouble-free operation. And remember, most auto AC services are under $200. It can cost upwards of $2,500 to replace a damaged AC compressor. So what are you REALLY saving by doing it yourself?  Let the professionals service your car AC.

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We’ve put together this very easy to read and understand infographic that you can share on social media or print off for your own reference.