Case Studies

Automotive Air Conditioning Service – Myths, Magic and Mistakes

A Little Background
Air conditioning is one of those systems that has evolved over the years, and with it some old myths that have died hard. The days of the R12 (Freon) systems are nearly 30 years in the past, but I still here from time to time, the same myths and mistakes, chief among those is the “topping off” concept. This can be downright dangerous, if you buy the the flammable gas that is often sold in small quantities rather than the proper refrigerant.

The other thing I hear about is A/C  compressor failures, with no explainable cause. There are two general types of compressor failures, the first being electrical, which is a small subset, and other being mechanical. Almost every compressor failure occurs as a result of mechanical wear or damage, and almost always it relates to a lubrication failure caused by undercharging, or systems run low on refrigerant.

An Ounce of Prevention
I’ve authored this simple case study to explain how A/C has evolved from the “early days”, and the importance of thinking of preventive maintenance on the A/C system to prevent premature failures. We often think of A/C as system requiring no maintenance until it doesn’t work. That’s akin to ignoring brushing your teeth until you get a toothache, by then it’s often too late. You read how some small loss of refrigerant from a sealed A/C system is not only normal, but should be expected.

Myth 1 – “Topping Up” A/C Systems
The very first myth that needs to be addressed is “topping up” your system. Did you know that if your system is 10% low, you will lose 40% of your oiling capability to your A/C Compressor? You won’t experience lack of cooling until you have lost 40% of your refrigerant. During that time, from -10% to -40% loss of charge, you are doing damage to your compressor.

Problem is, your compressor does not have a sump like your engine does, it relies on the proper volume of refrigerant in the system to push the refrigerant oil back to the compressor. The compressor is one of the most costly parts in your vehicle’s climate control system, so therefore preventing problems should be the focus. The number one reason for compressor problems is caused by lubrication failures, most often the lack of refrigerant to move the oil around the system, in other words, an undercharged or leaking system.

Mistake – Why “Topping Up” Really Doesn’t Work
The problem with topping up your system is you don’t know how much refrigerant is in your system to add to it. There is no “dip stick” to indicate refrigerant charge. Back in the “old days“, vehicles had what were termed “sight glasses“, a small clear viewing port, often on the receiver dryer, that allowed one to see into the system, and to charge until no air bubbles were present. The sight glass went the way of the old R12 refrigerent systems, back in 1994.

Yet the myth persists, nearly 30 years later, that one can just “top off” the A/C system, like you top off brake fluid. Problem is, brake fluid is in a translucent container, refrigerant is not, you can’t see through the metal pipes and lines. When you add refrigerant to your system that is blowing warm you can increase the charge until the system starts to blow cold, but you may still be in the -10% to -40% low refrigerant range, which is still doing damage to your compressor by not providing proper lubrication to the system.

The Right Way
The only proper way to service your vehicle air conditioning is to recover the system, pull a vacuum to remove contaminants such as air and moisture, install refrigerant oil to lubricate the compressor, and then install the factory refrigerant charge as specified by the manufacturer. This requires a professional A/C service machine, which costs several thousand dollars, and some specialized equipment. The good news is that most A/C recharge services cost under $300, far less than a compressor replacement.

Little Cans Make A Big Difference

  • The current automotive refrigerant (R-134a) is a highly potent greenhouse gas.

  • Just the gas contained in one single 12-ounce container is equivalent to the carbon dioxide (CO2) emissions from burning 150 gallons of gasoline!

  • The gas from two 12-ounce containers, if released into the atmosphere, will cause the same global warming pollution as driving all the way across the country diagonally, from Los Angeles to New York.

Myth 2 – “Magic” Parts Store Recharge Cans – Buying Yourself A Can Of Trouble
The second myth is those “little cans of refrigerant” that are being sold at do it yourself parts stores. Federal Law states you can not sell refrigerant in containers that contain less than 22 pounds (10kg). If you are purchasing a container that has 6-12 ounces of “refrigerant” in it, this is often NOT R134a (refrigerant) which is required for your vehicle. What you are buying is called a Hydrocarbon, also known as a propane and butane mixture.

The way you can tell is to look at the labeling on the container, it will show the explosive and flammable symbol. R134a will ONLY show the compressed gas symbol on the label. R134a is not flammable or explosive, and is specified by the vehicle manufacturer for your vehicle. R134a and all proper refrigerants require technicians to be Federally certified to handle them. They are not available to be purchased without the proper certification.

A/C Fact – It’s Always Working – Even In The Winter

Here’s a surprising fact, your vehicle’s A/C never takes a break, not even in the winter. In fact your vehicles air conditioning system runs whenever you turn on the Defrost mode, and often runs when in the automatic mode.

The climate control system uses the a/c as it is designed to engage and act as a dehumidifier to remove the moisture from the air entering your vehicle to aid in removing moisture (fogging) from your windows.

You will notice vehicles with working air conditioning that the side and back windows are always clear. Vehicles without air conditioning or needing A/C repairs will have steamed up side and back windows which continually need wiping to clear.

Waiting Costs You Money
If your A/C system is not working 100% at the end of the summer season and you think you will get it fixed next year, do not put it off or you will do damage to your compressor. Remember, when you turn on the Defrost Mode, the compressor is engaged. With a low refrigerant charge over the winter months, you’re not getting the refrigerant oil back to the compressor which is damaging it all winter season that will lead to costly repairs in the spring time.

A/C Fact – A/C Service Is Normal – Think Every 3-5 Years
The Society of Automotive Engineers (SAE) designed the A/C fittings that are on your vehicle. These fittings have a SAE acceptable leakage rate of 1/4 ounce of refrigerant per year per fitting. That does not sound like a lot, but the average vehicle has 8 fittings. This means that you are losing 2 ounces of refrigerant per year.

So now that we know that you are are losing 2 ounces of refrigerant per year, and A/C service is just part of a proper maintenance schedule. It is recommended that you service your air conditioning every 3-5 years. This will ensure that your compressor is never “starving” for oil. The older vehicles used to have systems that held upwards of 36 ounces of refrigerant. Today’s vehicles have much smaller systems that require as little as 15 ounces of refrigerant. The need to service your air conditioning has become much more important with these reduced capacities or system damage will occur.

Our Goal For You and Your Car
Our goal is to save you money, not spend it.
This is why each and every car that we service gets a free Courtesy Maintenance Inspection during its first visit.

We aim to let you know about the small problems before they become big.
Right now we have a number of customer cars with well over 200,000 miles, and several approaching 300,000!
And these cars are not just limping along – most look and drive pretty much the way they came out of the showroom.

Proper maintenance is an investment in the life of your vehicle.
Knowing, not just doing, but actually knowing and understanding the difference, makes all the difference.
Be sure your car is properly loved, our professionals will attend to both you and your car’s needs.

Atlantic Motorcar…Extraordinary Service for Extraordinary Cars, just a phone call away, (207) 882-9969!

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