AC Refrigerant System Service (Gas & Diesel)

AC Refrigerant System Service (Gas & Diesel)

Summer’s arrival means your vehicle’s air conditioning system is going to be under a serious strain. If you have not had your A/C system serviced in a while, now’s the time. While most newer vehicles may simply be able to get away with having their A/C recharged, older cars and trucks may require a little extra attention.

There are several main types of automotive air conditioning systems: the orifice tube and expansion valve are the most common, or you can find combinations of the two. In any case, to understand how a car’s A/C works, you need to know each of the components and how they contribute to that operation. Those primary components are the compressor, condenser, evaporator, accumulator (or receiver-drier) and orifice tube (or expansion valve).

Here is an overview of what you should know about air conditioning operation and how each of these components contribute to the cooling of your vehicle cabin.

How does a car’s AC work?

Here is a quick rundown of how each part of a car’s AC contributes to air conditioning operation:

  • Refrigerant: The air conditioning system gets filled with refrigerant gas known as Freon or R134A or R12334YF. Refrigerant can change its physical properties during compression, which, as you’ll see momentarily, is crucial to the operation of an air conditioning system.
  • Compressor: The refrigerant gets turned into liquid by the compressor, which, as the name suggests, compresses that refrigerant. As the gas gets compressed, it heats up, at which point it gets sent to the condenser.
  • Condenser: The condenser is where the refrigerant gets cooled. This component features a section of coils that air from outside passes over, removing the heat from the compressed gas. This results in the gas cooling and condensing into a liquid state.
  • Accumulator: The accumulator (also referred to as a receiver-drier) is a canister in the air conditioning system that features a desiccant to absorb moisture. This part may have a sight glass on the top of it, allowing you to observe flow. This is the part that results in the air entering your vehicle having low humidity levels.
  • Filter: Part of conditioning the air involves cleaning it. The air conditioner’s inline filter will remove any debris in the air, trapping it and allowing the clean air to continue passing through.
  • Expansion valve: This part restricts the flow of refrigerant, causing it to change from a liquid at high pressure into a low-pressure mist before it goes into the evaporator.
  • Orifice tube: An orifice tube is an alternative to an expansion valve that essentially creates the same refrigerant mist result.
  • Evaporator: When the mist flows through the evaporator, a blower motor will push the air over the evaporator’s cold tubes to create cool air that then gets sent into the passenger compartment of your vehicle.


What is included in an AC Refrigerant System Service?

Once you take your car in, technicians will measure the amount of pressure in your system, and if it is low, they will recharge the system to get within manufacturer’s specifications. They will then run your car for a few minutes with the A/C on high and use a special thermometer to measure the system’s output. If it is not within the necessary parameters, you may have a leak somewhere in your system.

Fixing a leak is trickier than you may think. Your technician will hook your vehicle up to a special refrigerant recovery system and drain any of the harmful gas from your car. At this point, the technician will inspect all your air conditioning hard lines to make sure there are no obvious cracks. They may add a tracer dye to the system to help. The bad news is that leaks are sometimes hard to find, and tracer dye is not necessarily a cure-all. The good news is, your expensive hard lines are usually made of aluminum and rarely fail. Instead, it is likely one of your system’s components is the culprit. First up is your compressor.

The best way to keep your compressor from failing is to have your A/C system serviced once a year, including the addition of the right kind of lubrication for your unit. If it does come down to replacing your compressor, most responsible shops will recommend going ahead and swapping out several periphery components at the same time. Why? The easy answer is working on an air conditioning system is about as much fun as sticking your hand in a blender. Twice. So to avoid draining your refrigerant, removing your compressor, installing a new unit and refilling the system with new cool stuff, only to have you come back in a week and say it’s still not cold enough, it makes sense to replace the necessary components. It keeps you from having to waste time and money, and it makes sure they get the problem solved the first time.


How do you tell if you need an AC Refrigerant System Service?

  • No air: If you get into your car and turn the air conditioner on full blast but get nothing, that is a problem. This issue can be caused by a few things: a blown fuse, failed blower motor or blower resistor, or blocked cabin filter. 
  • Strange Noises: Any kind of noise that was not there before is alarming. Most common A/C noises are rattling, banging, or humming. This issue could indicate: an obstruction such as leaves or other debris in the system, worn bearing, failed compressor clutch, blower motor, or major component failure. 
  • Foul Odors: When you turn on your air conditioning, you should not smell anything. Foul odors indicate the growth of bacteria such as mold, mildew, fungus, and other microorganisms behind the dashboard on the evaporator. The foul odors are often caused due to: age of the vehicle, cabin filter,  infrequent use of the air conditioner, or moisture in the system due to excess condensation. 
  • Damp Floor: Moisture that is supposed to be directed outside of your vehicle gets backed up and starts to spill out onto the passenger’s side floor. This is often the result of: clogged drain lines or excess condensation. 
  • Balmy Air: When the air is cool but could be a lot colder and struggles to reach a comfortable temperature, this can be caused by: low refrigerant, obstructed condenser or failed condenser, or obstruction in the system affecting the pressures. 
  • Unexpected Changes in Temperature: If the air was set to a cold temperature and was working sufficiently, but suddenly turns warm, it could be caused by: failed expansion valve, clogged evaporator, or low refrigerant causing a lack of pressure. 


Have your AC Repairs done by the experts at AG Automotive!

Air conditioning troubles can be a real headache. You can help to prevent any major air conditioning troubles by being proactive in having your air conditioning system serviced. How often is it recommended to service your car’s A/C? Annual service in the springtime is the best time to bring your car in for an ac refrigerant system 

At AG Automotive, we see our share of vehicles with air conditioning troubles. From trucks low on refrigerant to car A/C compressor issues, we are prepared to help! Our ASE Certified Technicians are knowledgeable and have the expertise to diagnose and repair any A/C issues your vehicle may be experiencing. 

While you can technically recharge your vehicle’s refrigerant yourself, it is best left to a qualified professional if you are not confident in vehicle maintenance. All refrigerants tend to displace oxygen, which means if you accidentally evacuate the system, the stuff could literally push the air out of your lungs.

Don’t Second-Guess the Condition of Your Vehicle

Many auto owners struggle to know if the right work was done the right way on their car. As a courtesy, we provide digital vehicle inspections and photos so you can quickly and easily see what our experienced, professional technicians are seeing. Overall, we go the extra mile to help you make informed decisions on the repair and maintenance plan of your vehicle, so you can drive with confidence every time you get behind the wheel.