Something feel not-quite-right with your car’s A/C system? Here’s what’s going on, and how to fix it

Quick notes:

– Usually, common warning signs will alert a driver when the A/C starts to fail

– A/C systems can quickly become breeding grounds for mold, mildew or fungus

– Recharging the unit can be done at home

A car’s air conditioning unit compressor is the most important component of a vehicle’s air conditioning system. The unit starts to wear and tear every time the A/C is turned on. Pressurized units must be completely sealed to function properly. Once the pressurized systems develop any sort of leak, the unit will no longer be able to produce cold air.

Usually, common warning signs will alert a driver when the A/C starts to fail.

Seven signs your A/C needs servicing

  1. No airflow. No air coming from the vents is a common problem in unit failure. The cause could be a blower motor, switch, or multiple other system issues.
  2. Warmer temperatures. A typical warning that the compressor may be going out is the A/C will no longer blow out cold air. Air seems to be running, but the system is blowing warm air because refrigerant is not running through the system.
  3. Water on the floor. Air conditioners generate water when it’s running. When working correctly, this excess water exits via a pipe outside the car. However, when the A/C is broken, water will collect inside the car instead. The leakage will cause the carpet to become wet. If not fixed, the moisture will destroy the carpeting, cause odor, and possibly damage the vehicle electronics.
  4. Loud noises when the compressor is running. The compressor relies on various components and uses a sealed bearing to turn. If this bearing is damaged, then it will make it difficult for the A/C’s compressor to function.  If any of the interior components fail, then all sorts of noises can be produced as a result. A leaking or worn out bearing will produce a high pitched squealing or grinding sound, while a seizing or seized bearing will produce a grinding noise or a noticeable belt squeal.
  5. The compressor clutch is not moving. The A/C compressor has a clutch that is connected to the engine via a pulley. This allows the A/C compressor to use the engine for its source of power. If the clutch becomes stuck or breaks, then it becomes unable to transfer this power from the engine to the compressor. Sometimes the clutch itself can be replaced. Usually replacing the entire compressor turns out to be the most efficient repair.
  6. Foul odor. UnfortunatelyA/C systems can quickly become breeding grounds for mold, mildew or fungus as the car becomes older. Turning on the car’s air conditioner to a maximum often cause bacteria growth due to the excess water that is dripping in the unit. Microbes could be the cause if turning on the vehicle’s A/C system generates unpleasant odors along with cold air.
  7. Leaking Fluid. The A/C compressor has internal bearings that prevent fluid from leaking while it is pressurizing the refrigerant. Fluid can easily leak when the bearings become worn or damaged.
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Recharging your vehicle’s A/C

When a car’s A/C stops blowing cool air, adding more refrigerant can be a quick fix. However, recharging the AC is only a temporary fix. If the system is missing refrigerant, then it means the air conditioning system has a leak and must be repaired by a mechanic. Since refrigerant does not evaporate in an airtight system, air must be leaking in. Recharging the unit can be done at home with an AC recharging kit.  This is an efficient task to perform to regain cooler air temporarily. However, this method can cause more problems with the system if it is done incorrectly.

  1. Turn on your AC. Start your car and turn on your AC, as high as it will go.
  2. Determine the ambient air temperature.  Autozone warns customers to charge the vehicle if the temperature of the air is 55 degrees or below. Your recharging kit should contain a recharging hose that has a pressure gauge. The packaging for the refrigerant should provide guidelines so you know what pressure to charge the system to, depending on the ambient air temperature readings.
  3. Locate the low-side service port. The service port is typically found on the line connecting the accumulator and compressor. Your car’s service manual should let you know exactly where this port is located on your vehicle.
  4. Attach the charging hose. Before attaching the hose, wipe away any dust with a clean rag. Once it’s clean, attach the charging hose to the low-side service port until the connection is secured. It could be in the wrong port if the hose does not attach easily.
  5. Add refrigerant. Follow the refrigerant instructions and add the refrigerant to the system.
  6. Charge system. After determining which pressure to use, according to the provided ambient temperature guidelines, constantly monitor the pressure readings while charing your A/C system. The pressure gauge and the guidelines will help you make sure you don’t overcharge the system.
  7. Return to the inside of the car and check the temperature. After the A/C system is charged to the provided pressure, remove the hose from the port. Insert a thermometer into one of your car’s vents on the driver’s side and check the temperature. If charged properly, your system will blow cold air. Problem solved!

If the car’s system show signs of a recharge, first have the A/C system inspected to ensure that the A/C recharge addresses the problem properly.

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