Is Your Vehicle's Air Conditioning Blowing Hot?

Quick facts

  • Low refrigerant always indicates a leak. Refrigerant does not deplete in a sealed system.
  • A starved A/C compressor can fail entirely when refrigerant carries insufficient oil through the system.
  • Annual A/C inspection can catch small leaks before they cause compressor damage.
  • Shops must be certified to handle refrigerant under federal environmental regulations.

Do you think that it is time to add refrigerant to the A/C system in your vehicle? There was a time that if you turned on the A/C in the spring and the air temperature seemed warm, you would merely bring your vehicle into a repair shop and they would add some refrigerant. It was even considered normal for an air conditioning system to lose up to a pound of refrigerant each year.

The thinking on refrigerant loss has changed drastically since that time. Scientists have concluded that A/C refrigerant like R-12 and R134A are partially responsible for the depletion of the earth's ozone layer. So in the mid-'90s car manufacturers were required to make their A/C systems more leak-resistant by using improved materials for lines, hoses, and seals. Federal and state regulations also require that repair shops have the correct equipment and training for handling refrigerant, so that an A/C system that is leaking does not continue to be filled and pollute the environment.

To take care of the air conditioning system in your vehicle we recommend an annual inspection which would include:

  • Inspect, adjust and/or replace A/C belt as needed
  • Clean radiator and condenser fins
  • Ensure the evaporator drain hose is open
  • Check that all system electrical connections are secure
  • Make sure vacuum control lines are connected properly and in good condition
  • Check duct outlet temperature
  • Check that all compressor hardware is intact and secure
  • Check the condition of all the lines and connections and make sure that they are tight
  • Test system pressures to make sure they meet specifications
  • Test low-pressure cut-out switch
  • Check for leaks after any A/C service is performed

If the vehicle is low on refrigerant it can cause major damage to the A/C system. The system relies on the refrigerant being at a sufficient charge to carry oil through the system and keep it lubricated. If the compressor starves for oil it can cause a failure. Some warning signs are:

  • Insufficient cooling from the vents
  • Unusual odors from the vents
  • Noisy belt, compressor or blower motor
  • A rhythmic clicking noise under the hood with the A/C or defroster on
  • An electric cooling fan that cycles on and off quickly
  • A window that won't defog when using the defroster
  • Water on the floor of the passenger compartment

Regular inspections can help catch a problem when it is still small, before it causes major damage to the A/C system. It is also a protection for our environment to keep an eye on our A/C system, so we don't lose all the refrigerant to the atmosphere. Have it checked out regularly and if you experience any of the warning signs, have a qualified shop with technicians certified to handle refrigerant diagnose and repair it.

Frequently asked questions

Common questions

Why does the A/C compressor need oil, and how does refrigerant deliver it?

The A/C compressor is a mechanical pump with moving parts that require lubrication. Rather than having its own separate oil reservoir, the compressor relies on oil that is dissolved in the refrigerant and circulates with it through the system. When the refrigerant level is low, less oil circulates, and the compressor runs partially or completely starved. Extended operation in this state causes internal wear and eventually seizes the compressor.

What does the rhythmic clicking sound under the hood mean when the A/C is on?

A rhythmic clicking or cycling that is faster than normal usually means the compressor clutch is engaging and disengaging rapidly because system pressure is too low. The low-pressure safety switch cuts the compressor off to protect it, but as pressure briefly recovers, it kicks on again. This cycle repeats rapidly and is a clear sign that refrigerant level is low and the system has a leak.

Why would there be water on the passenger floor when the A/C runs?

The evaporator core chills the air inside the cabin, which causes moisture from the air to condense on it, the same way a cold glass sweats on a hot day. That condensate is supposed to drain through a tube that exits through the firewall and drips onto the ground. If the drain tube is clogged, condensate backs up into the HVAC box and eventually finds its way onto the floor, often soaking the carpet and causing mold. Clearing the drain tube is a simple fix.

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All About Automotive — 1850 NW Burnside Rd, Gresham, OR · (503) 465-2926

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