by Frank Walker, V.P. of Marketing, AirSept
Air conditioning odor is often a result of airborne bacteria or fungi that are drawn into the evaporator during normal operation of the a/c system. The fact that evaporator contamination is a by-product of normal a/c system operation makes the odor a rather egalitarian problem. It can occur in any vehicle, regardless of age, brand or of how expensive the model.
Often described as a musty smell like that of dirty socks or rotten egg, a/c odor is immediately noticeable when it occurs. It is however, more than just unpleasant and embarrassing.
Bacteria combine with moisture and contaminants in the evaporator and provide the ideal conditions for mold and mildew formation and growth. People with allergies or respiratory illnesses can experience breathing difficulties or other adverse health effects after enough time in a vehicle in which mold, mildew, and other bacterial or fungal contaminants are circulating in the air.
So all technicians should be prepared to diagnose and repair a/c odor problems.
Step one must be to confirm that the odor is in fact in the a/c system. A moldy smell could come from dampness in the carpet due to a leak from the heater core or other areas of the vehicle. A dead animal smell might actually be from a critter that got into an air passageway and could not get back out. A rotten egg smell could come from food spills gradually aging in the vehicle cabin.
The repair shop that maintains my car got a good laugh when I brought it in with an odor complaint. They found broccoli that I had not noticed had fallen out of a grocery bag and begun decaying — under the driver’s seat.
If it is from the a/c, the odor will occur only when the system is on. Most of the odor-causing microbes in the evaporator will blow into the passenger compartment and quickly dissipate after the first ten minutes of operation.
If the odor is present in the vehicle even when the a/c system is off, or remains long after the first few minutes of operation, look for sources other than the evaporator.
Step two is to kill the bacteria and fungi in the evaporator that cause the odor. You’ll need to use antimicrobial technologies that kill bacteria and fungi rather than just mask the odor.
Otherwise, bacteria and fungi will continue reproducing and growing. That new microbial growth will produce a musty odor that will quickly overwhelm any perfume, scented oil, or other cover-up fragrance used.
Bacteria can grow on any surface, including metal, plastic, or foam. A small amount of bacterial or fungal growth in a nook or cranny in the a/c system can cause a noticeable odor.
Choose an application method that injects or infuses the antimicrobial into the air conditioning system and spreads it throughout the evaporator.
Step three is to think long term. What does your customer expect about how long the service you provided will last?
Aftermarket a/c odor treatment products are available that leave a coating in the evaporator that helps prevent odor recurrence for up to one year. OE versions feature a similar coating technology that protects against odor return for up to three years.
Antimicrobial formulations that do not include a residual coating wash out of the evaporator with the condensation that is a normal by-product of a/c system operation. Once the antimicrobial is flushed out, airborne bacteria can quickly re-colonize the evaporator and cause odor to return.
Once you understand that air conditioning odor is the result of microbial growth in the evaporator, you can explain the treatment options to your customers, and the solution is as easy as one, two, three.
Information provided by Frank Walker, V.P. of Marketing, AirSept, Inc. AirSept is a Tier 1 or Tier 2 supplier to sixteen OE vehicle manufacturers globally. The Atlanta-based supplier provides air conditioning filtration systems, a/c odor treatment, cooling, transmission, and other automotive repair tools and products to OEMs and to the aftermarket. www.airsept.com