Air Conditioning (A/C) Odor Treatment

1. NOTE: There are typically 4 types of objectionable odors found in a vehicle: Chemical, environmental, human and other interior-generated odors, microbiological odors. Before determining that A/C odor treatment is required, determine the source and the circumstances under which the odor occurs.

   NOTE: Chemical odors are usually constant regardless of the climate control system setting although they may be enhanced by A/C operation. Most chemical odors are caused by fluid leaks or incorrectly cured adhesives. Chemical odors can be eliminated by repairing the leaking component and removing any residue.

   NOTE: Environmental odors usually occur for a short time and diminish after the vehicle passes through the affected area. These odors are typically only detected when the vehicle windows are open, or when the climate control system is operating in a mode that allows for fresh air. Environmental odors cannot be eliminated because they are external in source, but they may be minimized by switching to a climate control setting that uses recirculated air.

   NOTE: Human and other interior-generated odors occur while the source is present and may linger for a short time after. These odors may be more noticeable during A/C operation. Human odors may be eliminated by removing the source and cleaning the affected area.

   NOTE: Microbiological odors, if in the A/C system, usually last for about 30 seconds after the system is turned on. They will be detected while the A/C is turned on and using either outside or recirculated air. Microbiological odors that occur in areas other than the A/C system (for example, water in doors or wet carpeting) may last indefinitely and will be more intense when recirculated air is used. Microbiological odors will not be present at temperatures at or below 10° C (50° F).

1. NOTE: Microbiological odors result from microbial growth supported by warm temperatures and moisture. Microbiological odors are described as musty/mildew type smells and may occur on/in:

   • foam seals
     
   • rubber seals
     
   • adhesives
     
   • standing water
     
   • water soaked carpet/trim
     

1. Eliminate microbiological odors by removing the source and treating the affected area. Allow standing water to drain and dry out. A/C systems may be treated by using A/C Cooling Coil Coating as described in the service procedure.
   

1. NOTE: Identify the type of odor present in the vehicle. Do not proceed with A/C odor treatment if the odor source is found to be outside of the A/C system. Refer to the following list for examples.

   • Transmission Fluid - Oil type or burning smell
     
   • Washer Fluid - Alcohol type smell
     
   • Gear Lube - Garlic/sulfur smell
     
   • Refrigerant Oil - Ether type smell
     
   • Carpet/Trim Adhesives - Fishy, urine or sweet smell
     
   • Evaporator Core Coating - Wet cement type smell
     
   • Industrial Pollutants - Various smells
     
   • Dust - Musty, mildew or wet cement type smell
     
   • Pollen - Sweet smell
     
   • Tobacco - Burning, tar smell
     
   • Body Secretions - Body odor
     
   • Perfuming Agents - Sweet or fragrance smell
     
   • Clothing - Musty, mildew or body odors
     
   • Food/beverage
     
   • Microbiological odors occurring inside of A/C system - Musty, mildew smell lasting about 30 seconds after A/C is turned on
     
   • Microbiological odors occurring outside of A/C System - Musty, mildew smell lasting indefinitely and possibly more pronounced when using recirculated air
     

1. NOTE: Identify the source of the odor.

   • Check the evaporator core drain tube for restriction.
     
   • Check the passenger and driver side carpet for moisture. If moisture is found, A/C odor treatment is not necessary. Diagnose for a water leak as needed.
     
   • Check the blower motor and blower motor cover (if equipped) for moisture resulting from water bypassing the cowl baffling system. If moisture is found, A/C odor treatment is not necessary. Diagnose for a water leak as needed.
     
   • Check the cowl top panel and air inlet screen for standing water or foreign material. If possible, remove any standing water and clean the air inlet screen using a wet/dry vacuum.
     

1. Open all vehicle windows and doors.
   

1. Make sure the A/C is off.
   

1. Select REGISTER mode ( A/C off).
   

1. Adjust the temperature setting to full warm.
   

1. Adjust the blower motor speed to HI.
   

1. Run the engine for 25 minutes to dry out the A/C system.
   

1. Turn the ignition OFF.
   

1. Remove the blower motor.
   

1. NOTE: Blower motor speed controls that are mounted outside of the evaporator core housing and not exposed to the blower motor airflow do not need to be removed.

   Remove the blower motor speed control (if equipped and exposed to the inside of the evaporator core housing).
   

1. NOTICE: To avoid damage to the vehicle interior, do not spill or spray this product on any interior surface.

   Add one full bottle of A/C Cooling Coil Coating to the Flexible Applicator Tool.
   

1. Insert the nozzle into the evaporator housing and direct the spray toward the evaporator core face. Spray the entire evaporator core face until empty.
   

1. Install the blower motor and blower motor speed control.
   

1. Repeat Steps 7 through 11 to cure the evaporator core coating.
   

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