Mazda Tech Tip: Air Conditioning Musty / Mildew Odor

Mazda Tech Tip: Air Conditioning Musty / Mildew Odor

A musty odor may come from the vents when the A/C system is operating. It is most noticeable when the A/C is first turned on.
  • Models:
  • 1998 MPV
  • 2002-2003 Protege5
  • 2013-2019 CX-5
  • 2006-2015 Mazda5
  • 2000-2006 MPV
  • 1999-2005 Miata
  • 2007-2012 CX-7
  • 2003-2019 Mazda6
  • 1998-2002 626
  • 1998-2002 Millenia
  • 2007-2019 CX-9
  • 2011-2014 Mazda2
  • 1998-2003 Protege
  • 2006-2019 MX-5
  • 2004-2019 Mazda3
  • 2016-2019 CX-3

A musty odor may come from the vents when the A/C system is operating. It is most noticeable when the A/C is first turned on. This odor is the result of mold growth in the A/C evaporator and case which is caused by condensation, dust, and pollen within the cooling unit. This condition is usually worse during high humidity conditions. 

Mazda Air Cooling Coil Coating is available to encapsulate the mold to reduce odors. If the product is properly applied, it can effectively reduce the musty/mildew odor for up to three years. This treatment provides a durable coating that will aid to prevent biological reactions that lead to odor concerns. 

It is applied to the evaporator in a misted form that is introduced by way of either the cabin air filter, re-circulate door, the blower motor resistor access or the blower motor air intake. TSB NUMBER: 07-002/19 contains the specific instructions for each vehicle. Proper application requires the evaporator surface to be present.

Clean the throttle valve and chamber of the electronic throttle actuator. Nissan recommends the use of a non-chlorinated carburetor cleaner.

Courtesy of Brake & Front End.

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