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

Condition:
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. 

Correction:
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.

Correction:
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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