Musty Smell from AC in 2019 Honda Civic
A musty odor when the AC is running typically indicates moisture buildup in the evaporator core or cabin air filter, leading to mold or mildew growth. This is common in humid climates and is not an immediate safety risk, but can affect air quality.
Diagnosis Details
Possible Causes
Clogged or dirty cabin air filter trapping moisture and debris
Mold or mildew on the AC evaporator core due to condensation not draining properly
Blocked evaporator drain tube causing water accumulation
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What You Should Do
Replace the cabin air filter first.
If odor persists, use an AC evaporator cleaner spray (follow product instructions).
Check the evaporator drain tube for clogs and clear if needed.
Run the fan on high with heat for 10 minutes to dry the system after cleaning.
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Disclaimer: This AI-generated diagnosis is for informational reference only. Always consult a qualified mechanic for an in-person inspection. AutOwner is not responsible for decisions made based on this information.
