Musty Odor After Rain in BMW 3 Series
A musty smell after rain typically indicates moisture accumulation in the cabin, often due to clogged evaporator drain, wet cabin air filter, or water intrusion from sunroof drains or door seals.
Diagnosis Details
Possible Causes
Clogged A/C evaporator drain tube causing water to pool and grow mold/mildew
Wet or contaminated cabin air filter (microfilter) from moisture ingress
Blocked sunroof drain tubes leading to water seepage into headliner or footwells
Faulty door or window seals allowing rainwater entry
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What You Should Do
Inspect and clean the A/C evaporator drain tube; check and replace cabin air filter if damp; clear sunroof drain lines; examine door and window seals for leaks; dry out any wet carpet or padding to prevent mold growth.
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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.