BMW 3 Series AC Not Cold with Musty Smell
The AC system is blowing warm air and emitting a musty odor, indicating a likely issue with the evaporator core or cabin air filter. The musty smell suggests mold or mildew buildup, while insufficient cooling points to a refrigerant leak or compressor problem.
Diagnosis Details
Possible Causes
Clogged or dirty cabin air filter causing restricted airflow and musty odors.
Mold or mildew on the evaporator core due to moisture accumulation, leading to bad smell and reduced cooling.
Low refrigerant level from a slow leak, reducing cooling performance.
Faulty AC compressor or expansion valve causing inadequate cooling.
Related OBD-II Codes
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What You Should Do
Start by replacing the cabin air filter and cleaning the evaporator drain tube.
If the musty smell persists, have the evaporator core professionally cleaned or replaced.
For the cooling issue, check refrigerant pressure and inspect for leaks; recharge if low.
If the compressor is faulty, it may need replacement.
Related Repairs
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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.
