Cabin filter: when to change and what happens if you don’t
The cabin filter directly affects what you breathe, how quickly windows defog, and how well your HVAC system moves air. When the filter is clogged, airflow drops, windows fog more easily, and you may get a stale/musty smell.
Signs your cabin filter is clogged
- Weak airflow even on higher fan speeds
- Windows fog up easier and take longer to clear
- Bad smell, especially in damp weather
- More dust / allergy symptoms inside the cabin
Simple test: set the fan to max. If it used to blow hard and now feels weak,
and the fan itself sounds normal — the filter is often the reason.
When to change
- Minimum: once a year (before the wet autumn/winter season is a great time)
- City + dust + pollen: consider twice a year
- Gravel roads / dusty environments: it clogs faster
Which filter to choose
- Standard: fine for basic dust filtering.
- Activated carbon: better for odors and exhaust fumes (recommended for city driving).
- Don’t buy the cheapest “paper” filter — it can deform and let dirt through.
Don’t confuse it with other issues
- A sweet smell + fogging + greasy film can indicate a coolant leak (heater core).
- Squealing/whining noises can be the blower motor, not the filter.
Log cabin filter changes (date + mileage)
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