Cabin Air Filter – Dave’s Garage

Most cars sold today have a cabin air filter, usually located behind the glovebox in the dashboard. This will filter dust, pollen and dirt entering the Heating, Air Conditioning and Ventilation System.

cabin air filterI recently noticed the airflow on my Subaru’s heater was weak on one of the many below zero mornings. I remembered this car had a cabin air filter, and I know I have never replaced it. The owners manual states the filter should be replaced annually, or every 15 thousand miles, depending on the conditions the car is driven in. This car has 230,000 miles on it, and this was the factory cabin filter, I had never changed it. I live on a very dusty dirt road, so I should theoretically be changing the filter more often.

The filter was inexpensive enough, and in stock at my local friendly auto parts store. When I took the old filter out, I was not surprised to find the filter was quite dirty. I was surprised to find a great deal of dirt and pine needles sandwiched between the A/C evaporator and the filter. I pulled out about a cup of dirt, and a handful of pine needles.

I used a vacuum cleaner to vacuum out the HVAC box, and a paint brush to get all the dirt off the A/C evaporator. I turned the heater fan on high to blow out any remaining dust, dirt and debris.

I was very impressed with the improvement in the airflow with the new filter. The volume of air going through the cars vents was noticeably higher.

The heater works much better now.

Cabin air filters in cars are a relatively new phenomenon. As cars have become more and more maintenance free, it is a bit unusual to have something new to remember to maintain. If the new filter does not include a sticker to log the date and the mileage of the replacement, it is a good idea to log this information on a piece of masking tape and place it somewhere on the car as a maintenance reminder.


Please email all inquiries to: Dave
or snail mail
32 Turkey Hill Road
Richmond VT 05477

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