All Wheel Drive Auto: Independent Seattle Subaru Service


Subaru Cabin Filters & Winter

Did you know that your when you turn on the defrost
it uses the A/C system?

Subaru Cabin Filter

Have you noticed your windows fogging up or not clearing very well?

Do you smell an odor when you first turn on your defrost or A/C?

Mold and mildew can develop in your Subaru’s air conditioner and heater system.  The odor is most likely a build up of bacteria and debris that is deep inside the vents. The growth of bacteria is often behind the dash panel on the evaporator. This smell may be harmful and not healthy to breathe, especially if you have respiratory problems. Depending on the climate where you live this can become a larger problem in the winter.  If you are in Montana or Wyoming the winter months are dryer, but here in the Pacific NW it’s just plain wet, as in we live underwater this time of the year. Keep in mind in some cases unless you put the cabin filter under a microscope, (which we are not going to do here), you may not see whats hurting you.

Also your air filter and cabin filter needs to be checked as they can collect dirt, condensation, dust mites and other harmful pollutants through out the entire year.

To avoid any problems with your Subaru’s air conditioner and defrost system, have All Wheel Drive Auto perform a service check at your next service, or if you are not local to us make sure who ever is servicing your later model Subaru goes through this process for you.

This includes and inspection of the cabin filter and vents. It is also a good idea, after the Spring siege of pollen and plants in bloom to have your cabin filter checked then as well.

Cars equipped with cabin filters and either poorly performing Ac systems and or non functioning Ac systems can be more likely to grow mold than vehicles with proper functioning equipment in some climates as well.  Almost no one thinks of checking the Ac system in the winter but the job of the Ac compressor is to help dry moisture off of the windows in the winter time. If the air being pulled into the cabin area is full of moisture, and the system can’t help dry out that air, its just going to stay that way.  If your Ac system didn’t work in the Summer, its still not going to work in the winter and might not be a bad idea to service it.

Lastly don’t forget to clean the inside of your window, the air you breathe in, comes out as carbon dioxide and leaves a film on the inside of your windshield, in the winter months this can affect cold window visibility more so than in the Summer time.

Thanks for Reading

-Justin Stobb

Helping you with your Subaru!


3 Responses

  1. Justin, My name is Don Bauml and I live in Warsaw, MO. I have a 2006 Subaru B9 Tribeca. The original engine had a blown headgasket. and a leaking timing cover. I had a used JDM Subaru engine and transmission installed. I had to get the trans programmed at the Subaru dealership in Lees Summit, MO because it was shifting roughly. Fine now. After reading your very informative web page I have a question. I have been doing 5k mi oil changes with Mobil 1. After reading your statements I intend to switch to 3k mi oil changes. Should I stay with Mobil 1?, or what oil would you recommend for this year car and engine. Thank you for taking the time to read this and reply.


    1. Hello Don,

      I am not all that familiar with where you live, but in searching in seems it’s a pretty mild climate which is a little gentler on engine oil. On that era Tribeca I would use synthetic “blend” and change it every 3000 miles. I like the GTX or high mileage oil for that application. All of that is really based on the climate here and what we know to work for our local customers.

      What I would also say is that I have no problems with Mobil 1, but we have observed higher than average rates of oil consumption in Subaru vehicles, mostly turbos, but even on some N/A engines. If you are not experiencing use issues, there may be no real benefit to changing brands.

      What I would really suggest is sticking with the oil you are already using, but really giving it some scrutiny at 3000 miles for breakdown and oil usage.

      Hope that helps


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