All Wheel Drive Auto: Independent Seattle Subaru Service


Subaru AC Maintenance Service

Understanding the importance of periodic maintenance for your Subaru’s Ac or also known as Climate Control System can go along way in preventing expensive repairs as well as ensuring the Ac works during the summer and the defrost works during the winter.

The first thing to really understand is AC (Air Conditioning) is not really making something cold, it’s really creating pressure and heat and then drastically dropping the pressure, which in turn lowers the temperature which creates a cooling effect.  In order to do this there must be a charge of gas in the system that the Air Conditioning compressor can compress which is how heat is created. An AC system with a low charge of gas also known as refrigerant will not create as much heat as the pressures will be lower, thus the final temperature will not be as cool as needed to properly cool the cabin area in your Subaru.  

Conversely the opposite is true during the winter, if the Ac system has a low charge the defrost will not be able to remove the moisture from the windshield as efficiently as it should.  Why is this? When you select defrost or defrost & floor settings the AC compressor is also turned on to speed up the process of removing moisture or defrosting the cabin.

Why would the system become low?  

Unlike a freezer or refrigerator your Subaru is a small earthquake driving down the road. It’s far from stationary, and while engineers take this into consideration when designing the car, the issue is at it ages, as rubber o-rings and rubber hoses deteriorate with age they do not hold pressure as well, this is especially true anywhere rubber hoses meet hard lines.  There are other places that can develop leaks, this includes the evaporator core, condenser, AC compressor, expansion valve and more.

The proper way to leak test a system is to fill it back to capacity prior to leak testing, a small leak will reveal itself in a more pronounced way under full pressure, rather than low pressure.  Think of it kind of like a slow leak in a tire, what happens is when the tire is inflated fully, it leaks out a small amount of air. Sometimes the atmospheric pressure and the small leak in a tire equalize somewhat to slow the leak down, the same thing happens in your AC system. This can create a situation where the system will leak out some of the gas but not all of it.

There Is a lot more to an Ac system than just gas and leaks!

Modern Subaru vehicles have an abundance of electronic controlling the AC system. A failure in any of the many circuits that enable proper AC function can also not allow the system to perform properly.  This can be as simple as a faulty relay or as complicated as a problem in the can bus system. If you have an AC system that doesn’t function properly it may not just be a low charge, a diagnosis is always the best place to start, with all of the new controls, like dual zone climate control you might as the driver experience warmer than desired air on your side but the passenger side might be 34 degrees, expecting a recharge to resolve that just isn’t going to happen.  Since 2005 most Subaru vehicles also utilize a climate or cabin filter to filter out contaminants coming into the cabin area.

Subaru Cabin Filter New VS Old

If the filter is restricted, air flow into the cabin will be reduced which can greatly affect the ability of the climate control systems to function properly, not to mention this has become a great place for mold and bacteria to grow if the filter isn’t replaced based on the area you reside in and how you use your Subaru. The absolute best thing you can do to maintain your Subaru’s AC system is to replace the cabin filter most likely on a yearly basis for most drivers, check the outlet temperature of the vents with the AC on max periodically and have it serviced on average every 2 years after the first 5 years of ownership has occurred.  

If your local to us here is a Subaru Service Coupon that can help you save on Ac service .

Thanks for Reading

-Justin Stobb

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