All Wheel Drive Auto: Independent Seattle Subaru Service


Some Subaru Fuel Economy Tips


Whenever gas prices rise there is this instinct we seem to have to get mad.  Corporations only react to the market place if we dont buy what they offer us, they will offer better choices, if we trade in a 5 year old car for a new one that only gets marginally better fuel economy that wont create real change, I over the last few years have really been trying to drive this point home.  We really speak with our actions and thats the only thing auto makers will adjust to.   Subaru wont bring in the U.S. Diesel until there is a real proven market for it, but they have finally broken into the 30mpg range with an AWD vehicle.

The 2012 Impreza, due to some significant technology improvements mostly with the transmission is stated to be in the mid 30’s in terms of miles per gallon, I say that’s great for an All Wheel Drive vehicle, but if you have no plans in the near future to purchase one this Summer I thought I would repost some fuel economy tips from an older article I wrote in 2007.  These are suggestions for actions you can take

that will make miles per tank improvements, or prevent a drastic decrease in fuel economy.

So if you have owned your Subaru through any winter driving season, you have come to appreciate how well the all wheel drive functions when the road conditions are at their worst.  One of the draw backs to all wheel drive is the potential for reduced fuel economy so it is especially important to keep your Subaru’s systems in tip top shape.  Also remember any increase in fuel economy comes with the added bonus of decreasing the volume of tail pipe emissions produced.  It’s a win win situation, save some money and lesson your cars impact on the environment. Below you will find some tips and information on how to get the most out of every gallon of gas.

  1. Check your tire pressure every month, a low tire can increase rolling resistance which equals a decrease in fuel economy. Adding to that an improperly inflated tire can potentially affect the vehicle stability as well.
  2. Maintain your vehicles alignment, a vehicle that doesn’t track straight will increase fuel consumption as the car fights through resistance to track straight, you will have the added bonus of protecting your tire investment with yearly alignments, or anytime you have had a mishap including hitting a curb or large pothole.  If you live in Washington state you could feasibly need to align your car after every drive due to the condition of our roads.

3. Change the fluids in your vehicle at normal service intervals. Old fluids can increase drag. Another words it takes more horse power and fuel to spin through old motor oil in the engine, old gear oil in the differentials and transmission as well. Another added benefit of changing fluids on your vehicle is decreasing the possibility of component failure from inadequate lubrication.

4. Try to use the defrost function less in winter, and the air conditioning less in the summer.  Whenever you use the defrost the air conditioning compressor cycles on to help hydrate moisture off the windshield.(assuming your vehicle is equipped with air conditioning) now while this is a great feature, it is also large drag on the engine and will decrease fuel economy.  Consider using an anti fogging agent on the windshield to help decrease the amount of time you need to have the defrost on.  Keeping your air conditioning system in good shape is also a good idea to decrease the amount of ac compressor cycles thus decreasing the amount of drag on the engine.

5. Keep your Subaru properly tuned and serviced, and don’t ignore check engine lights or drivability symptoms. Worn spark plugs and dirty filters can contribute to a decrease in engine performance and fuel economy.  If your check engine light is on your car is trying to tell you that the computer has recognized a problem.  If your Subaru is running roughly you are definitely cheating yourself at the pump.

6. Driving habits, yes the way you drive has a large affect on the overall fuel consumption of your vehicle.  Speeds under 65mph will yield better fuel economy than speeds over 65mph,shutting the vehicle off during extended periods of idling is also a great way to conserve fuel.

7. Clean out the garage and make room for your Suby. If you have a garage and it’s too full of stuff to park your car in, consider some organizing.  Parking your car in the garage during the winter will decrease the amount of time that the vehicle has to run prior to performing at its optimum, which will greatly increase fuel economy and reduce the volume of emissions coming out of the tail pipe.  Your vehicle has to reach a certain temperature in order to go into what is called closed loop, this is when the vehicles computer uses many points of live data to determine the proper amount of fuel needed to achieve the most power, performance and the best economy.  The higher the starting temperature of the engine, the quicker it can go into closed loop.  While this tip is more about your garage than it is car maintenance, its purpose is to be food for thought and a good excuse to organize your garage.

8. Try to be proactive about your car and its maintenance needs, not reactive. Remember each of us doing something, is much better than none of us doing anything.

Thanks for reading


4 Responses

  1. Why does Subaru specify tire pressures of 30 rear / 32 front for my Forester and not an even pressure when it seems tire size and all things being equal is important for the all wheel drive. I’ve checked the service w/o and the Subaru dealer sets them all at 32.

    1. Hello Dale,

      Front end weight, however setting them to 32-34 lbs will really have no ill effects. It’s not uncommon in increase tire pressure based on load, and it’s not a bad idea if you load the rear of your Subaru to also increase the tire pressure to help stability.

      Hope that helps


  2. Every time I start reading your website… I need to remember to pack a lunch !! There is so much good info here.

    So I have noticed the difference in fuel economy when the AC is used. I’ve tried to not use it as much as possible, but at this time of year, the windshield defrost needs to be used even at least as a partial blend and like you’ve stated, this defrost use activates the AC system.

    Any thoughts on pulling a fuse or installing a switch on the compressor’s electric clutch circuit?

    1. Hey Dale,

      Not a great idea as the ECM controls the AC compressor.

      Thanks for the feedback on the Site!


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