Do it yourself, change the air filter on your Subaru Legacy, made between the years 2003 and 2009. This replacement is very simple and you can do it in the back of your garage in under 10 minutes. You will need a new air filter and a flat blade screwdriver.
Open the hood of your car and locate the air intake hose and the oxygen sensor. They should look like in the picture below. Remove the sensor by pressing its securing tab with your fingers or using the flat blade screwdriver. Then, release the metal collar indicated below by unscrewing its bolt.
After you finish these tasks, go to the air filter box, which is slightly to the left and disconnect the two clamps that secure it, shown in the image below. This plastic box is the compartment where the air filter is located.
After you remove them, you will be able to lift up one half of the air box, giving you access to the air filter, as shown next.
At this time you can replace the old filter. Always compare the old filter with the new one, just to be sure. Now, in order to finish the replacement process, reverse the steps presented above. Install the filter properly, seal the air box with the two clamps, reinstall the air intake hose and its collar and plug back the oxygen sensor, at the end. This is all you need to know, in order to change the air filter on your Subaru Legacy manufactured between the years 2003 and 2009.