Open the hood of your car by pulling the release lever under the dashboard.Then go to the front of your vehicle and put aside the yellow tab just right above the emblem.Under the hood, you will see the yellow lever you need to press to the passenger side.
Secure the hood open with the hood rod.
Remove the engine cover by pulling the cover-up.
Find the Air Filter box located on the driver's side of the engine compartment.
Loosen all of the four T-25 screws by using a Torx screwdriver. Then remove the top housing of the air filter box by pulling it up.
Remove the old air filter by pulling it out from the air filter box. Clean the air filter box by using a vacuum.
Remove all the dust, dirt, and debris in the air filter box.
Grab the new air filter and put it in the cleaned air filter box by pushing it downward.
Put back the top housing of the air filter box by screwing all four T25 screws using the Torx screwdriver and then put the engine cover back on the engine.
That's it. Replacing the engine air filter on a Mercedes-Benz GLA250 is that simple.