The Chevy HHR 2.2 LT Ecotec motor is equipped with a plastic upper intake that also serves as a cosmetic engine cover. On the back of this intake/cover is the air filter location. From this point on, I will refer to this whole setup as the "unit".

The entire unit is held in place by 1 single torx bolt and 2 protruding snap prongs. While facing the motor, grab the unit on the backside near the firewall and pull up. You should hear a pop an the unit will be released from the snap prongs on the backside.

The single torx bolt is located on the front left side of the unit near the coolant tank fill spout. There is not a huge area of movement in this area so the method I found to best loosen the torx bolt was to take my T-25 torx bit, and use a 1/4" socket/socket wrench. The torx bolt DOES NOT fully come out as it is held in with a gasket. Keep lifting up on the unit until you see that the torx bolt is no longer threaded.

At this point, the unit is still hooked up to the air intake hose, throttle body, and mass airflow sensor (MAS). Using the flathead screwdriver, loosen the hose clamp on the left side of the unit to remove the air intake hose (made from hard fabric).

Next, loosen the throttle body hose clamp located on the hose on the front of the unit.

Right above the throttle body hose, unclip the MAS pigtail wire. The entire unit is now completely unhooked and can be lifted out from the vehicle.

Flipping the unit over, you will find 7 torx bolts that holds on a cover that houses the air filter. Using your T-25 torx bit, loosen all 7 bolts. They are designed to not fully come out of their plastic housing.

Once all 7 bolts are loose, you can remove the filter cover exposing the air filter.

Remove the dirty air filter and discard. Clean any built up dirt that may have accumulated around the unit and filter housing.

With the unit clean, place the new air filter into the unit. The filter can only go in one way due to how the filter gasket seats into the unit.

Place the air filter cover back and retighten all 7 torx bolts.

Flipping the unit back over, attach the air intake hose back on and tighten the hose clamp.

Snap the mass airflow sensor pigtail back in.

Attach the throttle body hose back on and tighten the hose clamp.

Align the single front torx bolt on the unit and retighten.

Align the unit back over the snap prongs on the backside and give the unit a firm push to reseat it back on the prongs. Note that you may have to grab the oil filler neck and guide it back into place in order for the unit to align and seat properly.

Clean up, you're done!