Air Filter Housing and Air Flow Sensor - Removal and Installation

Tools

• Medium flat-tip screwdriver
• 10 mm socket and ratchet
• 13 mm socket and ratchet
• 5 mm Allen head socket or hex key (turbocharged cars only)
• 17 mm socket and ratchet or 17 mm wrench (turbocharged cars only)
• Flat-tip jeweler's screwdriver or straight probe

Removal

Normally Aspirated Cars

1. Remove the air filter cover, filter, and breather hose. Removing the cover and breather hose together is typically easiest.
2. Loosen the clamp holding the rubber inlet plenum boot to the air flow sensor.
3. Using the jeweler's screwdriver or straight probe, push back the ends of the wire retaining clip on the air flow sensor electrical connector until they rest on the sides of the connector. Slide the connector off the plug.

Note: Two electrical wires are secured to the air flow sensor via a small red plastic clip and L-bracket. Either try to pull the clip off the L-bracket, or remove the L-bracket from the air flow sensor using its single retaining bolt. Removing the bracket is recommended — attempting to pull the clip free can break it.

4. Remove the two 13 mm bolts at the front of the air filter housing (attaching the housing to the bracket at the radiator cross-member).
5. Remove the two 10 mm bolts at the back of the air filter housing (attaching it to a mounting bracket).
6. Lift the air flow sensor and air filter housing out of the car as a unit.

Turbocharged Cars

1. On top of the air filter housing, remove the screw for the metal strap that secures the filter housing to the turbocharger discharge pipe.
2. Loosen the two clamps on either end of the turbocharger discharge pipe (one behind the air filter housing, one near the top of the radiator).
3. Using a 17 mm socket or wrench, remove the banjo bolt on the turbocharger discharge pipe.

Caution: There are two metal seal rings on either side of the banjo connector. They can be dropped easily during removal and are difficult to retrieve if they fall in an awkward location. Handle carefully.

4. Remove the turbocharger discharge pipe from the car.

5. Using the jeweler's screwdriver or straight probe, push back the wire retaining clip on the air flow sensor electrical connector and slide the connector off the plug.

6. Using the 5 mm Allen head socket or hex key, loosen the filter housing retaining bolts. There are four bolts; the last one — behind the sensor housing on the right side of the air filter housing — is extremely difficult to access and may already be missing. The short end of a 5 mm hex key is often the only tool that can reach it. Partially remove bolts; do not fully remove them, as this simplifies reinstallation.

7. Loosen the clamp holding the rubber inlet plenum boot to the air flow sensor.

8. Lift the left side of the air filter housing and slide the entire assembly toward the left of the car as you lift it out.

Tip: Removing the filter housing inlet tube before extraction (by removing the two Phillips screws on top) makes lifting the housing out slightly easier.

Installation

Normally Aspirated Cars

1. Lower the air flow sensor/air filter housing assembly into the car, ensuring the air flow sensor outlet seats into the rubber inlet plenum boot.
2. Locate the filter assembly mounting brackets onto the studs on the upper radiator cross-member. Install and tighten the retaining nuts. Tighten the clamp on the rubber inlet plenum boot.
3. Ensure the wire retaining clip on the air flow sensor connector is properly positioned and slide the connector onto the sensor plug.
4. Connect the breather hose to the air filter housing and tighten the clamp.

Turbocharged Cars

1. Lower the air filter housing assembly into the car and slide the air flow sensor outlet into the rubber inlet plenum boot. As the housing descends, the Allen head mounting bolts should seat into their notched mounting brackets, ensuring correct alignment. If equipped with a timing belt cover breather hose, attach it to the bottom of the filter housing as the unit is lowered.

Note: Later models do not have the breather hose — the hose connection on the housing bottom is capped. Some early models may also have the breather hose connection on the timing belt cover capped from a previous update.

2. If the air filter housing inlet tube was removed, reinstall it using the two Phillips screws.
3. Tighten the air filter housing mounting bolts (5 mm Allen head) and the inlet plenum boot clamp on the air flow sensor.
4. Install the turbocharger discharge pipe. Insert the end into the rubber hose near the radiator first to simplify alignment. Tighten both hose clamps. Reinstall the banjo bolt connection — ensure both metal seal rings are placed on either side of the banjo connector before tightening.
5. On top of the air filter housing, install the metal strap for the turbocharger discharge pipe and secure with the retaining screw.
6. Ensure the wire retaining clip on the air flow sensor connector is properly positioned and slide the connector onto the sensor plug.