Performance Air Filter for Citroen Xsara / Xsara Picasso, Peugeot 206, 306 (1998-2010)

The Wrench Time

• Estimated Time: 30-45 Minutes
• Difficulty: 3/10 - Tight C5 engine bay clearance and fragile, heat-soaked plastic latches.

Tools You Will Need

• 10mm socket or box wrench (battery disconnect)
• Flathead screwdriver (standard and stubby)
• T25 Torx driver (shroud removal, if equipped)
• 90-degree pick tool (for stubborn harness latches)
• Shop vacuum or clean microfiber cloth (for airbox debris cleanup)

Phase 1: Removing the Factory Part from your 1997-2006 Audi A6 RS6 4.2L

1. Disconnect the Battery: Pop the cowl cover and use a 10mm wrench to loosen the clamp on the negative battery terminal. Move the cable aside to prevent accidental contact, avoiding short circuits and spurious ECU trouble codes.
2. Clear Bay Plastics: Remove the passenger-side plastic cosmetic engine covers by turning the quarter-turn fasteners 90 degrees by hand or with a flathead screwdriver. Lift the covers straight up to expose the airbox assembly tucked against the passenger fender.
3. Disconnect the MAF Sensor Harness: Locate the MAF sensor mounted directly inline with the airbox outlet pipe. Push the harness plug forward slightly, depress the locking release tab, and slide the electrical connector off. Inspect the connector housing pins for any green corrosion or oil contamination.
4. Loosen the Intake Accordion Duct: Using a flathead screwdriver, loosen the worm-gear clamp securing the rubber intake inlet hose to the MAF housing. Gently work the rubber duct off the hard plastic housing without wrenching on the surrounding brittle vacuum lines.
5. Unlatch Airbox Housing Clips: Release the four spring-steel retaining clips holding the upper and lower airbox shells together. Use a stubby flathead screwdriver to carefully pry the blind bottom clips free if your fingers cannot reach them.
6. Extract the Factory Filter: Lift the upper airbox lid upward and toward the center of the engine bay. Carefully pull the old paper element out of the lower airbox tray, ensuring torn paper fibers or loose road gravel do not fall into the clean-air intake duct.

Phase 2: Installing the Performance Air Filter

1. Clean the Airbox Sump: Before fitting your new filter into the 1997-2006 Audi A6 RS6 4.2L housing, use a shop vacuum or a clean microfiber cloth to remove all accumulated sand, leaves, and road grit resting in the lower airbox tray.
2. Seat the New Performance Filter: Align the Performance Air Filter into the lower housing. Press down along the entire perimeter with your fingers to confirm the flexible rubber or polyurethane sealing bead sits fully flush inside the factory groove. An uneven bead will cause an unmetered air leak (vacuum leak) and trip lean codes.
3. Re-mate the Airbox Shells: Carefully guide the upper airbox lid back over the filter, ensuring the lower alignment tabs hook into their slots before clamping. Snap all four metal tension clips back into position with your fingers until you feel a positive mechanical lock.
4. Reattach Intake Duct & Reconnect MAF: Slide the rubber intake accordion duct back over the MAF housing outlet. Secure the worm-gear clamp firmly with your flathead screwdriver, ensuring you do not overtighten and crush the plastic housing. Reconnect the MAF electrical plug until you hear an audible click. Reinstall your decorative engine covers.
5. Terminal Reconnection & ECU Settle Cycle: Reconnect the negative battery terminal and cinch it tight with a 10mm wrench. Turn the ignition key to the "ON" position (do not crank) for 15 seconds to let the throttle body align. Start the engine and do not touch the gas pedal for at least 20 seconds while the ECU reads fresh idle airflow data and stabilizes fuel trims.

Disclaimer: This is a general guide provided for the 1997-2006 Audi A6 RS6 4.2L. Always refer to your factory service manual for exact torque specifications and safety procedures.