🔧 K900 - Engine Air Filter Replacement

Your A4 engine needs clean air to run smoothly and protect the throttle body and mass airflow sensor. Replacing the engine air filter is a quick maintenance job that helps fuel economy and keeps dirt out of the engine.

Difficulty Level: Beginner | Estimated Time: 0.25-0.5 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine to avoid burns from hot components.
• ⚠️ Keep tools and fingers clear of the radiator fan area; it can turn on unexpectedly.
• ⚠️ Do not spray cleaners into the air box or intake duct.
• ⚠️ Battery disconnect is not required for this service.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Flashlight
• Trim clip removal tool
• Phillips #2 screwdriver
• Flat-blade screwdriver (small)
• 10mm socket
• 1/4" drive ratchet
• Clean microfiber towel

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Engine air filter - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and support it securely.
• Assumption: Your A4 uses the standard airbox with clips/screws (common on this model).

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Locate the air filter housing

• Put on safety glasses and nitrile gloves.
• Use a flashlight and find the large black plastic air box (air cleaner housing) at the front-side of the engine bay, connected to the intake tube.

Step 2: Remove any cover or intake snorkel (if equipped)

• If a plastic engine cover blocks access, gently release its fasteners using a trim clip removal tool (a fork-shaped tool that pops plastic clips without breaking them).
• If an air snorkel/duct is clipped in place, release clips with a flat-blade screwdriver (small) and lift it out.

Step 3: Open the air filter box

• Release the metal or plastic latches by hand; if they’re tight, carefully pry with the flat-blade screwdriver (small).
• If your air box uses screws, remove them with a Phillips #2 screwdriver.
• If your air box uses small bolts instead, remove them using a 10mm socket and 1/4" drive ratchet, then reinstall later to Torque to 5 Nm (44 in-lbs).

Step 4: Remove the old air filter

• Lift the air box lid just enough to slide the filter out (you usually don’t need to remove the lid completely).
• Pull the filter straight out and note how it sits (rubber edge/gasket orientation).

Step 5: Clean the air box sealing surface

• Use a clean microfiber towel to wipe out loose dust and debris from the bottom of the air box.
• Wipe the air box rim where the filter seal sits; a clean seal helps prevent unfiltered air leaks.
• Tip: Don’t let dirt fall into the intake tube.

Step 6: Install the new air filter

• Place the new filter into the lower half of the air box with the rubber gasket seated evenly all the way around.
• Make sure the filter isn’t pinched and sits flat.

Step 7: Close and secure the air box

• Lower the air box lid and confirm it sits flush.
• Re-latch the clips by hand.
• If removed, reinstall screws with a Phillips #2 screwdriver.
• If removed, reinstall bolts with a 10mm socket and 1/4" drive ratchet and Torque to 5 Nm (44 in-lbs).

Step 8: Reinstall any ducts/covers

• Reinstall the snorkel/duct and secure clips using the flat-blade screwdriver (small) as needed.
• Reinstall any cover fasteners using the trim clip removal tool (press clips in straight so they don’t break).

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✅ After Repair

• Start the engine and let it idle for 15–30 seconds.
• Listen for hissing/whistling (a sign the air box lid isn’t sealed).
• Make sure no tools are left in the engine bay, then close the hood.

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💰 DIY vs Shop Cost

Shop Cost: $60-$140 (parts + labor)

DIY Cost: $15-$45 (parts only)

You Save: $45-$95 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.3-0.5 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.