Quick Info
Model
450, 452
Estimated Cost
€10-€15
Difficulty
Beginner
Time Required
15 Minutes
Safety Notes
Positioning: The filter is located deep in the passenger footwell. Be prepared for some "light gymnastics" to reach it.
Plastic Parts: Be gentle with the plastic nuts and clips; they can become brittle with age.
Air Flow Direction: Pay close attention to the arrow on the filter indicating the Air Flow direction to ensure the filtration works correctly.
Step-by-Step Guide
Introduction
The cabin filter on the Smart Roadster is often neglected because it is hidden deep behind the passenger carpet and the foam tire repair kit block. Unlike modern cars where the filter is usually behind a glovebox, the Roadster requires you to remove part of the insulation and a large foam insert.
Replacing this filter once a year or every 15,000 km prevents the buildup of bacteria, pollen, and dust. If your windows fog up easily in the rain or the air feels "stuffy," a dirty filter is almost always the culprit. Upgrading to an active charcoal filter is highly recommended as it also neutralizes exterior odors and exhaust fumes.
Prep the Passenger Area
Slide the passenger seat all the way back to maximize your workspace. Remove the floor mat to gain access to the main floor carpeting and insulation.
Removing the Foam Block (Tire Repair Kit)
Under the passenger footwell, you will find a large foam block containing the compressor and tire sealant.
Use a 10mm socket to unscrew the plastic nut holding the block in place.
Pop out the side plastic trim near the door sill to allow the carpet to lift more easily.
Accessing the Filter Housing
Pull the floor carpet and insulation back. Slide the entire foam block out of the car. You will now see a narrow, vertical black housing toward the center console.
Accessing the Filter Housing
At the top of the housing, there is a plastic cap/locking clip.
Unclip the top fastener and remove the cap.
Grip the edge of the old filter and slowly pull it downward and out.
Note: If the filter is very dirty, expect some leaves and debris to fall out of the housing.
Installing the New Filter
Take your new filter
Crucial: Check the AIR FLOW arrow. The arrow must point toward the interior of the cabin/the blower motor (usually toward the center of the car).
Carefully slide the filter into the slot until it is fully seated.
Reassembly
Replace the plastic housing cap and ensure it clicks securely. Reinsert the foam block, tighten the 10mm nut, and put the side trim and carpet back in place.
