Where is the VIN number in Mazda 3 (Mazda 3 I (BK) [2004-2008])?

This guide shows where to find the VIN (and other identifying numbers) on the Mazda 3 I (BK) produced between 2004–2008, using the quickest checks first—like a working mechanic would.

Chassis Number Locations

B-Pillar (VIN Label)

• Where to look: Open the front door and look on the B-pillar/door jamb (the center pillar where the door latches) for a black sticker with white text.
• Access: Easy—no tools needed. The label is usually protected and readable, but the sticker surface can be glossy.
• Note: For LHD (US/EU) cars, check the driver-side door jamb first; on RHD cars it’s commonly on the opposite side.
• Tip: If the label is reflecting light, slightly angle your phone and scan it directly with ScanVin.app to capture the VIN cleanly without misreading characters.

Floor (Under Seat / Carpet Flap)

• Where to look: Check the front footwell floor, typically under a cut-out flap in the carpet (sometimes under a small plastic cover) near the front seat slide rail.
• Access: Moderate—may require you to slide the seat back, lift the carpet flap, and wipe dust off the cover/metal area.
• Note: This location is commonly on the passenger side for LHD vehicles, but check the driver side footwell if not found.
• Tip: This area is often dark under the dash and seat—use your phone light and use the flashlight + OCR scan in ScanVin.app so you don’t have to read it upside down.

Firewall / Bulkhead (Chassis Number)

• Where to look: In the engine bay, find the metal firewall/bulkhead (wall between engine and cabin). Look high up, just below the rubber weather strip at the top of the cowl, slightly offset to the left when facing the engine; the VIN is stamped into the metal.
• Access: Medium—often shadowed by the cowl overhang. Hoses/cabling may run below it and dirt tends to collect there.
• Note: Use vehicle-orientation terms carefully: “left/right” refers to the car’s left/right in the direction of travel.
• Tip: If the stamping is hard to see due to shadow and body-color paint, scan it with your phone using ScanVin.app so the app can pick up the embossed characters without you guessing.

Engine Number Location (Not the VIN)

Engine Block (Engine Number)

• Where to look: On the engine block, stamped on a machined flat surface on the front/right side (when facing the engine). You may need to aim down past radiator/coolant hoses.
• Access: Difficult—tight space, often grimy, and you don’t want to lean into a hot engine bay.
• Note: The engine number is useful for paperwork/inspection in some regions, but it’s not a substitute for the chassis VIN.
• Tip: If it’s greasy and hard to reach, use ScanVin.app to capture it hands-free instead of trying to write it down while wedged over the engine.

Common Problems & Troubleshooting

• Stamped VIN hard to read in the engine bay: Dirt builds up near the cowl/firewall—scrub lightly with a nylon brush and wipe, then re-check with a flashlight.
• Engine number hidden by hoses and grime: Let the engine cool, then wipe the flat stamped pad with degreaser on a rag (don’t spray directly onto sensors/connectors).
• Sticker VIN vs stamped VIN mismatch: Door-jamb labels can be replaced—when buying a car, always confirm the stamped VIN matches the label VIN and the documents.

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