Genuine Mazda Magnetic Rear Differential Oil Drain Plug • 0810-17-121

Genuine Mazda 0810-17-121 Magnetic Rear Differential Oil Drain Plug

Replacement Genuine Mazda magnetic differential oil drain plug for all Mazda MX-5 generations, including Mk1 NA, Mk2 and Mk2.5 NB, Mk3 NC and Mk4 ND/RF models.

The plug is installed in the lower drain opening of the rear differential housing. It is removed during servicing to allow the used differential oil to drain before the casing is refilled through the separate filler opening.

The plug incorporates a magnetic tip that attracts fine ferrous wear particles suspended in the lubricant. This helps prevent metallic debris from continuing to circulate through the differential bearings, crown wheel and pinion.

A light metallic paste on the magnet can be normal during routine servicing. Larger particles, sharp fragments or unusually heavy deposits should be investigated because they may indicate internal bearing or gear wear.

The plug may require replacement if its threads, sealing face or tool-engagement area are damaged, or if the magnetic section is broken, heavily corroded or no longer secure.

• Part type: Magnetic rear differential oil drain plug
• Mazda catalogue description: Plug, Magnet
• Primary use: Closes the differential oil drain opening
• Additional function: Collects fine ferrous wear particles from the lubricant
• Location: Lower area of the rear differential housing
• Quantity per differential: 1
• Quantity supplied: 1 magnetic drain plug
• Sealing washer included: No
• Brand: Genuine Mazda
• Part No.: 0810-17-121
• Also referenced as: 081017121 / 810-17-121
• Fitment note: Confirmed for all Mazda MX-5 generations

Important: This listing is for the magnetic drain plug only. The sealing washer is not included and should normally be replaced whenever the plug is removed.

Fitment advice: Although Mazda uses this magnetic plug in numerous differential, transmission and axle assemblies, its confirmed position on Mazda MX-5 models is the rear differential drain opening. Where a replacement or non-standard differential has been fitted, compare the original plug and thread before ordering.

Other items to consider: Consider purchasing a new sealing washer, the correct specification and quantity of differential oil, and a replacement filler plug if the existing plug is damaged. Inspect the differential casing, breather, oil seals and filler-plug threads during servicing.

Useful tools / consumables: Suitable socket or spanner for the installed plug, ratchet or breaker bar, torque wrench, drain container, fluid pump, cleaning brush, lint-free cloths and manufacturer-specified differential oil.

Difficulty guide: DIY Difficulty: Easy to Moderate. The vehicle must be raised and supported safely while remaining level for accurate refilling. Always confirm that the differential filler plug can be removed before opening the drain plug.

Why Genuine Mazda? Genuine Mazda differential plugs are manufactured to match the original thread, sealing face and housing arrangement. The integrated magnet is positioned to collect ferrous debris while maintaining compatibility with the original differential casing and sealing washer.

What’s in the box: One Genuine Mazda magnetic rear differential oil drain plug, part number 0810-17-121. Sealing washer not included.

Installation notes: Clean the differential housing around the drain and filler openings before removal. Loosen the filler plug first, then position a suitable container beneath the differential and remove the drain plug. Clean and inspect the magnetic tip for debris. Fit a new sealing washer to the replacement plug, tighten it to the specification applicable to the differential and refill with the correct lubricant. Refit the filler plug and inspect both openings for leakage.