Genuine Mazda Engine Oil Filler Cap with Seal • R2AA-10-250

Genuine Mazda Engine Oil Filler Cap with Seal

Replacement Genuine Mazda engine-oil filler cap for all Mazda MX-5 Mk3, Mk3.5 and Mk3.75 NC and Mk4 ND/RF engine variants.

The oil filler cap fits to the opening in the engine cylinder-head or cam-cover assembly and closes the engine-oil filling point after servicing or topping up.

The cap helps prevent engine oil from escaping and protects the lubrication system from dirt, water and other external contamination. It is supplied with its sealing ring already fitted and assembled.

One oil filler cap is fitted per engine, and this listing supplies one complete Genuine Mazda cap with seal.

• Part type: Engine-oil filler cap
• Common names: Oil cap / rocker-cover oil cap / cam-cover filler cap
• Mazda catalogue description: Cap, Oil Filler
• System: Engine lubrication system
• Installation position: Oil-filling aperture in the cylinder-head or cam cover
• Function: Closes and seals the engine-oil filling point
• Quantity fitted per engine: 1
• Quantity supplied: 1 complete cap
• Sealing ring included: Yes, fitted and assembled
• Engine oil included: No
• Brand: Genuine Mazda
• Part No.: R2AA-10-250
• Compact reference: R2AA10250
• MX-5 fitment: Mk3/Mk3.5/Mk3.75 NC and Mk4 ND/RF
• Additional Mazda applications: Various Mazda 2, Mazda 3, Mazda 5, Mazda 6 and CX models

Typical reasons for replacement:

• Original oil cap missing
• Seal hardened, flattened, split or damaged
• Oil staining or seepage around the filler opening
• Cap cracked or physically damaged
• Threads or retaining features worn
• Cap no longer tightens or releases correctly
• Incorrect universal cap previously installed
• Cap contaminated with sludge or damaged during servicing

Quantity advice: One oil filler cap is fitted per engine. This listing supplies one complete cap with its sealing ring assembled.

Fitment advice: This cap is shared across numerous Mazda petrol-engine applications. The confirmed MX-5 application covers all NC and ND/RF engine variants.

Seal inspection: Replace the cap if its sealing ring is split, hardened, distorted or permanently compressed. A damaged seal may allow oil vapour or liquid oil to escape around the filler opening.

Filler-opening inspection: Clean the mating surface around the oil-filling aperture before fitting the replacement cap. Remove dirt and old oil deposits without allowing contamination to enter the engine.

Installation advice: Position the cap squarely on the filler opening and turn it until it is correctly seated and secure. Do not force or cross-thread the cap.

Oil-level advice: Check the engine-oil level using the dipstick or the applicable Mazda procedure after topping up. Do not exceed the specified maximum oil level.

Diagnostic advice: Oil around the filler cap may also be caused by overfilling, excessive crankcase pressure, a blocked ventilation system or oil spilled during servicing. Inspect the surrounding area before assuming that the cap is the sole cause.

Other items to inspect: Check the cylinder-head or cam-cover sealing area, crankcase-ventilation hoses, oil dipstick seal and surrounding engine components for leakage or contamination.

Useful tools / consumables: No specialist tools are normally required. Suitable cleaning cloths and an engine-safe degreaser may be useful when cleaning the filler-cap area.

Difficulty guide: DIY Difficulty: Easy. The cap can normally be replaced by hand without removing surrounding components.

Why Genuine Mazda? Genuine Mazda oil filler caps match the original filler-neck connection, sealing arrangement and engine-cover design. The supplied assembled seal provides the correct interface with the Mazda engine-oil filling aperture.

What’s in the box: One Genuine Mazda engine-oil filler cap with assembled sealing ring, part number R2AA-10-250.

Installation notes: Allow the engine to cool where necessary and clean around the oil-filling aperture before removing the existing cap. Prevent dirt or loose debris from entering the engine. Inspect the filler opening, position the replacement cap squarely and tighten it by hand until securely seated. Run the engine and inspect the area for oil seepage.