Genuine Mazda Timing Chain Cover Blind Plug • 9XG0-99-667L

Genuine Mazda 9XG0-99-667L Timing Chain Cover Blind Plug

Replacement Genuine Mazda timing-chain cover blind plug for Mazda MX-5 Mk3, Mk3.5 and Mk3.75 NC models with 1.8 L8-VE or 2.0 LF-VE MZR petrol engines.

This hexagon-socket plug threads into an access opening in the engine timing-chain cover. Once installed correctly, it closes the opening and prevents engine oil escaping from the front-cover assembly.

The plug may be removed during timing-chain, tensioner or front engine-cover work. If it is not refitted securely, if its sealing compound has been disturbed or if the plug or cover threads are damaged, engine oil may leak into the engine bay.

The Genuine Mazda replacement is supplied ready to install with thread-locking or sealing compound applied. Avoid removing or contaminating the applied material before installation.

One plug is fitted at the relevant timing-cover access opening, and this listing supplies one Genuine Mazda plug.

• Part type: Timing-chain cover blind plug
• Common names: Timing-cover access plug / hexagon-socket plug
• Mazda catalogue description: Plug, Hexagon Socket / Plug, Blind
• Location: Engine timing-chain cover
• Function: Seals the timing-cover access opening
• Drive type: Internal hexagon socket
• Thread-locking or sealing compound: Pre-applied
• Quantity fitted at this position: 1
• Quantity supplied: 1 plug
• Separate sealing washer included: No
• Timing cover included: No
• Timing-chain components included: No
• Brand: Genuine Mazda
• Part No.: 9XG0-99-667L
• Earlier Mazda references: 9XG0-75-70X9 / 9XG0-99-66X9
• MX-5 fitment: Mk3, Mk3.5 and Mk3.75 NC 1.8 and 2.0 models

Typical reasons for replacement:

• Plug removed during timing-chain or tensioner work
• Engine-oil leakage from the timing-cover opening
• Original thread-locking compound disturbed or missing
• Hexagon socket rounded during removal
• Plug threads damaged or contaminated
• Original plug lost during engine maintenance
• Timing cover replaced or rebuilt

Fitment advice: This plug fits the original timing-chain cover used on Mazda MX-5 NC 1.8 L8 and 2.0 LF MZR engines. Confirm compatibility where an alternative engine, replacement timing cover or modified engine assembly has been installed.

Other items to consider: Inspect the timing-cover threads, surrounding sealing surface, timing-chain tensioner, chain guides, front crankshaft seal and adjacent cover joints. Any oil residue should be cleaned away so the exact source of leakage can be confirmed.

Useful tools / consumables: Correctly sized hex bit, ratchet, calibrated torque wrench, suitable degreaser, lint-free cloths and Mazda-approved thread sealant only where required by the applicable workshop procedure.

Difficulty guide: DIY Difficulty: Moderate. The plug is simple to install once accessible, but care is required because the surrounding timing cover is aluminium and can be damaged by cross-threading or excessive tightening.

Why Genuine Mazda? Genuine Mazda timing-cover plugs are manufactured to match the original thread, plug length, hexagon drive and sealing requirements. The correctly prepared replacement helps provide a secure, oil-tight closure without interfering with internal timing components.

What’s in the box: One Genuine Mazda timing-chain cover blind plug with pre-applied thread-locking or sealing compound, part number 9XG0-99-667L.

Installation notes: Allow the engine to cool and clean the area around the timing-cover opening before removing or installing the plug. Inspect the female threads for damage and remove oil or loose debris without allowing contamination to enter the timing-cover assembly. Avoid damaging or contaminating the pre-applied sealing compound. Start the replacement plug entirely by hand, then tighten it using the applicable Mazda specification and a correctly fitting hex bit. Clean the surrounding area and inspect for oil leakage after the engine has reached operating temperature.