Genuine Mazda Exhaust Manifold Locking Nut • 9XG0-36-627L

Genuine Mazda 9XG0-36-627L Exhaust Manifold Locking Nut

Replacement Genuine Mazda exhaust manifold locking nut for Mazda MX-5 Mk3, Mk3.5 and Mk3.75 NC models with 1.8 or 2.0 MZR petrol engines.

This nut threads onto one of the cylinder-head exhaust studs and clamps the exhaust manifold firmly against the exhaust ports and manifold gasket.

Correct and even clamping is essential for maintaining a gas-tight seal between the exhaust manifold and cylinder head. The locking design helps resist loosening under repeated engine vibration and heating and cooling cycles.

Exhaust-manifold hardware operates in a severe environment and is continuously exposed to high temperatures, moisture and road salt. The original nuts can become heavily corroded, seized, rounded or weakened after repeated heat cycles.

There are seven nuts fitted per MX-5 NC engine. This listing supplies one Genuine Mazda nut, so select the required quantity according to the repair being carried out.

• Part type: Exhaust manifold locking nut
• Mazda catalogue description: Nut, Exhaust Manifold
• Primary use: Secures the exhaust manifold to the cylinder head
• Location: Exhaust face of the cylinder head
• Quantity fitted per MX-5 NC engine: 7
• Quantity supplied: 1 nut
• Exhaust stud included: No
• Exhaust manifold gasket included: No
• Brand: Genuine Mazda
• Part No.: 9XG0-36-627L
• Also referenced as: 9XG036627L
• Earlier Mazda references: 9XG0-36-621M / 9XG0-36-62X9
• MX-5 fitment: Mk3, Mk3.5 and Mk3.75 NC 1.8 and 2.0 models

Possible reasons for replacement:

• Heavy corrosion or metal deterioration
• Rounded or damaged hex faces
• Nut seized onto the exhaust stud
• Damaged or cross-threaded internal thread
• Loss of the original locking resistance
• Exhaust manifold removal or replacement
• Exhaust gas leakage caused by uneven manifold clamping

Fitment advice: This nut is used on the cylinder-head exhaust-manifold studs of Mazda MX-5 NC 1.8 and 2.0 MZR engines. Confirm the original mounting position where an aftermarket manifold, replacement cylinder head or modified exhaust system has been fitted.

Other items to consider: Inspect all seven manifold nuts, the exhaust studs, manifold gasket, manifold flange and cylinder-head sealing face. Replace any stud that is stretched, heavily corroded or has damaged threads.

Useful tools / consumables: Suitable deep socket, extension bars, penetrating fluid, calibrated torque wrench, wire brush, stud-removal equipment and suitable high-temperature assembly compound where permitted by the Mazda workshop procedure.

Difficulty guide: DIY Difficulty: Moderate to Advanced. Access may be restricted by exhaust shields and surrounding engine components. Corroded nuts can seize onto the studs, and excessive force may snap a stud in the cylinder head.

Why Genuine Mazda? Genuine Mazda exhaust hardware is manufactured to match the original thread, nut dimensions, strength specification and high-temperature locking characteristics. Correct hardware helps maintain even manifold clamping and compatibility with the original exhaust studs.

What’s in the box: One Genuine Mazda exhaust manifold locking nut, part number 9XG0-36-627L.

Installation notes: Allow the engine and exhaust system to cool fully before beginning work. Apply penetrating fluid to corroded hardware and remove the old nuts progressively to reduce the risk of damaging the manifold or studs. Clean and inspect the stud threads and manifold sealing faces. Fit the gasket and manifold squarely, start all nuts by hand and tighten them progressively in the applicable Mazda sequence to the specified torque. Check for exhaust leakage after installation.