Genuine Mazda Exhaust Manifold to Front Pipe Fastening Nut • 9YB0-41-015

Genuine Mazda Exhaust Manifold to Front Pipe Fastening Nut

Replacement Genuine Mazda exhaust fastening nut for all Mazda MX-5 Mk3, Mk3.5 and Mk3.75 NC models fitted with the 1.8-litre or 2.0-litre petrol engine.

The nut is used at the spring-loaded exhaust flange connection between the exhaust manifold or catalytic-converter outlet and the front or mid exhaust pipe.

This joint uses two fastening nuts together with the corresponding bolts and compression springs. The springs maintain pressure against the exhaust sealing joint while allowing limited movement as the exhaust system heats, cools and moves with the engine.

Two nuts are fitted per vehicle. This listing supplies one Genuine Mazda nut, so order a quantity of two when renewing both fastening positions.

• Part type: Exhaust flange fastening nut
• Common names: Exhaust manifold nut / front-pipe nut / catalytic-converter flange nut
• Mazda catalogue description: Nut
• Location: Exhaust manifold or catalytic-converter outlet to front exhaust pipe
• Function: Retains the spring-loaded exhaust flange connection
• Thread specification: M10 x 1.25
• Hex / spanner size: Approximately 14mm
• Quantity fitted per vehicle: 2
• Quantity supplied: 1 nut
• Exhaust flange bolt included: No
• Compression spring included: No
• Exhaust gasket included: No
• Brand: Genuine Mazda
• Part No.: 9YB0-41-015
• MX-5 fitment: Mk3, Mk3.5 and Mk3.75 NC models

Typical reasons for replacement:

• Original nut heavily corroded or seized
• Hex rounded during exhaust removal
• Threads damaged or cross-threaded
• Nut missing following previous exhaust work
• Exhaust manifold or front-pipe replacement
• Exhaust joint dismantled to renew the gasket or springs

Fitment advice: This nut is used at the spring-loaded front exhaust connection on MX-5 NC models. Confirm that the original exhaust manifold, catalytic converter and front-pipe arrangement remains fitted where the vehicle has an aftermarket exhaust system.

Quantity advice: Two nuts are required for the complete exhaust flange connection. This listing supplies one nut per order quantity.

Replacement advice: Inspect both nuts, both flange bolts and both compression springs whenever the joint is dismantled. Corroded or distorted fastening hardware can prevent the exhaust joint from clamping evenly.

Other items to consider: Inspect the exhaust flange gasket, spring bolts, compression springs, manifold flange and front-pipe flange. Replace the gasket if there are signs of exhaust leakage, crushing or heat damage.

Useful tools / consumables: Suitable socket and spanner set, penetrating fluid, wire brush, thread-cleaning tools and calibrated torque wrench.

Difficulty guide: DIY Difficulty: Moderate. The nut itself is straightforward to replace, but underbody access and exhaust corrosion may make removal difficult.

Why Genuine Mazda? Genuine Mazda exhaust hardware matches the original thread pitch, nut dimensions and material specification required for the spring-loaded flange connection. Correct hardware helps maintain even clamping and reliable exhaust sealing.

What’s in the box: One Genuine Mazda exhaust manifold-to-front-pipe fastening nut, part number 9YB0-41-015.

Installation notes: Allow the exhaust system to cool fully before beginning work. Apply penetrating fluid to corroded hardware and support the exhaust pipe before removing the original nut. Inspect the bolt, spring, gasket and both flange surfaces. Start the replacement nut by hand to prevent cross-threading, then tighten the two flange positions progressively and evenly to the applicable Mazda specification. Start the engine and check the joint for exhaust leakage after installation.