Genuine Mazda Exhaust Manifold to Mid-Pipe Fastening Spring • BP48-40-582A

Genuine Mazda Exhaust Manifold to Mid-Pipe Fastening Spring

Replacement Genuine Mazda exhaust-joint fastening spring for Mazda MX-5 Mk3, Mk3.5 and Mk3.75 NC models fitted with 1.8- or 2.0-litre petrol engines.

This compression spring fits over the corresponding exhaust fastening bolt at the connection between the exhaust manifold or front catalytic-converter assembly and the centre exhaust pipe.

The spring maintains controlled clamping pressure across the exhaust joint while allowing a small amount of movement as the exhaust system expands, contracts and moves with the engine. This helps preserve the joint seal without creating an excessively rigid connection.

Two fastening springs are fitted per vehicle, one on each exhaust-joint bolt. This listing supplies one Genuine Mazda spring, so order a quantity of two when renewing both sides of the joint.

Important contents information: This listing is for the fastening spring only. The exhaust bolts, nuts, joint gasket and exhaust pipes are not included.

• Part type: Exhaust-joint compression spring
• Common names: Exhaust bolt spring / manifold spring / converter-to-pipe spring
• Mazda catalogue description: Spring
• Location: Exhaust manifold/front converter to centre pipe joint
• Function: Maintains controlled clamping pressure at the flexible exhaust connection
• Quantity fitted per vehicle: 2
• Quantity supplied: 1 spring
• Exhaust bolt included: No
• Retaining nut included: No
• Exhaust joint gasket included: No
• Exhaust manifold included: No
• Centre exhaust pipe included: No
• Brand: Genuine Mazda
• Part No.: BP48-40-582A
• Previous Mazda reference: BP48-40-582
• MX-5 fitment: All Mk3, Mk3.5 and Mk3.75 NC 1.8 and 2.0 models

Typical reasons for replacement:

• Spring heavily corroded
• Spring cracked or fractured
• Spring permanently compressed or distorted
• Original spring missing
• Exhaust joint dismantled during repair
• Exhaust manifold or centre-pipe replacement
• Exhaust leak from the manifold-to-pipe connection
• Previously fitted incorrect or solid mounting hardware

Quantity advice: Two springs are used at the exhaust joint. This listing supplies one spring per order quantity.

Fitment advice: BP48-40-582A fits the sprung exhaust connection used across 1.8- and 2.0-litre MX-5 NC models. Confirm that the required component is the spring rather than the associated bolt, nut or sealing gasket.

Replacement advice: It is advisable to inspect and replace both springs together where their condition is similar. Check the associated bolts, threads, retaining nuts, exhaust flanges and sealing gasket before reassembly.

Exhaust-leak advice: Replacing the springs alone may not correct a leak caused by a failed gasket, distorted flange, cracked pipe or damaged fastening bolt. The complete joint should be inspected after dismantling.

Other items to consider: Inspect the two exhaust-joint bolts, retaining nuts, sealing gasket, manifold flange, centre-pipe flange, exhaust hangers and surrounding heat shields.

Useful tools / consumables: Socket and spanner set, penetrating fluid, wire brush, suitable exhaust support, calibrated torque wrench and high-temperature exhaust-joint consumables where specified by Mazda.

Difficulty guide: DIY Difficulty: Moderate. Exhaust fasteners are frequently exposed to severe heat and corrosion and may require careful removal to avoid bolt or flange damage.

Why Genuine Mazda? Genuine Mazda fastening springs match the original spring rate, free length, diameter and material specification. Correct spring characteristics maintain the intended exhaust-joint pressure while permitting controlled movement of the system.

What’s in the box: One Genuine Mazda exhaust manifold-to-mid-pipe fastening spring, part number BP48-40-582A.

Installation notes: Allow the exhaust system to cool completely and support the centre pipe before loosening the joint. Apply penetrating fluid to corroded hardware and remove the retaining fasteners carefully. Inspect the bolts, springs, gasket and mating flanges. Position the replacement spring over the correct bolt and assemble the joint evenly on both sides. Tighten the fasteners progressively using the applicable Mazda procedure, ensuring that the gasket remains correctly seated and the exhaust system is not placed under tension. Check the joint for leaks after installation.