Genuine Mazda Lower Intake Manifold Gasket – 1.8 • BP4W-13-111

Genuine Mazda BP4W-13-111 Lower Intake Manifold Gasket – 1.8

Replacement Genuine Mazda lower intake manifold gasket for Mazda MX-5 Mk2 NB and Mk2.5 NB-FL models fitted with the 1.8-litre petrol engine.

The gasket fits between the lower intake manifold and the cylinder head. It seals the intake ports and prevents unmetered air entering the engine after the airflow has been measured.

A secure intake-manifold seal is essential for stable manifold vacuum, consistent idle quality and correct air-fuel control. The original gasket can flatten, harden or become damaged through age, heat cycles or manifold removal.

One gasket is fitted per vehicle, and this listing supplies one Genuine Mazda gasket. It should be replaced whenever the intake manifold is removed rather than attempting to reuse the compressed original component.

Engine restriction: BP4W-13-111 is for MX-5 NB and NB-FL models with the 1.8-litre engine. The 1.6-litre NB and Mk1 NA use different intake manifold gaskets.

Component distinction: This is the lower manifold-to-cylinder-head gasket. The separate gasket between the upper surge tank and lower intake manifold varies according to model year, intake-manifold design and transmission.

• Part type: Lower intake manifold gasket
• Common names: Inlet manifold gasket / manifold-to-head gasket / intake-port gasket
• Mazda catalogue description: Gasket, Inlet Manifold
• Position: Lower intake manifold
• Location: Between the intake manifold and cylinder head
• Engine application: 1.8-litre petrol engine
• Primary engine codes: BP-4W / BP-Z3
• Transmission application: Manual or automatic
• Function: Seals the intake ports against vacuum and unmetered-air leakage
• Quantity fitted per vehicle: 1
• Quantity supplied: 1 gasket
• Reusable component: No
• Intake manifold included: No
• Surge-tank gasket included: No
• Throttle-body gasket included: No
• Injector seals included: No
• Sealant included: No
• Brand: Genuine Mazda
• Part No.: BP4W-13-111
• MX-5 fitment: Mk2 NB and Mk2.5 NB-FL 1.8 models

Possible signs of an intake manifold gasket leak:

• High, unstable or uneven idle speed
• Whistling or hissing from the intake manifold
• Lean-running fault codes
• Misfire, particularly at idle
• Hesitation or poor low-speed response
• Reduced engine performance
• Vacuum leak detected around the manifold-to-head joint
• Gasket visibly split or damaged after dismantling

Fitment advice: Confirm that the vehicle has the 1.8-litre engine before ordering. The gasket is shared across the Mk2 and Mk2.5 1.8 applications, but the upper surge-tank gasket is a separate component and must be selected for the exact manifold and transmission arrangement.

Replacement advice: Replace the gasket whenever the lower intake manifold is separated from the cylinder head. Reusing the original compressed gasket can result in an intake leak even where it appears visually serviceable.

Other items to consider: Inspect the upper surge-tank gasket, throttle-body gasket, injector seals, PCV hoses, vacuum hoses and any coolant hoses disturbed during removal. Consider purchasing replacement hose clamps where the originals are weakened or corroded.

Useful tools / consumables: Socket and spanner set, calibrated torque wrench, hose-clamp pliers, plastic gasket scraper, lint-free cleaning materials and suitable intake-system cleaner.

Difficulty guide: DIY Difficulty: Moderate to Advanced. Access requires removal of the intake manifold assembly and careful disconnection of the associated hoses, wiring, fuel-system components and vacuum connections.

Why Genuine Mazda? Genuine Mazda intake manifold gaskets match the original intake-port profile, fastener alignment, compressed thickness and sealing design. Correct dimensions help maintain stable manifold vacuum and prevent unmetered air entering the engine.

What’s in the box: One Genuine Mazda lower intake manifold gasket, part number BP4W-13-111.

Installation notes: Allow the engine to cool before dismantling the intake system. Relieve fuel-system pressure where fuel components must be disconnected, then label and remove the necessary hoses, wiring connectors and vacuum lines. Remove the intake manifold following the applicable Mazda procedure. Clean both mating surfaces carefully without scratching the aluminium or allowing debris into the intake ports. Position the new gasket correctly over the locating points, refit the manifold and tighten the fasteners progressively in the specified sequence and to the applicable Mazda torque. Reconnect every hose, electrical connector and fuel connection, then check for fuel leaks, stable idle and intake-air leakage before returning the vehicle to service.