Genuine Mazda BP5A-13-135 Upper Intake Manifold / Surge Tank Gasket
Replacement Genuine Mazda upper intake manifold gasket for Mazda MX-5 Mk2 NB 1.8 models with manual transmission, principally the early 1998–2000 application.
Mazda describes the upper section of the intake manifold as the surge tank or plenum chamber. This gasket seals the joint between that upper surge tank and the lower intake manifold, helping prevent unmetered air from entering the engine.
A secure, airtight intake-manifold joint is essential for stable engine vacuum and correct air-fuel control. The original gasket can harden, flatten or become damaged with age, particularly after the surge tank has been removed.
One gasket is fitted per vehicle, and this listing supplies one Genuine Mazda gasket. It should be replaced whenever the upper intake surge tank is removed rather than attempting to reuse the compressed original gasket.
Important fitment restriction: BP5A-13-135 is confirmed for early MX-5 Mk2 NB 1.8 models with manual transmission. Automatic-transmission models and Mk2.5 NB-FL vehicles use different intake-manifold gasket arrangements.
- Part type: Upper intake manifold gasket
- Common names: Surge-tank gasket / plenum gasket / upper inlet-manifold gasket
- Mazda catalogue description: Gasket, Surge Tank
- Location: Between the upper intake surge tank and lower intake manifold
- Engine application: 1.8-litre petrol engine
- Primary engine code: BP-4W
- Transmission application: Manual transmission
- Function: Seals the upper intake-manifold joint against vacuum and air leakage
- Quantity fitted per vehicle: 1
- Quantity supplied: 1 gasket
- Reusable component: No
- Upper intake manifold included: No
- Lower intake manifold included: No
- Throttle-body gasket included: No
- Lower manifold-to-cylinder-head gasket included: No
- Sealant included: No
- Brand: Genuine Mazda
- Part No.: BP5A-13-135
- MX-5 fitment: Early Mk2 NB 1.8 manual-transmission models
Possible signs of an intake-manifold gasket leak:
- Unstable, high or uneven idle speed
- Engine hesitation or poor low-speed response
- Lean-running fault codes
- Misfire, particularly at idle
- Whistling or hissing from the intake manifold
- Reduced engine performance
- Vacuum leak detected around the surge-tank joint
- Gasket visibly flattened, split or damaged after dismantling
Fitment advice: Confirm that the vehicle is an early Mk2 NB with the 1.8-litre engine and manual transmission. Do not assume compatibility with automatic-transmission or Mk2.5 NB-FL models, as Mazda used different gasket arrangements.
Replacement advice: Replace the gasket whenever the upper intake surge tank is removed. Reusing the original compressed gasket can result in an air leak even where it appears visually undamaged.
Other items to consider: Inspect the throttle-body gasket, lower intake-manifold gasket, vacuum hoses, PCV hoses, injector seals and any small coolant or air hoses disturbed during dismantling. Consider purchasing replacement hose clamps where the originals are corroded or weakened.
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. Access requires disconnection of intake hoses, vacuum lines and associated fittings before the surge tank can be lifted from the lower manifold.
Why Genuine Mazda? Genuine Mazda intake gaskets match the original port shape, bolt-hole alignment, compressed thickness and sealing-bead profile. Correct dimensions help maintain stable manifold vacuum and prevent unmetered air from entering the engine.
What’s in the box: One Genuine Mazda upper intake manifold / surge-tank gasket, part number BP5A-13-135.
Installation notes: Allow the engine to cool before dismantling the intake system. Label and disconnect the necessary intake hoses, electrical connectors and vacuum lines, then remove the surge-tank fasteners in accordance with the Mazda workshop procedure. Remove the old gasket and clean both mating surfaces without scratching or gouging them. Keep debris out of the open intake runners. Position the new gasket correctly over the locating points, refit the surge tank and tighten the fasteners progressively in the specified sequence and to the applicable Mazda torque. Reconnect every hose and connector, then start the engine and check for stable idle, air leaks and correct operation.
| Make | Model | Sub Variant | Chassis / Code | Years | Power (PS) | Engine Codes | Fuel | Transmission | Notes |
|---|---|---|---|---|---|---|---|---|---|
| Mazda | MX-5 | Mk2 NB – 1.8 | NB8C | 1998–2000 | 140 | BP-4W | Petrol | Manual | Upper intake manifold / surge-tank gasket; one fitted per vehicle; automatic and Mk2.5 models require different gaskets |
| Vehicle Manufacturer | OEM Reference Number |
|---|---|
| Mazda | BP5A-13-135 |