Genuine Mazda PCV Valve / Cam Cover Breather Valve • BP05-13-890

Genuine Mazda BP05-13-890 PCV Valve / Cam Cover Breather Valve

Replacement Genuine Mazda positive crankcase ventilation valve for Mazda MX-5 Mk1 NA, Mk2 NB and Mk2.5 NB-FL models, subject to the engine-specific compatibility information shown in the vehicle table.

The PCV valve forms part of the engine’s crankcase ventilation and emissions-control system. It is fitted to the camshaft cover and regulates the flow of blow-by gases and oil vapour from the crankcase into the intake system, where they are burned during normal combustion.

During operation, a small quantity of combustion gas passes the piston rings and enters the crankcase. The PCV system allows these gases to leave in a controlled manner while helping maintain suitable crankcase pressure.

A blocked or restricted valve can allow crankcase pressure to increase, potentially contributing to oil leakage, increased oil consumption and contamination within the breather system. A valve stuck open may create an unintended intake air path and contribute to unstable idle, poor running, hissing noises or mixture-related faults.

There is one PCV valve fitted per engine. This listing supplies one Genuine Mazda PCV valve.

• Part type: Positive crankcase ventilation valve
• Common names: PCV valve / cam-cover breather valve / crankcase breather valve
• Mazda catalogue description: Valve, P.C.V.
• Primary use: Regulates crankcase vapour flow into the intake system
• Location: Cylinder-head / camshaft cover
• Quantity fitted per engine: 1
• Quantity supplied: 1 PCV valve
• Brand: Genuine Mazda
• Part No.: BP05-13-890
• Also referenced as: BP0513890
• Confirmed scope: Mazda MX-5 Mk1, Mk2 and Mk2.5 applications shown in the compatibility table
• Important exclusion: Not compatible with early Mazda MX-5 Mk2 1.8 models from 1998–2000 according to the confirmed application data

Possible signs of a PCV-system problem:

• Oil leakage from engine seals or gaskets
• Increased oil consumption
• Rough or unstable idle
• Whistling or hissing from the breather system
• Excessive oil contamination inside the intake tract
• Restricted, collapsed or oil-softened breather hoses
• Increased crankcase pressure

Fitment advice: This valve is confirmed across several MX-5 Mk1, Mk2 and Mk2.5 applications. It is not listed for early Mk2 1.8 models from 1998–2000 by the confirmed specialist application source. For later Mk2 and Mk2.5 1.8 variants, compare the original valve, cam-cover connection and Mazda part number before ordering.

Other items to consider: When replacing the PCV valve, inspect the rubber mounting grommet, crankcase-breather hoses, hose clips and intake connections. Brittle, split, blocked or oil-softened hoses and grommets should be replaced where necessary.

Useful tools / consumables: Suitable pliers, hose-clamp pliers, small flat trim tool, lint-free cloths and intake-safe cleaner. A replacement PCV-valve grommet may be required if the original rubber has hardened or split.

Difficulty guide: DIY Difficulty: Easy. The valve is normally accessible from the top of the engine. Care should be taken when removing aged breather hoses and the rubber mounting grommet, as they can become brittle with age and heat exposure.

Why Genuine Mazda? Genuine Mazda PCV valves are designed to provide the original flow-control characteristics, connection dimensions and sealing arrangement required by the engine’s crankcase ventilation system. Correct operation helps maintain controlled crankcase pressure and reliable engine running.

What’s in the box: One Genuine Mazda PCV valve / cam-cover breather valve, part number BP05-13-890.

Installation notes: Allow the engine to cool before removing the breather hose. Clean the surrounding cam-cover area so debris cannot enter the opening. Remove the old valve carefully and inspect the rubber grommet and hose for cracking, hardening or contamination. Install the replacement valve fully into the original mounting position, reconnect the hose securely and check the engine for vacuum leaks and correct idle operation.