Genuine Mazda Camshaft / Rocker Cover Gasket – 1.8 • BP05-10-235C

Genuine Mazda Camshaft / Rocker Cover Gasket – 1.8

Replacement Genuine Mazda camshaft-cover gasket for Mazda MX-5 Mk1 NA 1.8 models and early Mk2 NB models fitted with the non-VVT 1.8-litre petrol engine.

The moulded gasket fits between the camshaft or rocker cover and the upper surface of the cylinder head. It seals engine oil inside the cylinder-head assembly while preventing water, dust and other contaminants from entering around the cover.

The gasket also incorporates the sealing sections around the spark-plug wells. Age and repeated heat cycles can cause the material to harden, flatten or crack, allowing oil to leak around the outside of the cover or collect around the spark plugs.

One gasket is fitted per engine, and this listing supplies one complete Genuine Mazda camshaft-cover gasket.

Important fitment restriction: BP05-10-235C is for the 1.8-litre non-VVT engine used in Mk1 NA models from 1994 and early Mk2 NB models up to 2000. Mk2.5 1.8 VVT, factory turbo and 1.6-litre engines use different gasket specifications.

• Part type: Camshaft / rocker-cover gasket
• Common names: Valve-cover gasket / head-cover gasket / cam-cover seal
• Mazda catalogue description: Gasket, Head Cover
• Installation position: Between the camshaft cover and cylinder head
• Function: Seals engine oil within the upper cylinder-head assembly
• Engine application: 1.8-litre non-VVT petrol engine
• Primary engine codes: BP-ZE / BP-4W
• Spark-plug-well sealing sections: Incorporated into the moulded gasket
• Quantity fitted per engine: 1
• Quantity supplied: 1 complete gasket
• Camshaft cover included: No
• Cover bolts or sealing washers included: No
• Sealant included: No
• Brand: Genuine Mazda
• Part No.: BP05-10-235C
• Previous Mazda references: BP05-10-235 and BP05-10-235B
• MX-5 fitment: Mk1 NA 1.8 and early Mk2 NB 1.8 models up to 2000

Typical signs of gasket deterioration:

• Engine oil leaking around the edge of the camshaft cover
• Oil collecting inside the spark-plug wells
• Burning-oil smell from oil reaching hot engine or exhaust components
• Visible oil staining down the cylinder head
• Gasket hardened, flattened, cracked or permanently compressed
• Oil contamination around the ignition leads or spark plugs
• Camshaft cover removed during engine servicing

Fitment advice: Confirm that the vehicle has the 1.8-litre non-VVT engine. Do not select the gasket solely by vehicle generation, because later Mk2.5 VVT and factory turbo models use different camshaft-cover arrangements.

Replacement advice: The gasket compresses during installation and should normally be replaced whenever the camshaft cover is removed. Reusing an aged or previously compressed gasket can result in an oil leak after reassembly.

Inspection advice: Check the gasket groove, cylinder-head mating surface and spark-plug wells for hardened gasket material, oil deposits and damage. Inspect the camshaft cover for cracks or distortion caused by previous overtightening.

Sealant advice: Apply suitable sealant only at the specific joint locations required by the Mazda workshop procedure. Do not coat the complete gasket with sealant, as this can prevent correct seating.

Other items to consider: Inspect the camshaft-cover fixing seals, crankcase-breather hoses, PCV valve, oil-filler-cap seal, ignition leads and spark plugs while the cover is removed.

Useful tools / consumables: Socket set, calibrated low-range torque wrench, plastic gasket-removal tool, suitable parts cleaner, lint-free cloths and Mazda-approved sealing compound where specified.

Difficulty guide: DIY Difficulty: Moderate. Access is generally straightforward, but careful surface preparation, gasket positioning and low-torque tightening are necessary to avoid leaks or cover damage.

Why Genuine Mazda? Genuine Mazda camshaft-cover gaskets match the original cover groove, cylinder-head profile and spark-plug-well sealing positions. Correct moulding and material characteristics help provide an even oil-tight seal without requiring excessive fixing-bolt torque.

What’s in the box: One Genuine Mazda camshaft / rocker-cover gasket, part number BP05-10-235C.

Installation notes: Allow the engine to cool and remove the ignition leads, breather hoses and other components required to access the camshaft cover. Remove the cover carefully, then clean the gasket groove and cylinder-head mating surface without damaging them. Fit the new gasket fully into the cover groove and apply approved sealant only at the locations specified by Mazda. Refit the cover and tighten the fasteners progressively in the correct sequence using the applicable Mazda procedure. Reconnect all removed components and inspect for oil leakage after the engine has run and cooled.