Genuine Mazda Cylinder Head Bolt • LF01-10-135

Genuine Mazda Cylinder Head Bolt

Replacement Genuine Mazda cylinder-head retaining bolt for Mazda MX-5 Mk3, Mk3.5 and Mk3.75 NC 1.8 and 2.0 models, plus Mazda MX-5 Mk4 ND/RF 2.0 models.

The bolt passes through the cylinder head and threads into the engine block. Together with the remaining cylinder-head bolts, it applies the clamping force required to secure the cylinder head and compress the head gasket evenly against the block.

Correct cylinder-head clamping is essential for maintaining combustion sealing and keeping the engine-oil and coolant passages separated. A damaged, stretched or incorrectly tightened bolt can produce an uneven clamping load and compromise the head-gasket seal.

Ten cylinder-head bolts are fitted per engine, while this listing supplies one Genuine Mazda bolt. Order a quantity of ten when replacing the complete set.

Important ND fitment restriction: This bolt is listed for the 2.0-litre MX-5 ND/RF engine. It is not listed for the 1.5-litre ND/RF engine.

• Part type: Cylinder-head retaining bolt
• Common names: Cylinder-head bolt / head bolt / engine head fastener
• Mazda catalogue description: Bolt, Cylinder Head
• Installation position: Through the cylinder head into the engine block
• Function: Applies the specified cylinder-head and head-gasket clamping load
• NC engine applications: 1.8-litre L8 and 2.0-litre LF petrol engines
• ND/RF engine application: 2.0-litre petrol engine
• Quantity fitted per engine: 10
• Quantity supplied: 1 bolt
• Complete bolt set included: No
• Cylinder-head gasket included: No
• Plain washers included: No
• Brand: Genuine Mazda
• Part No.: LF01-10-135
• MX-5 fitment: Mk3, Mk3.5 and Mk3.75 NC 1.8/2.0; Mk4 ND/RF 2.0

Typical reasons for replacement:

• Cylinder head removed for gasket replacement or engine repair
• Original bolt stretched beyond its permitted service measurement
• Bolt threads damaged, corroded or cross-threaded
• Drive head rounded or damaged during removal
• Bolt bent or visibly distorted
• Incorrect non-standard fastener previously installed
• Cylinder head or engine block being replaced
• Complete engine rebuild or refurbishment

Quantity advice: Ten bolts are required for a complete engine set. This listing supplies one bolt per order quantity.

Fitment advice: Confirm the engine application before ordering. This bolt covers the MX-5 NC 1.8 and 2.0 engines and the ND/RF 2.0 engine, but not the ND/RF 1.5 engine.

Replacement advice: Inspect and measure the removed cylinder-head bolts according to the applicable Mazda workshop procedure. Replace any bolt that is damaged or outside the permitted service specification.

Thread inspection: Clean and inspect the threaded holes in the engine block before installation. A replacement bolt will not correct damaged, contaminated or previously cross-threaded block threads.

Tightening advice: Install and tighten the complete cylinder-head bolt set only in the sequence and stages specified by Mazda. Incorrect tightening order, thread preparation or lubrication can distort the cylinder head or produce an uneven head-gasket seal.

Engine-work advice: When the cylinder head has been removed, inspect the head and block sealing surfaces for distortion, corrosion and mechanical damage. The cylinder-head gasket must be renewed before reassembly.

Other items to inspect: Check the cylinder-head gasket, locating dowels, camshaft-cover gasket, inlet-manifold gasket, exhaust-manifold gasket and associated timing components while the engine is dismantled.

Useful tools / consumables: Correct socket, calibrated torque wrench, angle gauge where required, thread-cleaning equipment, straight edge, feeler gauges and suitable parts cleaner.

Difficulty guide: DIY Difficulty: Advanced. Cylinder-head removal and installation require substantial engine dismantling, accurate component inspection and strict adherence to the Mazda workshop procedure.

Why Genuine Mazda? Genuine Mazda cylinder-head bolts match the specified thread, length, drive profile and fastener characteristics for the applicable engine. Correct hardware is essential for applying the intended and repeatable clamping load across the cylinder head.

What’s in the box: One Genuine Mazda cylinder-head retaining bolt, part number LF01-10-135.

Installation notes: Clean and inspect the bolt and engine-block threads before assembly. Start every bolt by hand to prevent cross-threading. Install and tighten the complete bolt set only in the sequence and stages specified in the applicable Mazda workshop procedure. Do not substitute general-purpose fasteners of unknown strength or dimensions.