Cylinder Head and Gasket Kit 7247453 for Kubota D902 Bobcat MT55 MT85 – Service Part

Fleet Stocking Ready — Bobcat MT55 and MT85 cylinder head kits ship with matched gasket sets, supporting lifecycle replacement planning across mixed fleets.

Technical Specifications

Application Suitability

Why Overheated Kubota D902 Engines Need More Than a Gasket Swap

A warped cylinder head will destroy a new gasket within weeks of reassembly.

Fleet managers running Bobcat MT55 and MT85 units through urban demolition or quarry loading cycles frequently encounter coolant seepage into the oil sump. The immediate instinct is to replace the head gasket alone. Yet in many cases involving the Kubota D902 platform, the cylinder head itself has distorted beyond the serviceable flatness limit during repeated thermal cycling. Installing a fresh gasket against a deformed mating surface simply resets the failure clock. [NEED_CITE: cylinder head flatness tolerance and gasket sealing correlation in small displacement diesel engines]. This pattern accounts for a significant share of repeat teardowns in compact track loader fleets, where machine availability directly determines contract profitability. A complete Cylinder Head service part kit, pairing a new casting with its matched MLS gasket set, eliminates the guesswork and supports a single planned intervention rather than serial emergency repairs.

Where the Cylinder Head Sits in a Compact Track Loader’s Service Life

The cylinder head is not a routine wear item in the same sense as filters or belts, but it occupies a predictable position in the mid-to-late service life of a Kubota D902 engine. Units operating in stop-start municipal utility work accumulate thermal stress cycles far beyond what continuous-duty applications produce. By the time a Cylinder Head service part replacement becomes necessary, the engine has typically passed through several minor service intervals, and the cost of unplanned downtime begins to outweigh the component cost itself. Fleet operators who track hours and plan overhaul windows accordingly report meaningfully fewer reactive breakdowns.

Reading the Early Warning Signs Before a Full Failure

Coolant consumption without visible external leaks, a gradual rise in crankcase oil level, and faint white exhaust vapor during morning warm-up all point toward combustion chamber seal degradation. These symptoms often appear well before catastrophic overheating, providing a planning window for fleet maintenance teams. Replacing the Cylinder Head service part alongside the full gasket kit during this window avoids the compounding damage that occurs when coolant breaches the oil galleries. [NEED_CITE: diesel engine coolant ingestion failure progression and secondary bearing damage]. The cost of a planned head-and-gasket swap is modest relative to the crankshaft and bearing work that follows a neglected internal leak.

Material and Tolerance Details That Define Service Life

The high-silicon aluminum alloy casting, heat-treated to T6 condition, manages the concentrated thermal load around the combustion chamber and injector bore without localized softening. Valve seats induction-hardened to 45–48 HRC resist the recession that otherwise widens valve clearances and degrades compression over successive service intervals. The CNC-machined mating surface holds a flatness tolerance of ±0.02 mm, which is the critical factor in achieving reliable seal with the multi-layer steel head gasket. That MLS gasket, featuring Viton-coated stopper layers, maintains sealing integrity through the rapid temperature swings characteristic of urban demolition duty cycles. Copper-coated exhaust manifold gasket hardware rated to 900°C prevents the exhaust-side blowouts that commonly plague aftermarket kits using standard graphite materials.

The Compounding Cost of Reactive Cylinder Head Replacement

Fleets that treat cylinder head failure as a surprise event accumulate hidden costs across multiple dimensions. A machine down in a quarry loading zone misses its shift output while the team sources a head, then sources gaskets separately, then waits for both to arrive on mismatched lead times. The second teardown after a gasket-only repair that failed adds labor hours and replacement fasteners to the original bill. Grade 10.9 phosphate-coated head bolts are specified as single-use torque-to-yield fasteners on the D902 platform; reusing them after a failed first attempt introduces clamping force variability that accelerates the next failure. [NEED_CITE: torque-to-yield fastener reuse guidelines in diesel cylinder head assembly]. Planning the Cylinder Head service part and complete gasket kit as a single stock-keeping unit removes each of these friction points from future overhaul events.

What Makes This Supply Arrangement Work for Fleet Buyers

Own production on selected part lines and qualified sourcing on the remainder means this Cylinder Head service part and its gasket kit ship under one account and one warranty, regardless of which facility manufactured each component. The eight-category catalog allows a complete D902 overhaul list—pistons, bearings, seals, and head hardware—to consolidate into a single consignment rather than arriving in staggered shipments from multiple vendors. A minimum order of one piece supports the operator running a single MT55, while fleet-level pricing applies as quantities scale. The Guangzhou warehouse holds stock of common items for fast dispatch, and the technical team confirms fitment against engine serial number before the order ships. Cross-reference verification covers the superseded and alternate numbers associated with successive Bobcat MT85 production runs, so a legacy unit receives the correct variant without trial-and-error ordering.

Documentation & Verification

• Commercial invoice and packing list referencing 7247453 and included gasket sub-components
• Part compatibility sheet confirming Kubota D902 / D902-E3B-BC-1 engine variant match (reference only)
• Dimensional inspection record covering surface flatness and valve seat condition
• Six-month warranty terms covering manufacturing defects in casting and gasket materials
• Packing photographs showing kit completeness before crate closure
• HS code and customs documentation support for cross-border fleet supply

Service Interval & Stocking Guidance

• Inspect cylinder head flatness and valve seat condition at every major service interval beyond 2,000 hours
• Monitor coolant level trends weekly; unexplained loss signals internal seal degradation requiring planned head removal
• Stock one Cylinder Head service part kit per five MT55 or MT85 units to cover predictable mid-life overhaul demand
• Store kits in dry, temperature-stable conditions with gasket packaging sealed until installation day
• Replace Grade 10.9 head bolts at every head removal; never reuse torque-to-yield fasteners across service events

Request a Lifecycle Supply Quote

Provide your Bobcat machine model, engine serial number, and current operating hours to receive a stocking recommendation and replacement interval guidance aligned with your fleet’s duty cycle.

Frequently Asked Questions

Q: How often should the cylinder head be inspected on a Kubota D902 in a Bobcat MT55?
A: Inspect surface flatness and valve seat condition at every major service interval once the engine passes 2,000 operating hours. In stop-start urban demolition work, thermal cycling accelerates distortion, so shorter inspection intervals are prudent. Any unexplained coolant loss warrants immediate head removal and measurement regardless of hours logged.

Q: Is white exhaust smoke always a head gasket problem, or could the cylinder head itself be at fault?
A: White smoke indicates coolant entering the combustion chamber, which can originate from gasket failure, a cracked head, or a warped mating surface. On the Kubota D902, thermal distortion of the head is a frequent root cause. Replacing only the gasket without verifying head flatness risks rapid repeat failure within a short operating window.

Q: Can I replace just the gasket and keep the existing cylinder head?
A: Only if the head passes flatness measurement within ±0.02 mm and shows no valve seat recession beyond service limits. In practice, most D902 heads removed after an overheating event exceed these tolerances. Installing a new gasket against a warped surface creates uneven clamping load and predictable early leakage.

Q: How many cylinder head and gasket kits should a rental fleet keep in stock?
A: A practical baseline is one complete Cylinder Head service part kit for every five compact track loaders in active rotation. This covers the statistical likelihood of mid-life overhaul demand without tying up excessive inventory. Adjust upward if your fleet operates primarily in high-thermal-cycle applications like demolition or trenching.

Q: Will replacement parts for the Kubota D902 remain available as these machines age?
A: The D902 platform has a substantial installed base across multiple equipment brands, supporting continued aftermarket parts production. This Cylinder Head service part and gasket kit remains in active supply, with cross-reference coverage spanning superseded part numbers from successive Bobcat MT55 and MT85 production years.