Bobcat New GCT GK25 Engine Service Manual DSB4533E00 – LPG Lift Truck Engine Repair Guide

Description

Bobcat New GCT GK25 Engine Service Manual

This is the full Bobcat service manual for the New GCT GK25 engine, published under document number DSB4533E00 in September 2023. It is the workshop reference for the 2,488 cc four-cylinder LPG engine fitted to Cushion 1 ton series and Cushion 2 ton series lift trucks, and it walks a technician through everything from routine maintenance to a complete engine overhaul. Whether you are chasing a rough idle, pulling the cylinder head, or setting valve clearance on a warmed engine, the procedure and the numbers you need are in these pages.

The manual is written around the GK25 as a system, not just as a block of iron. Fuel delivery, ignition, electronic throttle control, emissions hardware and the ECU are all treated as part of the same machine, because on an electronically controlled LPG engine they are. That is why the document runs to nine sections rather than the usual engine-only layout.

File Details

• Manual type: Engine service manual (maintenance, repair, disassembly and assembly)
• Brand: Bobcat
• Engine: New GCT GK25
• Document number: DSB4533E00
• Edition date: September 2023
• Publisher: Bobcat Company
• Language: English
• Page count: 1,018 pages
• File format: PDF

Chapters Covered

The manual is organised into nine coded sections. Rather than a flat list, here is what each section actually gives you:

• General Information (GI) — how to use the manual, definition of terms, abbreviations and standards, definition of units, safety and quality precautions, draining coolant, disconnecting fuel piping, removing and disassembling, inspection and replacement, assembly and installation, angle wrench use on cylinder head bolts, power tool precautions, liquid gasket application, special service tools
• Maintenance (MA) — inspection and adjustment specifications, maintenance schedule, oils and capacity, tightening the head bolt, re-tightening manifold bolts and nuts, intake/exhaust valve clearance adjustment, cooling fan belt inspection and adjustment, oil and oil filter replacement, engine coolant replacement, compression pressure inspection, spark plug inspection, standard bolt tightening torque, tightening torque for engine parts
• Engine Troubleshooting (ET) — basic troubleshooting, trouble starting and idling, engine noise, knocking, rattling sound, excess oil consumption, oil leaks, overheating, decreased output
• Engine Mechanical (EM) — adjustment values, engine removal and installation, engine disassembly, inspection and adjustment, engine assembly, PTO device, timing chain, camshaft, piston and connecting rod, crankshaft, cylinder head, oil pan, oil pump
• Lubrication & Cooling Systems (LC) — lubrication system diagram, hydraulic pressure, cooling system diagram, water pump, thermostat, filling LLC into the cooling system, cooling system schematic, troubleshooting
• Engine Fuel (EF) — emission control system, troubleshooting, electronic controlled system diagrams, throttle chamber removal and installation, gasoline fuel injector, LPG injector, LPG solenoid, LPG fuel pressure sensor, relief valve, vaporizer, blowby gas recirculation device
• Engine Control (EC) — engine trouble diagnosis, entire overview, system diagram, sensor and actuator control items, ECU component parts location, circuit diagram, control unit input and output, engine wiring reference value list, diagnosis chart by symptom, fail-safe function, DTC list, service tool, active test and support, basic inspection, component part inspection
• Engine Electrical (EE) — troubleshooting, starter motor (dry type), alternator inspection and removal
• GCT Engine Service Tool (EST) — safety rules, system components, start and end, setting, communicating with the ECU, data monitor, diagnosis, active test and support, ECU information, ECU reprogram, checking saved data, error messages and corrective actions

Taken as a whole, the document is a complete teardown-to-reassembly workflow for one specific engine. The mechanical section gives you the order of operations and the clearances; the control section gives you the wiring values and the fault codes; the maintenance section gives you the intervals and the torque figures. You are not left to interpolate between a generic engine book and a separate wiring diagram — the relationships are already laid out.

Engine Specifications You Will Be Working To

The GK25 is a 2,488 cc OHV four-cylinder with a bathtub combustion chamber, an 89.0 mm bore and an 83.0 mm stroke, running a compression ratio of 8.7. Standard compression pressure is listed at 1.45 MPa at 250 min-1. Valve clearance hot is 0.38 mm on both intake and exhaust. Idle ignition timing is 0 degrees BTDC. Engine speed control is by ECU and electronic throttle, and the fuel specification is LPG in the 20P to 100P range.

What Makes This Manual Useful in the Bay

The GCT GK25 is an electronically governed LPG engine, and that changes what a service manual has to cover. You cannot set the idle with a screwdriver and a tachometer the way you would on a mechanical governor engine — the manual addresses this directly with its throttle learning clear, accelerator pedal released position learning, air-fuel ratio learning clear and fuel pressure removal procedures, all executed through the GCT Engine Service Tool. The final section of the manual is dedicated to that software, screen by screen, so the diagnostic side of the job is not a mystery.

On the mechanical side, the tightening sequence for the cylinder head bolts runs in five stages, ending with an angular tightening of 82 to 87 degrees using an angle wrench. The manual is explicit that the head gasket is not reusable once tightened, that the bolts need anti-rust oil on the threads and shoulder, and that the dowels must be checked before the head goes back on. Those details matter. Skipping them is how heads leak.

The troubleshooting section is written by symptom rather than by component, which is how a technician actually approaches a machine that will not start. It splits cranking failures from fuel failures from ignition failures, and points you to the specific inspection for each.

Who This Manual Is For

This is written for the service technician, mechanic or workshop working on the GCT GK25 engine in a Bobcat lift truck. It assumes you have the tools — including the special service tools the manual calls out by part number — and it assumes you understand why a torque wrench and an angle wrench are not interchangeable. If you are rebuilding, resealing, diagnosing or simply maintaining a GK25, this is the document that tells you the sequence, the values and the limits.

Get the Complete GK25 Engine Repair Guide

Everything needed for a full engine job is here: the disassembly and assembly order for the cylinder head, camshaft, timing chain, pistons, connecting rods, crankshaft, oil pan, oil pump and PTO device; the inspection and adjustment values with both standard and limit figures; the torque tables for standard bolts and for individual engine parts; the DTC list with malfunction detection conditions; and the diagnostic procedures behind the engine warning lamp.

Correct procedures and correct specifications are what separate a repair that lasts from a comeback. The head bolt sequence, the valve clearance setting on a hot engine, the piston-to-cylinder clearance at room temperature, the crankshaft end play, the main bearing oil clearance measured with Plastigage — these are all in the manual with their tolerances. Guessing at any of them is expensive.

IMAGES PREVIEW

Delivery is instant. This is a PDF download, no shipping, no waiting for a parcel. The file opens on any device — laptop, tablet or phone — and every page can be printed if you prefer a paper copy on the bench. Buy it once and you have the full 1,018-page reference for the life of the engine.