Komatsuengine(no series)

Komatsu KT-1150-1B(S/N 114945-UP)

Maintenance schedule, common problems & OEM parts breakdown

Search live KT-1150-1B(S/N 114945-UP) parts

The Komatsu KT-1150-1B (S/N 114945-UP) is a bare industrial diesel engine listing, not a complete machine -- a Cummins-built KT1150/KT19-family turbocharged inline-six sold and tracked under Komatsu's own engine part numbering. It is most likely the engine fitted to the Komatsu HD325-3 rigid dump truck (chassis S/N 1501-up), a mechanical-era haul truck built roughly through the mid-to-late 1980s, ahead of the HD325-5 generation that followed into the 1990s and the later electronically controlled HD325-6/7/8 line. The engine runs a 159 x 159mm bore and stroke for roughly 19.0L displacement, with mechanical PT (Pressure-Time) fuel injection and no electronic engine controls -- pre-ECM, with no CID/FMI diagnostic codes, monitored only through analog warning lamps and gauges. Horsepower is reported anywhere from about 400 to 525hp depending on source and duty rating, with one HD325-3 spec sheet listing 438hp (327kW) gross; no source ties an exact figure specifically to the -1B suffix. Sibling engine-code listings exist for the same HD325-3 serial run -- an earlier -1A suffix and a later -1E suffix (explicitly Cummins-installed) -- pointing to running production changes within the KT-1150 code rather than separate engine families.

Across the HD325-3 build run, the engine code moved from -1A to -1B to -1E as serial numbers advanced, which reads as incremental running changes -- likely fuel pump calibration, injector, or accessory-drive updates -- rather than a displacement or architecture change. The bigger shift came at the platform level: Komatsu kept the mechanical, Cummins-sourced KT1150/KT19 engine through the HD325-3 and HD325-5 generations, then moved the HD325-6 and later trucks onto its own electronically controlled SAA6D140E engine family, retiring this engine line from new production. That history is exactly why the KT-1150-1B still matters in the used and parts market today: HD325-3-era haul trucks remain in service in mining and quarry fleets that value a mechanical engine with no ECM to fail, and the wider KT19/KT1150 architecture was used far beyond Komatsu -- in marine, power generation, and other industrial equipment -- so rebuild kits, injectors, and PT fuel-system parts stay available for long-term overhaul even though the engine itself is long out of production.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.

Komatsu KT-1150-1B(S/N 114945-UP) specifications

Engine

Engine family	Cummins-built inline-six diesel (KT1150 / KT19 family), carried under Komatsu's own KT-1150-1B part-numbering for this serial range. Not one of Komatsu's own D- or S-series engine designs.
Configuration	4-stroke, inline 6-cylinder, turbocharged. This KT-prefix rating is not charge-air aftercooled; a separate KTA-prefix version of the same block adds aftercooling.
Bore x stroke	159 x 159 mm (6.25 x 6.25 in)
Displacement	approx. 18.9-19.0 L (1,150 cu in)
Gross power	not separately published for the -1B rating; mechanical ratings documented across this KT1150/KT19 family commonly fall in the 300-390 kW (400-525 hp) band, with unrelated later electronic KTA19 ratings running higher. Treat as varies by rating/configuration -- confirm the exact horsepower plate on this serial range with your dealer.
Fuel system	mechanical Cummins pressure-time (PT) fuel pump; no electronic engine control
Emissions tier	pre-emissions mechanical diesel; no EPA/Tier certification (predates Tier 0)

Weights

Engine dry weight	approx. 2,070-2,110 kg (4,565-4,650 lb), as reported for the KT1150/KTA1150 six-cylinder block family; a rating-specific figure for -1B is not separately published
Host machine operating weight	not applicable -- this listing covers the engine only. No specific host machine model is confirmed in sourced documentation for this serial range
Ground pressure	not applicable (component engine, not a complete machine)

Dimensions

Overall engine length/width/height	not published in available documentation for this exact serial range -- verify with your dealer or the applicable Cummins spec sheet
Flywheel housing	SAE No. 1, per used-engine listings for this model

Performance

Rated/governed speed	approx. 2,100 rpm is typical for this engine family; the exact governed speed for the -1B rating is not confirmed
Torque	not confirmed for this specific rating
Vehicle performance figures	not applicable -- this is a component engine, not a complete machine, so travel speed/drawbar/lift figures do not apply

Service capacities (summary)

Fuel tank	not applicable -- tank sizing is set by the host machine, not the engine itself
Lubrication (oil) system	not confirmed to a reliable source for this exact rating -- figures seen in secondary listings were inconsistent and are not repeated here
Cooling system	water-cooled, radiator or heat-exchanger per installation; capacity not confirmed for this serial range

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

KT-1150-1B(S/N 114945-UP) fluids & capacities

System	Capacity	Recommended fluid
Engine crankcase (with filter) - KT-1150-1B	38 L (10.1 US gal)	Komatsu genuine engine oil (EO series). Multigrade 10W-30 or 15W-40 for temperate/cold starts, straight SAE 30 acceptable in sustained warm climates. Confirm exact grade band against the ambient-temperature chart in the OMM for this serial range, since this is a mechanical-era engine without ECM-driven oil spec updates.
Cooling system	133 L (35.2 US gal)	Komatsu genuine Supercoolant (ethylene-glycol based, corrosion-inhibited antifreeze/coolant), factory pre-mix or diluted per local climate for freeze protection. Change interval per OMM, typically every 2 years or 4000 hours.
Fuel tank	500 L (132.1 US gal)	ASTM No. 2-D diesel fuel for normal operation; No. 1-D diesel recommended in cold climates to prevent gelling/wax fallout.
Power train case (transmission and torque converter, wet)	Not separately confirmed for this serial range - verify with dealer or OMM refill table	Komatsu genuine powertrain oil (TO series), graded by ambient temperature per the OMM viscosity chart.
Final drives and differential (combined, both sides)	71 L (18.8 US gal) combined	Komatsu genuine gear oil (axle/final-drive spec, AXO or TO series depending on the OMM's designation for this era), graded by climate.
Hydraulic system (tank and circuit, hoist/steering/brake)	110 L (29.1 US gal)	Komatsu genuine hydraulic oil (HO series), viscosity grade selected by ambient temperature per the OMM chart (lighter grade for cold climates, heavier for sustained heat).
Grease (chassis and pin lubrication points, spec only)	Not applicable (spec only)	Komatsu genuine multipurpose lithium EP grease, NLGI grade 2, for pins, bushings and chassis lubrication points.

Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.

Komatsu KT-1150-1B(S/N 114945-UP) maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level; note any milky or fuel-thinned appearance that signals fuel dilution from extended idling on this mechanical PT engine Drain water and sediment from the primary fuel filter/water separator Check coolant level and top up with properly treated, SCA-balanced coolant Inspect the turbocharger for oil leaks and listen for abnormal shaft or bearing noise on startup Watch exhaust smoke color at startup and under load -- black smoke points to a PT fuel-system fault, not a sensor code Inspect drive belts, alternator wiring, and battery terminals since this pre-ECM charging system has no self-diagnostic warning
Every 250 h	Change engine oil and filter Test coolant SCA/corrosion-inhibitor concentration and add extender as needed Inspect and clean the primary fuel filter/water separator element Check the valve cover, gear housing, and PT fuel pump mounting for oil seepage Inspect turbocharger mounting hardware and connecting boots for cracking or looseness Check charging system output and clean battery terminals
Every 500 h	Replace primary and secondary fuel filters Replace the engine oil filter cartridge(s) Inspect and adjust fan belt tension Check the crankcase breather and air intake restriction indicator Pull an engine oil sample for wear-metal and fuel-dilution analysis, given this platform's documented camshaft and injector-lobe wear pattern Inspect the exhaust manifold and turbocharger housing for cracking
Every 1,000 h	Replace air filter element(s) or service per the restriction indicator Check and adjust valve lash and injector timing to the mechanical PT specification Inspect the camshaft-driven PT fuel pump governor linkage and injector plungers for wear Drain and inspect the cooling system for signs of wet-liner cavitation, and refresh SCA elements Check turbocharger shaft end play Inspect engine mounts and the vibration damper for cracking or bonding failure
Every 2,000 h	Drain, flush, and refill coolant, or perform a full SCA/extended-life coolant service Pull and inspect fuel injectors for plunger and lobe wear; recalibrate or replace as needed Bench-service the PT fuel pump governor and tachometer drive Sample coolant to check for early wet-liner cavitation pitting before it reaches the water jacket Torque-check cylinder head and manifold fasteners Inspect wiring harness connections and charging-system components for corrosion, since this pre-ECM engine has no fault-code warning for intermittent grounds
Every 4,000 h	Perform a top-end inspection if oil analysis or a compression check shows camshaft or injector-lobe wear trending Inspect camshaft lobes and tappets directly for the wear pattern this engine is known for under idling-heavy duty cycles Remove and recondition the turbocharger (bearing play, seal wear, wheel balance) Bench-test and calibrate the PT fuel pump Inspect wet cylinder liners for cavitation pitting at the coolant-side seal
Every 10,000 h	Schedule an inframe/overhaul evaluation covering cylinder liners, pistons, and connecting rod bearings Rebuild or replace the PT fuel pump and injector set together rather than piecemeal Recondition or replace the turbocharger Replace the vibration damper if it is at or beyond its service limit Inspect and renew cooling system hoses, water pump, and liner seals as part of the teardown

Servicing the KT-1150-1B(S/N 114945-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

Pull engine oil samples at every service interval and trend wear metals and fuel dilution; this mechanical PT platform has a documented camshaft and injector-lobe wear pattern tied to extended idling, and catching it in oil analysis avoids a surprise top-end teardown. Test coolant SCA/corrosion-inhibitor concentration on the same schedule to head off wet-liner cavitation pitting before it reaches the water jacket. With no ECM and no CID/FMI fault codes on this pre-electronic engine, physical sampling and hand-logged gauge readings -- oil pressure, coolant temperature, boost -- are the only predictive tools available.

Corrective & Common Repairs

Black smoke and power loss on this engine usually trace to the mechanical PT fuel system -- worn injector plungers, governor linkage wear, or pump calibration drift -- rather than a sensor fault, since there's no fault code to point at it. Charging-system complaints like slow cranking or dim lights are common on pre-ECM engines with analog regulators and aging alternator brushes; check these before assuming a starter or battery problem. Turbocharger bearing play shows up as smoke and sluggish throttle response. Coolant loss with no visible external leak often points to wet-liner seal seepage.

Overhaul & Rebuild Points

At inframe or overhaul time, check camshaft and injector lobes first given this platform's known idling-related wear pattern. Inspect wet cylinder liners for cavitation pitting at the coolant-side seal, which accelerates if SCA levels were ever allowed to lapse. Rebuild or recalibrate the PT fuel pump and injectors as a matched set rather than piecemeal. Turbocharger bearings and connecting rod bearings both carry heavy, sustained load in HD325-3 haul-truck duty and deserve close inspection at teardown before returning the engine to service.

Seasonal & Environment Servicing

This pre-electronic engine has no automatic cold-start strategy, so starting aids -- ether or a block heater -- and the correct seasonal oil viscosity matter more here than on later electronic engines. Confirm coolant SCA and freeze-point protection before winter; a lapsed inhibitor speeds up wet-liner cavitation in cold-cycle running. In hot, dusty mining or quarry environments, check air filter restriction and turbocharger inlet cleanliness more often than the standard interval. Extended idling in either climate accelerates the camshaft/injector wear and fuel dilution this engine is prone to.

KT-1150-1B(S/N 114945-UP) common service parts

Part number	Part	Notes
6721-81-1430	Plate? Caution,Fuel Filter (For Kt1150)	Fuel system service	Check fitment →
CUAR-13274	Fuel Filter Ass'Y	Fuel system service	Check fitment →
09645-20220	Plate? Instruction,Engine Oil Filter (French)	Lubrication service	Check fitment →
09645-70120	Plate? Instruction,Engine Oil Filter (Spanish)	Lubrication service	Check fitment →
CUWF-2053	Element,(Service Parts)	Scheduled service item	Check fitment →

Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.

KT-1150-1B(S/N 114945-UP) fault codes & troubleshooting

Code	Meaning	Likely cause	What to do
Engine Oil Pressure warning lamp (red)	Oil pressure switch has opened, indicating pressure below the safe minimum	Low oil level, worn oil pump, clogged oil filter, or failed pressure switch	Stop the engine immediately, check oil level and filter condition before restarting
Water Temperature warning lamp (red)	Coolant temperature switch has tripped on high coolant temperature	Low coolant level, blocked radiator, slipping or broken fan belt, thermostat stuck closed	Stop, let the engine idle cool down, check coolant level and radiator/fan belt before continuing
Air Cleaner Restriction indicator	Vacuum/restriction indicator shows intake airflow is obstructed	Dirty or clogged air filter element	Inspect and service or replace the air filter element
Charge (alternator) warning lamp	Charging circuit is not producing correct output	Loose or worn alternator drive belt, failed alternator, or wiring fault	Check belt tension and charging circuit wiring; test alternator output
Brake Air Pressure warning lamp/buzzer	Air pressure in the brake reservoir has dropped below the safe operating threshold	Air compressor malfunction, air system leak, or moisture in the lines	Idle the engine to rebuild air pressure and inspect the air system for leaks before moving the truck
Torque Converter Oil Temperature warning lamp	Torque converter fluid temperature has exceeded the safe limit	Low torque converter oil level, sustained overload/stall condition, or blocked oil cooler	Reduce load and idle the engine to cool the converter, then check fluid level and cooler for blockage

Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.

KT-1150-1B(S/N 114945-UP) attachments & work tools

Not an implement-carrying machine

The KT-1150-1B is a large inline six-cylinder diesel power unit, not a machine chassis. It has no boom, arm, blade, or quick-coupler system of its own, so there is no ground-engaging work-tool or attachment lineup to document for it directly.

Host-machine mounting only

This engine bolts into a host machine via its own flywheel housing, mounts, and drive coupling rather than accepting field attachments. Reported hosts for this power class include large crawler dozers, off-highway mining trucks, generator sets, marine propulsion packages, and large industrial pumps, so any 'attachments' belong to the host machine, not the engine.

Dozer-class host work tools (context only, not engine-specific)

Where this engine class powers large crawler dozers, the host machine typically runs a semi-U or U-blade and optional single- or multi-shank ripper sized to the dozer class. These are host-machine options and are not confirmed as specific to the KT-1150-1B(S/N 114945-UP) parts range itself — verify against the actual host machine's parts book.

Generator/pump/marine coupling arrangements

For genset, pump, and marine propulsion applications, the equivalent of a 'work tool' is the driven-end coupling: flywheel adapter to alternator, PTO shaft to pump, or reduction gearbox to propeller shaft. Exact coupling hardware is application-specific and set by the packager, not standardized by Komatsu for this engine model.

No factory guarding/attachment options documented

No brand attachment guide, dealer options sheet, or equipment database entry was found listing factory-installed work-tool guarding, coupler kits, or hydraulic attachment circuits for the KT-1150-1B(S/N 114945-UP) itself. Any guarding (belt guards, exhaust shields) is engine-accessory level, not work-tool related — verify with your dealer for the exact packaged configuration.

All KT-1150-1B(S/N 114945-UP) assemblies by section

Every catalogued assembly group for the Komatsu KT-1150-1B(S/N 114945-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Accessory

Komatsu : Kt-1150-1b(S/N 114945-Up) : Accessory : Accessory Drive

02***64	Bolt,(Cold Weather Spec.)	3
02***28	Washer,Spring	5
02***19	Key	2
66***20	Bushing	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Accessory : Air Compressor Piping

02***20	Washer	2
02***20	Washer,Spring	2
02***24	Washer,Spring	2
02***24	Washer,Radio Controlled Slag Handling	2

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Accessory : Air Compressor(#114945-115500)

02***70	Bolt	4
02***22	Bolt	2
02***20	Washer	4
02***24	Washer,Spring	3

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Accessory : Air Compressor(#115501-)

02***70	Bolt	4
02***22	Bolt	2
02***20	Washer	4
02***24	Washer,Spring	3

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Accessory : Baring Mechanism(#114945-117375)

02***24	Washer,Spring	6
02***04	Plug	1
CU***31	Gear Ass'Y	1
CU***19	Bushing	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Accessory : Baring Mechanism(#117376-)

CU***20	Spring	1
CU***52	Gear	1
CU***10	Bearing	1
CU***53	Shaft	1

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Cooling And Electrical Systems

Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Alternator

CU***71	Resistor	3
CU***76	Alternator A. (50a)	1
CU***06	Washer	1
CU***00	Grommet	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Alternator Mounting

02***95	Bolt	2
02***24	Washer,Spring	4
67***50	Link	1
CU***29	Bolt	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Cooling Fan

01***40	Bolt,(Dust And Dirt Protection)	6
01***36	Washer,Radio Controlled Slag Handling	6
01***38	Washer,Radio Controlled Slag Handling	6
02***45	Bolt	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Fan Hub(#114945-125726)

67***10	Shaft Ass'Y	1
67***80	Spring	1
67***90	Spacer	1
CU***11	Spacer	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Fan Hub(#125727-)

CU***11	Spacer	1
CU***28	Sleeve,(Not Shown)	1
CU***25	Support	1
CU***81	O-Ring	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Safety Relay And Drain Hose

60***30	Safety Relay A.,(A)(W/After Cooler)(S6d155-4b)	1
66***31	Elbow,(Not Shown)	1
67***00	Drain Hose Ass'Y	1
67***01	Hose Assembly, Drain (Engine Oil) (1)	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Starting Motor And Mounting

02***40	Washer,Spring	3
CU***94	Spacer	1
CU***95	Gasket	1
CU***59	Bolt	3

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Starting Motor(#114945-124060)

CU***43	Holder	3
CU***78	Nut	1
CU***36	Lead	1
CU***47	Washer	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Starting Motor(#124061-)

CU***69	Screw	12
CU***43	Holder	3
CU***38	Nut	1
CU***22	Plunger	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cooling And Electrical Systems : Water Pump

02***19	Bolt	1
02***95	Bolt	3
02***22	Bolt	1
02***32	Bolt,(With Joy Stick Steering)	1

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Cylinder Block

Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Cam Follower And Push Rod

02***64	Bolt,(Cold Weather Spec.)	12
02***24	Washer,Spring	24
CU***26	Cam Follower Ass'Y,Intake And Exhaust	12
CU***04	Gasket	6

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Camshaft

02***20	Washer	3
02***24	Washer,Spring	3
66***40	Washer	2
67***20	Gasket	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Crankshaft And Vibration Damper

02***32	Washer,Spring	6
CU***70	Main Metal Ass'Y	1
CU***73	Main Metal Ass'Y	1
CU***59	Gear	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Cylinder Block

66***70	Pin,Dowel (See Fig.0201 Or 0202)	2
67***60	Pin,Dowel	2
CU***55	Block Ass'Y,(Thin Flange)	1
CU***28	Shim? 0.23mm	0

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Flywheel Housing

01***48	Washer,Spring? Single Flange	8
02***22	Bolt	4
02***44	Bolt	8
02***20	Washer,Radio Controlled Slag Handling	8

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Gear Housing(#114945-117375)

02***44	Bolt,(Hexagon Head)	5
02***32	Bolt,(Hexagon Head)	8
02***20	Washer	9
02***24	Washer,Spring	34

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Gear Housing(#117376-)

CU***03	Bolt	1
CU***23	Insert	1
CU***05	Bolt,(12 Point Head)	6
CU***75	Bolt,(12 Point Head)	4

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Oil Pan

01***25	Bolt,(Sandy? Dusty Terrain Spec.)	2
01***50	Bolt	1
01***29	Washer,Spring (Cold Weather Spec.)	5
01***30	Washer,Spring(Sandy?Dusty Terrain S.)	3

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Block : Piston And Connecting Rod

CU***50	Piston	1
CU***53	Connecting Rod Ass'Y	6
CU***65	Bushing	1
CU***44	Metal? 1.00mm (Us)	12

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Cylinder Head

Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Air Cleaner

04***10	Ring,See Fig. K4010-65a0	1
60***80	Clamp	1
60***90	Valve,Vacuator	1
60***90	Nut,Wing (K26)	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Air Intake Manifold

02***24	Washer,Spring	29
CU***36	O-Ring	2
CU***03	Bolt	2
CU***66	Plug	2

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Cylinder Head

02***10	Plug (Heater Not Installed)	1
66***10	Pin,Dowel? Cylinder Head	2
66***20	Screw,Adjusting	12
67***50	Plug, Expansion	8

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Exhaust Manifold

66***30	Washer	4
67***10	Gasket	6
CU***86	Manifold,Exhaust? Front	2
CU***94	Washer	20

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Rocker Lever And Housing

02***13	Plug	1
07***13	Hose	2
07***59	Clamp,See Fig. K4010-05a0	1
66***70	Clip,(For Slag Handling)	2

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Thermostat

02***25	Bolt,(Europe Spec.)	2
02***64	Bolt,(Cold Weather Spec.)	2
02***57	Bolt	3
02***25	Bolt	2

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Turbocharger Mounting

02***24	Washer,Spring	4
CU***NF	Hose	1
CU***91	Clip	1
CU***12	Bolt	2

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Turbocharger(#114945-124060)

CU***56	Plate	1
CU***83	Plate	1
CU***59	O-Ring	1
CU***65	Nut	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Cylinder Head : Turbocharger(#124061-)

CU***05	Shaft Ass'Y	1
CU***56	Plate	1
CU***59	O-Ring	1
CU***48	Turbocharger Ass'Y	1

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Fuel System

Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Cold Starting Aid (Mechanical Type)

67***21	Cable,Control	1
67***31	Cylinder Ass'Y	1
67***51	Tube	1
67***61	Elbow	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Fuel Filter And Manifold

02***32	Bolt	2
67***80	Adapter	1
67***30	Plate? Caution,Fuel Filter (For Kt1150)	1
67***30	Plate? Caution,(Japanese-English)	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Fuel Injector

67***30	O-Ring,Injector	1
67***60	Gasket	1
67***90	Clip	1
67***70	Ball,Check	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Pt Fuel Pump (1/4)

01***20	Washer,Spring	1
02***38	Bolt	1
02***04	Nut	1
66***40	Washer	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Pt Fuel Pump (2/4)

CU***64	Seal (K2)	2
CU***60	Washer,Spring	2
CU***01	Shaft	1
CU***26	Washer	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Pt Fuel Pump (3/4)

CU***-A	Shim? 0.010inch	0
CU***32	Plunger	1
CU***33	Plunger	1
CU***-B	Shim? 0.005inch	0

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Pt Fuel Pump (4/4)

66***20	Shield,Fuel	1
66***30	Spring,Valve	1
66***60	O-Ring,Shut Down Valve	1
66***30	Knob	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Pt Pump And Piping(#114945-123835)

02***25	Bolt,(Europe Spec.)	1
02***20	Washer	3
02***24	Washer,Spring	1
02***28	Washer,Spring	4

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Fuel System : Pt Pump And Piping(#123836-)

02***32	Bolt	1
02***24	Washer,Spring	1
02***04	Elbow,(With Afc)	1
CU***50	Ferrule	2

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Lubricating Oil System

Komatsu : Kt-1150-1b(S/N 114945-Up) : Lubricating Oil System : Bypass Filter

02***19	Bolt	8
02***32	Bolt	2
02***32	Bolt	2
02***06	Nut,Radio Controlled Slag Handling	8

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Lubricating Oil System : Lubricating Oil Pump

02***32	Bolt	3
02***64	Bolt	1
02***02	Bolt	1
02***20	Washer	3

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Lubricating Oil System : Oil Cooler

02***24	Washer,Spring	23
CU***77	Oil Cooler Ass'Y	1
CU***67	Element	2
CU***20	Plug	1

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Komatsu : Kt-1150-1b(S/N 114945-Up) : Lubricating Oil System : Oil Filter

01***29	Washer,Spring (Cold Weather Spec.)	4
01***16	Washer,(With Shoe Slip Control)	4
02***89	Bolt	1
02***16	Plug	2

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KT-1150-1B(S/N 114945-UP) serial number reference

On the HD325-3, the truck's own PIN/chassis serial plate is on the left front of the frame. The engine serial number plate for the KT-1150-1B is separate, mounted on top of the cylinder head cover. This engine generation predates Komatsu's later 3-character alphanumeric PIN-prefix scheme (used on newer electronic PC/WA/HD models), so both the chassis serial (1501-up) and engine serial (114945-up) are read as plain sequential numbers rather than a coded prefix.

Prefix	Identifies	Notes
no letter prefix (plain S/N 1501-and-up)	Komatsu HD325-3 rigid dump truck - sole confirmed host	Only host machine tied to the KT-1150-1B by parts documentation. HD325-3 chassis is numbered 1501-and-up with no 3-character PIN-style prefix; the KT-1150-1B engine run of S/N 114945-and-up corresponds to this chassis range. This is a mechanical, pre-ECM era engine/truck pairing from the 1984-1990 HD325-3 production run. Confirm with dealer for exact chassis-to-engine serial breakpoints if servicing a specific unit.

Frequently asked questions

What engine is the Komatsu KT-1150-1B (S/N 114945-UP)?

It's a Cummins-built KT1150/KT19-family turbocharged inline-six diesel, sold under Komatsu's own engine part numbering. Bore and stroke are 159 x 159mm for roughly 19.0L displacement, with mechanical PT (Pressure-Time) fuel injection and no electronic controls -- no ECM, no CID/FMI fault codes, just analog warning lamps and gauges.

What is the operating weight of the KT-1150-1B?

Dry weight for the KT19/KT1150 engine block family runs approximately 2,070 to 2,110 kg, though that figure isn't published specific to the -1B rating -- treat it as a family-level approximation. This is the bare engine only; the host HD325-3 haul truck it's most likely fitted to carries a much larger operating weight of its own as a complete machine.

What replaced the KT-1150-1B?

Within the HD325-3 build run itself, Komatsu made running changes to the engine code -- from -1A to -1B to -1E across advancing serial blocks -- rather than a full model change. At the platform level, Komatsu eventually moved the HD325 line off this Cummins-sourced mechanical engine entirely, switching the HD325-6 and later generations to its own electronically controlled SAA6D140E engine family.

What KT-1150-1B(S/N 114945-UP) owners discuss

How reliable is the KT1150 engine used in the KT-1150-1B, based on what long-term users and rebuilders say?

Owners and rebuilders who have run this Cummins-built inline-six describe it as a heavy, slow-turning industrial engine that holds up well past several working lifetimes if fuel, oil, and coolant maintenance stay on schedule. It's a purely mechanical PT fuel system engine with no ECM, so the common failure points are wear items - injectors, camshaft, cylinder liners - rather than electronics. Note that this KT-1150-1B is the turbocharged, non-aftercooled version of the 1150-cubic-inch family; discussion about the aftercooled KTA1150 variant used in higher-output mining trucks and generator sets can report different boost and coolant behavior, so treat that as a related but separate configuration, not a direct match. Engines that see steady load and regular oil analysis routinely outlast the machines they're bolted to; engines run mostly at idle or with neglected coolant service wear out early.

What's the camshaft wear issue people bring up with this engine family, and what causes it?

Users report premature camshaft wear at the injector lobes on 1150-family engines that spend a lot of time idling. Extended idle combined with fuel dilution of the crankcase oil is the pattern most often cited - diluted oil loses film strength at the cam-to-tappet contact, and the injector lobes take the load hardest. Symptoms show up as rough idle, injector timing drift, or metal in the oil filter before outright failure. Keep idle time down, watch for injector O-ring leakage that lets fuel wash into the sump, and pull oil samples on a fixed interval so dilution shows up before the cam does. Have your dealer verify camshaft and lifter condition with a borescope or teardown before committing to a rebuild.

What does black smoke or a sudden loss of power usually point to on this engine?

On PT-fuel mechanical engines like this one, black smoke under load almost always means the engine isn't getting enough air for the fuel it's burning - a dirty air filter, a failing turbocharger, or injection timing that has drifted out of spec. There's no electronic boost or timing control to self-correct, so a marginal turbo or a plugged air cleaner shows up immediately as smoke and a flat power curve rather than a stored fault code. Check turbo shaft play and boost pressure first, then verify injector timing with the dial-indicator method before assuming the fuel pump itself is at fault.

What coolant maintenance mistake shortens the life of this engine's cylinder liners?

This engine uses wet cylinder liners, and letting the supplemental coolant additive fall out of range is the lapse operators mention most for shortened liner life. Low additive lets liner-wall cavitation pit through the liner from the coolant side; overdosing additive after a coolant change without also changing the coolant causes its own scaling and water pump seal problems. Test additive concentration at every oil change interval, not just when the coolant looks dirty, and change - don't just top off - coolant on the recommended schedule.

What wear patterns are typical for the tires, suspension struts, and frame on this class of haul truck?

On rigid-frame haul trucks in the HD325 class this engine powers, the pattern operators watch for is uneven front tire wear from misaligned steering or worn king pins, nitrogen-charged suspension struts losing charge and sagging on one corner, and frame cracking near the hoist mounts and rear axle housing on trucks that have run overloaded or unevenly loaded for years. None of this is engine-specific, but a truck with a tired engine has often also seen a tired frame and suspension - inspect both together on an older unit.

What electrical or sensor issues come up, given this is a mechanical, pre-electronic engine?

This engine has no ECM and very few sensors - the electrical side is limited to starting, charging, and gauge-panel wiring, and that's where the complaints are. The most common issues are corroded alternator terminal connections that kill the charge light and can stop the starter-lockout relay from working correctly, and harness connectors at the monitor panel corroding enough to give false low-oil-pressure or high-temperature warnings. The engine itself won't throw a fault code, so gauge readings are the only warning system available - keep those connections clean. Have your dealer verify any oil pressure or temperature warning against a mechanical gauge before assuming it's wiring.

What should I check before buying a used KT-1150-1B(S/N 114945-UP)?

Pull an oil sample and check for fuel dilution and metal content before anything else - it's the earliest warning for the camshaft and liner wear this engine family is known for. Check supplemental coolant additive level and coolant condition, since low-additive liner cavitation is invisible from outside. Verify boost pressure and watch for exhaust smoke under load to catch a tired turbo or drifted injector timing. Confirm the engine has actually run under load regularly rather than idled, since mostly-idle hours are more likely to show the injector-lobe camshaft wear pattern. On the host truck, check tires, suspension struts, and frame near the hoist mounts for the wear common to this truck class. Have your dealer verify compression, injector timing, and camshaft condition before final purchase.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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