Komatsu SA12V140-1R(S/N 11640-UP)

The SA12V140-1R is a water-cooled, turbocharged and aftercooled V12 diesel engine. It typically drives mechanical drivetrains or powershift transmissions depending on the host machine configuration. Hydraulic systems in machines equipped with this engine series are known to lose performance when hot due to decreased oil viscosity and internal leakage in pumps or control valves. Shared hydraulic supply issues, such as low oil level or degraded Komatsu HO hydraulic oil, often cause all functions (boom, arm, bucket, swing, travel) to become weak simultaneously. Engine speed drop under heavy hydraulic load indicates the hydraulic system is placing excessive load on the engine or the engine cannot produce expected power. The engine relies on mechanical jerk-pump fuel injection in many configurations, making it less sensitive to electronic sensor failures but sensitive to fuel quality and waxing in cold climates. Fuel injection pump governors vary by serial range, including Zexel PS7S mechanical governor, Komatsu high-pressure electrohydraulic control, and Bosch full-authority electronic control; the exact system fitted varies by build/serial range. Verify the specific governor type against the shop manual for the serial range in question. Power output varies by configuration/series; rated gross/net kW and HP should be verified against the shop manual for the specific serial range. Displacement is 30.5 liters (30,480 cc) with a bore of 140 mm and stroke of 165 mm. Dry weight is approximately 3,100-3,300 kg depending on configuration. Flywheel horsepower ranges from 574 kW (770 HP) to 603 kW (808 HP) at 2,000 rpm depending on the specific application and governor type. Low idling speed ranges from 700 to 1,250 rpm depending on the application. Minimum fuel consumption ratio is 205-215 g/kW•h (153-160 g/HP•h) at rated flywheel horsepower. Lubricating oil refill capacity is 80-103 liters (21-27 US gal) depending on oil pan and installation. Cooling system capacity is not documented for this exact engine/truck combination in available public sources; verify with your dealer or the operation and maintenance manual for the confirmed serial range. Fuel tank capacity is not documented in available sources for this specific engine grouping; varies by configuration/series. Verify against the operation and maintenance manual for the confirmed serial range. Powershift transmission/torque converter capacity is not documented in available sources for this specific engine grouping; verify against the operation and maintenance manual for the confirmed serial range. Final drives capacity is not documented in available sources for this specific engine grouping; varies by configuration/series. Verify against the operation and maintenance manual for the confirmed serial range. Hydraulic system and tank capacity is not documented in available sources for this specific engine grouping; varies by configuration/series. Verify against the operation and maintenance manual for the confirmed serial range. Grease specification is Komatsu Genuine G2-LI multipurpose lithium EP grease. Engine oil specification is Komatsu Genuine EO diesel engine oil. Low-ash grades EO10W30-LA / EO15W40-LA for emissions-controlled builds, or EO10W30-DH / EO15W40-DH for earlier builds. Grade chosen by ambient temperature per the operation and maintenance manual viscosity chart. Coolant specification is Komatsu Super Coolant (AF-NAC or AF-ACL type), pre-mixed ethylene-glycol coolant with corrosion inhibitors, rated for cold-climate protection to roughly -36 degC (-33 degF). Concentration adjusted by climate per the operation and maintenance manual coolant chart. Fuel specification is ultra-low-sulfur diesel fuel meeting the SA12V140-1R engine's fuel specification; use winter-grade blend in cold climates per the operation and maintenance manual. Powertrain oil specification is Komatsu Genuine TO powertrain oil. TO10 (SAE 10W, API CD) for cold-climate service, TO30 (SAE 30W, API CD) for standard/warm-climate service. Axle/final-drive oil specification is Komatsu Genuine AXO axle/final-drive oil (AXO46 or AXO80, SAE 80W, API GL-4), grade selected by ambient temperature per the operation and maintenance manual chart. Hydraulic oil specification is Komatsu Genuine HO hydraulic oil. HO46-HM (ISO VG46) for standard/warm climates, HO56-HE (ISO VG56, SAE 5W-30 equivalent) for cold-climate service. Have your dealer verify fluid capacities and specifications for your exact serial range before service.

Machines equipped with the SA12V140-1R engine series, particularly heavy mining and construction haulers, operate in high-load environments that accelerate undercarriage wear. Track tension must be monitored regularly, as repeated loosening is a common issue linked to undercarriage wear and adjuster failure. Track-chain condition and roller condition should be inspected frequently, as mud or debris packed into the undercarriage can cause uneven wear and pulling to one side. Test travel symptoms in both forward and reverse to identify if a track consistently runs slower, which may indicate hydraulic or final-drive diagnosis rather than mechanical resistance. Final drive oil level and contamination should be checked regularly, as final drives making noise often indicate low oil or contamination. Frame rails and dump body hinge structure should be inspected for cracking, especially near hoist mounts. Have your dealer verify undercarriage wear limits and final drive inspection criteria for your specific machine model.

The SA12V140-1R series features a mechanical jerk-pump fuel injection system in many configurations, which lacks an electronic engine controller (ECM). This makes the engine straightforward to maintain and diagnose with gauges and visual inspection, but it is sensitive to fuel waxing and cold-start fuel quality in cold climates. The engine uses a Zexel PS7S mechanical governor, Komatsu high-pressure electrohydraulic control, or Bosch full-authority electronic control depending on the build/serial range. Exact system fitted varies by build/serial range. Verify the specific governor type against the shop manual for the serial range in question. The engine is water-cooled, turbocharged and aftercooled. It has a V-type 12-cylinder configuration. Displacement is 30.5 liters (30,480 cc). Bore is 140 mm. Stroke is 165 mm. Dry weight is approximately 3,100-3,300 kg depending on configuration. Flywheel horsepower ranges from 574 kW (770 HP) to 603 kW (808 HP) at 2,000 rpm depending on the specific application and governor type. Low idling speed ranges from 700 to 1,250 rpm depending on the application. Minimum fuel consumption ratio is 205-215 g/kW•h (153-160 g/HP•h) at rated flywheel horsepower. Lubricating oil refill capacity is 80-103 liters (21-27 US gal) depending on oil pan and installation. Cooling system capacity is not documented for this exact engine/truck combination in available public sources; verify with your dealer or the operation and maintenance manual for the confirmed serial range. Fuel tank capacity is not documented in available sources for this specific engine grouping; varies by configuration/series. Verify against the operation and maintenance manual for the confirmed serial range. Powershift transmission/torque converter capacity is not documented in available sources for this specific engine grouping; verify against the operation and maintenance manual for the confirmed serial range. Final drives capacity is not documented in available sources for this specific engine grouping; varies by configuration/series. Verify against the operation and maintenance manual for the confirmed serial range. Hydraulic system and tank capacity is not documented in available sources for this specific engine grouping; varies by configuration/series. Verify against the operation and maintenance manual for the confirmed serial range. Grease specification is Komatsu Genuine G2-LI multipurpose lithium EP grease. Engine oil specification is Komatsu Genuine EO diesel engine oil. Low-ash grades EO10W30-LA / EO15W40-LA for emissions-controlled builds, or EO10W30-DH / EO15W40-DH for earlier builds. Grade chosen by ambient temperature per the operation and maintenance manual viscosity chart. Coolant specification is Komatsu Super Coolant (AF-NAC or AF-ACL type), pre-mixed ethylene-glycol coolant with corrosion inhibitors, rated for cold-climate protection to roughly -36 degC (-33 degF). Concentration adjusted by climate per the operation and maintenance manual coolant chart. Fuel specification is ultra-low-sulfur diesel fuel meeting the SA12V140-1R engine's fuel specification; use winter-grade blend in cold climates per the operation and maintenance manual. Powertrain oil specification is Komatsu Genuine TO powertrain oil. TO10 (SAE 10W, API CD) for cold-climate service, TO30 (SAE 30W, API CD) for standard/warm-climate service. Axle/final-drive oil specification is Komatsu Genuine AXO axle/final-drive oil (AXO46 or AXO80, SAE 80W, API GL-4), grade selected by ambient temperature per the operation and maintenance manual chart. Hydraulic oil specification is Komatsu Genuine HO hydraulic oil. HO46-HM (ISO VG46) for standard/warm climates, HO56-HE (ISO VG56, SAE 5W-30 equivalent) for cold-climate service. Have your dealer verify fluid capacities and specifications for your exact serial range before service.

The SA12V140-1R series in many configurations uses a mechanical jerk-pump fuel injection system with no electronic engine controller (ECM), fault-code diagnostics, or sensor network. This mechanical simplicity means it is less prone to electronic sensor failures and unstable power supply issues that trigger multiple warning signals in later electronic models. However, if the specific build/serial range is equipped with Komatsu high-pressure electrohydraulic control or Bosch full-authority electronic control, electrical issues may arise. Verify the specific governor type against the shop manual for the serial range in question. For machines with electronic controls, intermittent starting, dashboard failure, or random shutdowns may indicate faulty sensors or unstable power supply. Engine performance issues such as loss of power, increased fuel usage, or overheating may signal airflow restriction, injector wear, or failing fuel delivery components. Check battery state of charge, battery terminals, engine and chassis grounds, main starter cable, starter relay and control circuit, and applicable safety or neutral-start inputs if the engine will not start. If the engine cranks but does not start, check fuel level and fuel quality, fuel filters, water separator, air entering the fuel supply, and engine fault codes. Have your dealer verify the electrical system configuration and diagnostic procedures for your exact serial range.

When buying a used machine with the SA12V140-1R engine (S/N 11640-UP), verify the exact serial-prefix specification sheet and installed attachment package. Confirm the exact governor type (Zexel PS7S mechanical, Komatsu electrohydraulic, or Bosch electronic) against the shop manual for the serial range in question, as this affects maintenance and diagnostics. Check the engine oil level on the dipstick and top up with Komatsu EO engine oil before start-up. Check coolant level in the sight glass and inspect for leaks around the SA12V140-1R block, radiator, and hoses. Drain water and sediment from the fuel tank sumps and check the fuel/water separator. Walk-around the frame, dump body hoist cylinders, and body pins looking for oil weeping or loose fasteners. Check tire condition and inflation on all positions and inspect rims for cracks. Test service brakes, park brake, and horn/backup alarm before moving the truck. Check hydraulic oil level, correct hydraulic oil specification, hydraulic filters, engine RPM under load, hydraulic oil temperature, and warning messages. Listen for unusual pump noise. If the machine is weak when hot, measure system performance cold and hot to diagnose internal leakage. Check track tension on both sides, roller condition, and track-chain condition. Inspect frame rails and dump body hinge structure for cracking, especially near hoist mounts. Torque-check dump body hoist cylinder pins and steering linkage fasteners. Check front and rear axle/differential oil level and condition. Inspect the turbocharger and aftercooler for oil seepage, boost leaks, and mounting security. Check the injection pump drive and fuel linkage for wear and correct travel. Have your dealer verify the exact serial range specifications, governor type, and fluid capacities before purchase.

Every 10 hours: Check engine oil level on the dipstick and top up with Komatsu EO engine oil before start-up. Check coolant level in the sight glass and inspect for leaks around the SA12V140-1R block, radiator, and hoses. Drain water and sediment from the fuel tank sumps and check the fuel/water separator. Walk-around the frame, dump body hoist cylinders, and body pins looking for oil weeping or loose fasteners. Check tire condition and inflation on all positions and inspect rims for cracks. Test service brakes, park brake, and horn/backup alarm before moving the truck (weekly 50 hours: grease steering and suspension pivot points). Every 250 hours: Change engine oil and oil filter using the specified Komatsu EO viscosity grade for ambient conditions. Grease all chassis, hoist, and articulation points with G2-LI grease per the lube chart. Service the engine air cleaner and check restriction indicator. Check powertrain (transmission/torque converter) oil level and top up with TO10 or TO30 as specified. Inspect brake cooling oil level and wet-disc brake wear indicators. Check wheel-rim nut torque and axle housing oil level. Every 500 hours: Replace primary and secondary fuel filters. Pull oil samples from engine, powertrain, and axle housings for fluid analysis before servicing. Replace hydraulic oil filter elements and inspect the hydraulic tank breather. Inspect the driveline U-joints, transmission mounts, and torque converter housing for leaks. Check frame rails and dump body hinge structure for cracking, especially near the hoist mounts. Torque-check dump body hoist cylinder pins and steering linkage fasteners. Every 1,000 hours: Change powertrain oil (TO10/TO30) and clean the transmission/torque converter suction screen. Check and adjust engine valve lash on the SA12V140-1R (mechanical jerk-pump engine, no electronic control). Inspect the turbocharger and aftercooler for oil seepage, boost leaks, and mounting security. Check front and rear axle/differential oil level and condition, top up with AXO46 or AXO80. Replace air cleaner primary and secondary elements. Inspect the injection pump drive and fuel linkage for wear and correct travel. Every 2,000 hours: Change hydraulic oil (HO46-HM or HO56-HE) and clean or replace the hydraulic tank strainer. Change front and rear axle/final drive oil and inspect final drive planetary sets for metal in the drain. Drain, flush, and refill engine coolant with Super Coolant AF-NAC or AF-ACL per the corrosion-inhibitor schedule. Inspect wet-disc brake packs, calipers, and cooling oil circuit for wear beyond service limits. Check steering cylinder, drag link, and kingpin wear. Inspect frame, dump body, and hoist cylinder mounts with dye penetrant or visual crack check. Every 6,000 hours: Evaluate the SA12V140-1R for a top-end or in-frame overhaul based on oil consumption, blow-by, and compression trends. Pull the torque converter and transmission for internal inspection or rebuild of clutch packs and bearings. Overhaul wet-disc brake assemblies and replace brake cooling oil circuit components as needed. Rebuild or replace front/rear axle housings, differentials, and final drive gearing as wear dictates. Inspect and, if required, rebuild the steering system pump, cylinders, and linkage. Have the frame and dump body structure inspected by a qualified welder and repaired before returning to service. Have your dealer verify maintenance intervals and procedures for your exact serial range.

If the engine overheats during heavy excavation, inspect the radiator, hydraulic oil cooler, charge-air cooler where fitted, air-conditioning condenser, and spaces between stacked coolers. Check coolant level when cold and fan operation. A machine may look clean from the outside while material is packed between heat exchangers. If temperature rises during heavy work but falls when the excavator is allowed to idle, cooling capacity may be marginal rather than completely absent. If coolant is repeatedly expelled or the system becomes highly pressurized shortly after a cold start, deeper engine diagnosis may be required. Have your dealer verify cooling system integrity and repair procedures for your exact serial range.