Komatsu S6D95L-1L(S/N 22170-UP)

The S6D95L-1 engine is a 6-cylinder inline diesel with a 95 mm bore and 115 mm stroke, displacing 4,890 cm³. Power output varies by application configuration: 82 HP at 2,150 rpm for earlier FD35/40Z-4 models, 85 HP at 2,150 rpm for FD35/40Z-5, 90 HP at 2,250 rpm for FD50/60/70-5, 95 HP at 2,250 rpm for FD50/60/70-6, and 110 HP at 2,000 rpm for the FD60H/70H/80H-5 configuration. Maximum torque ranges from 28 kgm (203 ft·lb) at 1,500 rpm for lower-output variants to 41.5 kgm (300 ft·lb) at 1,500 rpm for the highest-output FD60H variant. The engine uses a mechanical all-speed governor (Bosch RSV centrifugal type). Hydraulic systems paired with this engine typically exhibit slow performance when hot due to viscosity loss in internal pump or valve clearances; cold/hot performance comparison is required before diagnosing pump wear. Common hydraulic issues include weak swing or travel functions caused by pilot control faults, load-holding valve leakage, or final drive wear rather than main pump failure. Undercarriage wear patterns often manifest as track loosening or pulling to one side, requiring inspection of track tension, roller condition, and debris packing in the undercarriage before hydraulic diagnosis. The engine dry weight is 360 kg (794 lb) for the S6D95L-1 variant with a distributor pump, or 370 kg (816 lb) for the in-line pump version. Coolant capacity varies by configuration: 7.5 L (2.0 gal) for base models, 8.5 L (2.2 gal) for others, and up to 18 L (4.8 gal) for specific FD60H/70H/80H-5 applications. Lubricating oil capacity is 11 L (2.9 gal) for most variants, 13 L (3.4 gal) for FD35Z/40Z-5, and 12.5 L (3.3 gal) for FD60H/70H/80H-5. The engine requires Komatsu EO or equivalent heavy-duty diesel engine oil. The minimum fuel consumption ratio is consistently 160 g/HPh across all configurations. High idle speed is 2,350 ± 50 rpm for most variants, but 2,500 ± 50 rpm for FD50/60/70-5 and FD50/60/70-6, and 2,200 ± 50 rpm for FD35Z/40Z-5. Low idle is 700 ± 25 rpm for all. The firing order is 1-5-3-6-2-4. Overall dimensions vary slightly: length 983-986 mm (38.7-38.8 in), width 586-637 mm (23.1-25.1 in), height 809-876 mm (31.9-34.5 in) excluding exhaust. The alternator is 24 V, 15 A (or 25 A for FD35Z/40Z-5). Starting motor is 24 V, 4.5 kW (2.8 kW for some variants). Battery is 12 V, 70 Ah x 2. Turbocharger is Garrett 31 for FD60H/70H/80H-5. Fuel pump is Bosch type VE (distributor) or PE5 (in-line). Governor is Bosch RSV centrifugal mechanical all-speed type. Dry weight of cylinder head assembly is 41 kg (90 lb). Cylinder block assembly is 105 kg (232 lb). Crankshaft assembly is 35.5 kg (80 lb). Camshaft assembly is 8.5 kg (18.7 lb). Piston and connecting rod assembly is 2.1 kg (4.6 lb). Oil pump is 0.5 kg (1.1 lb). Fuel injection pump is 5.5 kg (12.1 lb). Water pump is 7.3 kg (16.1 lb) or 7.8 kg (17.2 lb) for 24V/25A alternator variant. Alternator weight is 4.0 kg (8.8 lb) for 24V/15A or 8.5 kg (18.7 lb) for 24V/4.5kW. Starting motor weight is 6.8 kg (15 lb) for 24V/2.8kW or 6.8 kg (15 lb) for 24V/4.5kW. Flywheel assembly is 17 kg (37 lb). Flywheel housing is 20 kg (44 lb) for 6D95L-1 or 35 kg (77 lb) for S6D95L-1. Timing gear case is 9.0 kg (20 lb) for FD50(E)-70(E) or 9.8 kg (22 lb) for others. Oil pan is 3.1 kg (6.8 lb). Turbocharger is 7.0 kg (15.4 lb) for S6D95L-1. Note: S6D95L-1 data applies to S6D95L-1L per source mapping. Variations in specs exist by configuration/series as noted above. Have your dealer verify exact specs for your serial range.

The S6D95L-1 series is prone to valve clearance drift and improper torque leading to bearing wear or head gasket issues. Precise torque on main bearings, rod bearings, head bolts, and rocker shaft is critical; incorrect torque can cause bearing failure or leaks. Valve clearance should be checked cold using feeler gauges; improper clearance leads to poor engine performance. The engine uses a mechanical all-speed governor (Bosch RSV centrifugal type) with Bosch type VE (distributor) or PE5 (in-line) fuel pumps. The firing order is 1-5-3-6-2-4. Overall dimensions vary slightly by configuration: length 983-986 mm (38.7-38.8 in), width 586-637 mm (23.1-25.1 in), height 809-876 mm (31.9-34.5 in) excluding exhaust. Dry weight is 360 kg (794 lb) for distributor pump variant, 370 kg (816 lb) for in-line pump variant. Coolant capacity varies: 7.5 L (2.0 gal), 8.5 L (2.2 gal), or 18 L (4.8 gal) depending on application. Lubricating oil capacity is 11 L (2.9 gal), 13 L (3.4 gal), or 12.5 L (3.3 gal) depending on application. The engine requires Komatsu EO or equivalent heavy-duty diesel engine oil. Minimum fuel consumption ratio is 160 g/HPh. High idle speed is 2,350 ± 50 rpm, 2,500 ± 50 rpm, or 2,200 ± 50 rpm depending on configuration. Low idle is 700 ± 25 rpm. Alternator is 24 V, 15 A or 25 A. Starting motor is 24 V, 4.5 kW or 2.8 kW. Battery is 12 V, 70 Ah x 2. Turbocharger is Garrett 31 for FD60H/70H/80H-5. Dry weight of cylinder head assembly is 41 kg (90 lb). Cylinder block assembly is 105 kg (232 lb). Crankshaft assembly is 35.5 kg (80 lb). Camshaft assembly is 8.5 kg (18.7 lb). Piston and connecting rod assembly is 2.1 kg (4.6 lb). Oil pump is 0.5 kg (1.1 lb). Fuel injection pump is 5.5 kg (12.1 lb). Water pump is 7.3 kg (16.1 lb) or 7.8 kg (17.2 lb). Alternator weight is 4.0 kg (8.8 lb) or 8.5 kg (18.7 lb). Starting motor weight is 6.8 kg (15 lb) or 6.8 kg (15 lb). Flywheel assembly is 17 kg (37 lb). Flywheel housing is 20 kg (44 lb) or 35 kg (77 lb). Timing gear case is 9.0 kg (20 lb) or 9.8 kg (22 lb). Oil pan is 3.1 kg (6.8 lb). Turbocharger is 7.0 kg (15.4 lb). Note: S6D95L-1 data applies to S6D95L-1L per source mapping. Variations in specs exist by configuration/series as noted above. Have your dealer verify exact specs for your serial range.

Komatsu excavators with this engine series rely heavily on electronic control systems. A single faulty sensor or unstable power supply can trigger multiple warning signals. Owners often report intermittent starting, dashboard failure, or machines that randomly shut down. Engine performance issues such as loss of power, increased fuel usage, or overheating may signal airflow restriction, injector wear, or failing fuel delivery components. For no-start conditions, check battery state of charge, battery terminals, engine and chassis grounds, main starter cable, starter relay, and control circuit. A battery can show acceptable voltage until the starter is loaded; perform a load and voltage-drop test before ordering a starter. If the engine cranks but does not start, check fuel level, fuel quality, fuel filters, water separator, air entering the fuel supply, and engine fault codes. If the machine stopped starting immediately after a filter replacement, check the work performed before assuming high-pressure component failure. The engine uses a 24 V electrical system with a 15 A or 25 A alternator and a 24 V, 4.5 kW (or 2.8 kW) starting motor. Battery is 12 V, 70 Ah x 2. Note: S6D95L-1 data applies to S6D95L-1L per source mapping. Variations in specs exist by configuration/series as noted above. Have your dealer verify exact specs for your serial range.

When buying a used machine with the S6D95L-1L engine, check for valve clearance drift and improper torque history leading to bearing wear or head gasket issues. Verify precise torque on main bearings, rod bearings, head bolts, and rocker shaft. Check valve clearance cold using feeler gauges. Inspect for signs of overheating: radiator, hydraulic oil cooler, charge-air cooler, air-conditioning condenser, and spaces between stacked coolers. Check coolant level when cold. Observe fan operation. Test engine performance under load to ensure it does not drop heavily in RPM when hydraulics are used. Check hydraulic oil level, correct specification, filters, and temperature. Inspect undercarriage for track loosening, roller condition, and track-chain condition. Check track tension on both sides. Look for mud or debris packed into the undercarriage. Test travel in both forward and reverse to check for pulling to one side. Inspect swing system for weakness or drift. Check for intermittent starting, dashboard failure, or random shutdowns indicating electrical issues. Verify battery state of charge, terminals, grounds, starter relay, and control circuit. Check fuel filters, water separator, and air entering the fuel supply. Note: S6D95L-1 data applies to S6D95L-1L per source mapping. Variations in specs exist by configuration/series as noted above. Have your dealer verify exact specs for your serial range.

Undercarriage wear patterns often manifest as track loosening or pulling to one side. This requires inspection of track tension, roller condition, and debris packing in the undercarriage before hydraulic diagnosis. Track tension should be checked on both sides. Mud or debris packed into one undercarriage can cause pulling. Roller condition and track-chain condition should be inspected. If the machine pulls to one side, test the symptom in both forward and reverse; if the same side remains weak in both directions, hydraulic or final-drive diagnosis becomes more relevant. Final drive makes noise if oil level and contamination are poor. Track repeatedly loosens due to tensioner or component wear. Note: S6D95L-1 data applies to S6D95L-1L per source mapping. Variations in specs exist by configuration/series as noted above. Have your dealer verify exact specs for your serial range.

Coolant capacity varies by configuration: 7.5 L (2.0 gal) for base models, 8.5 L (2.2 gal) for others, and up to 18 L (4.8 gal) for specific FD60H/70H/80H-5 applications. Lubricating oil capacity is 11 L (2.9 gal) for most variants, 13 L (3.4 gal) for FD35Z/40Z-5, and 12.5 L (3.3 gal) for FD60H/70H/80H-5. The engine requires Komatsu EO or equivalent heavy-duty diesel engine oil. The minimum fuel consumption ratio is consistently 160 g/HPh across all configurations. Note: S6D95L-1 data applies to S6D95L-1L per source mapping. Variations in specs exist by configuration/series as noted above. Have your dealer verify exact specs for your serial range.

If all hydraulic functions are slow, check hydraulic oil level, correct specification, filters, engine RPM under load, and oil temperature. Do not start by rebuilding one cylinder; shared hydraulic supply, pump control, engine performance, or pressure regulation deserves attention first. If one hydraulic function is slow but everything else works, investigate the affected circuit: cylinder leakage, control-valve spool operation, hose restriction or damage, load-holding valve, pilot control input, and mechanical binding. Compare the affected movement in both directions. If hydraulics work cold but become weak when hot, this indicates excessive internal leakage that becomes more noticeable at operating temperature due to decreased viscosity. Possible areas include hydraulic pump wear, main control valve leakage, hydraulic cylinder leakage, travel or swing motor leakage, and incorrect or degraded oil. Measure system performance cold and hot. Pressure and flow information is much stronger evidence than temperature behavior alone. If the excavator will not travel, determine whether the problem affects one track or both. If both tracks will not move, look for a shared issue such as hydraulic supply problem, pilot-control problem, travel control input, safety lock or interlock, electronic control fault. If only one track does not move, focus more closely on that travel motor, final drive, travel control valve circuit, hydraulic hoses, and mechanical track binding. If the excavator travels faster on one side or pulls sideways, check mechanical conditions first: track tension on both sides, mud or debris packed into one undercarriage, roller condition, track-chain condition, and whether both sides are in the same travel-speed mode. If the machine swings normally in one direction but poorly in the other, document the directional difference before components are replaced. If the upper structure drifts or will not hold position, check the swing brake and mechanical play. Note: S6D95L-1 data applies to S6D95L-1L per source mapping. Variations in specs exist by configuration/series as noted above. Have your dealer verify exact specs for your serial range.