Caterpillarexcavator

Caterpillar E650

Maintenance schedule, common problems & OEM parts breakdown

The Caterpillar E650 is a large mass-excavation and mining-class hydraulic excavator, built for Caterpillar in Japan under the Mitsubishi joint venture. Every documented unit runs the same powertrain: a Mitsubishi S6B-TA turbocharged inline-six diesel, 12.9 liters, rated at roughly 280 kW (375 hp) gross, with mechanical fuel injection and no electronic engine control. Operating weight runs from about 62.6 t (138,000 lb) in backhoe configuration up to 66 t (145,500 lb) as a loading shovel, the spread coming from front-end hardware and track shoe width. The E650 entered production in the 1980s as the largest member of Caterpillar's Japan-built E-series excavator family, offered as either a backhoe boom/stick digger or a face-loading shovel front for mining and quarry work.

Documentation on the E650 is thin compared with later Cat excavators, and only one serial prefix, 3KG, is confirmed in factory literature, pointing to a smaller production run than its lighter E-series siblings. The machine carries no electronic controls: diagnosis runs through analog gauges and warning lamps rather than fault codes, and every fluid and wear check is a manual, scheduled task rather than a system-flagged one. No confirmed direct successor model has surfaced in available documentation, so buyers should not assume a clean lineage into any later Cat mining shovel. In today's used and parts market the E650 survives mainly in quarry and mining fleets that value its mechanical simplicity and Mitsubishi engine commonality, with demand concentrated on undercarriage wear parts, engine rebuild components, and swing and travel drive hardware rather than complete used units.

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.

Caterpillar E650 specifications

Engine

Engine model	Mitsubishi S6B-TA, turbocharged inline-6 diesel (Cat-badged E650 chassis; the machine shares its powertrain and undercarriage parts with the Mitsubishi MS650)
Power rating	280 kW (375.5 hp) — this single figure is the only rating published; sources disagree on whether it is gross or net, so confirm the SAE basis with your dealer for the exact serial range
Displacement	12.9 L (786 cu in)
Cylinders	6, inline, turbocharged
Emissions tier	Not published. This is an older mechanical-injection design that predates modern nonroad emissions-tier certification — verify with your dealer for the specific unit

Weights

Operating weight	Approx. 62,600 kg (138,010 lb) to 66,000 kg (145,505 lb), varies by undercarriage/counterweight configuration
Ground pressure	Approx. 74.5-113.8 kPa (10.8-16.5 psi), varies by track shoe width and undercarriage configuration
Transport weight	Not separately published — treat the lower end of the operating-weight range as an approximation and confirm actual shipping breakdown with your dealer

Dimensions

Width over tracks	3.49 m (11.46 ft)
Height to top of cab	3.63 m (11.9 ft)
Undercarriage (track) length	5.42-5.43 m (17.79-17.8 ft)
Ground clearance	Approx. 0.67 m (26.4 in) per available spec data
Upper structure ground clearance	1.32-1.34 m (4.34-4.4 ft)
Tail swing radius / track shoe width	Not documented in available spec sources — confirm with dealer for the specific front/undercarriage configuration

Performance

Max dig depth	8.8-8.81 m (28.88-28.9 ft)
Max vertical wall dig depth	7.4-7.41 m (24.28-24.3 ft)
Max reach at ground level	13.33-13.35 m (43.74-43.8 ft)
Max dump height (mass-excavation/backhoe front)	8.36-8.38 m (27.43-27.5 ft)
Max cutting height (mass-excavation/backhoe front)	12.3-12.31 m (40.36-40.4 ft)
Max dig reach (loading-shovel front)	9.8 m (32.16 ft) — separate front-end configuration from the backhoe/mass-excavation dipper
Max dump height (loading-shovel front)	7.39 m (24.25 ft)
Max cutting height (loading-shovel front)	10.5 m (34.45 ft)
Stick length	3.47 m (11 ft 5 in)
Max travel speed	4.6-4.67 kph (2.86-2.9 mph)
Swing speed / gradeability / drawbar pull	Not documented in available spec sources for this model

Forces

Bucket digging force	Not published in available spec sources for this model — confirm with dealer or OEM spec sheet for the specific front configuration ordered
Stick/arm digging force	Not published in available spec sources for this model; no std-vs-long stick breakout was found

Service capacities (summary)

Fuel tank	625 L (165.2 gal)
Hydraulic system / hydraulic tank	Not documented in available spec sources
Engine oil	Not documented in available spec sources
Cooling system	Not documented in available spec sources

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

E650 fluids & capacities

System	Capacity	Recommended fluid
Engine crankcase (with filter)	Not documented in accessible sources for this exact configuration. The E650 (prefix 3KG) runs a Mitsubishi S6B-TA turbocharged inline-six; family engine literature for the S6B block cites a crankcase range near 40 L (10.6 US gal), but this figure is not confirmed against the E650 OMM itself — verify against the machine's own refill chart before servicing.	Cat Diesel Engine Oil (Cat DEO / DEO-ULS class), API CF or later. Select viscosity by ambient temperature per the standard Cat multigrade chart: heavier grade (SAE 15W-40) in temperate to warm climates, lighter grade (SAE 10W-30) where sustained cold starts occur below freezing.
Cooling system	Not documented in accessible sources for the E650.	Cat Extended Life Coolant (ELC) or Cat Diesel Engine Antifreeze/Coolant (DEAC), mixed per the coolant/glycol concentration chart in the OMM. Concentration is adjusted for ambient temperature range, not a fixed ratio.
Fuel tank	625 L (165.2 US gal)	Diesel fuel meeting Cat's standard distillate fuel specification. Use a low-sulfur or ultra-low-sulfur grade suited to the machine's emissions configuration and local climate (winter-blend in cold regions to control cloud point).
Hydraulic system total and hydraulic tank	Not documented in accessible sources for the E650.	Cat Hydraulic Oil (Cat HYDO Advanced or equivalent anti-wear hydraulic fluid), viscosity grade selected by ambient operating temperature per the OMM's climate chart.
Final drive (each)	Not documented in accessible sources for the E650.	Cat Transmission/Drivetrain Oil (Cat TDTO) gear oil, viscosity selected by climate.
Swing drive	Not documented in accessible sources for the E650.	Cat Transmission/Drivetrain Oil (Cat TDTO) gear oil, same class as final drive service, viscosity selected by climate.
Pilot/other circuits	Not listed as a separate serviceable circuit in accessible sources.	Not documented separately from the main hydraulic system for this model.
Grease (spec only)	Not applicable — grease points serviced by interval, not bulk refill.	Cat multipurpose or moly-fortified grease (NLGI 2), the standard chassis grease class used across Cat/Mitsubishi-built excavators of this era for pin and bushing points.

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

Caterpillar E650 maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level before starting and top off to the full mark on the S6B-TA Check coolant level at the header tank and inspect hoses, radiator, and fittings for leaks Drain water and sediment from the fuel/water separator Check hydraulic tank sight gauge and top off if the level is below the operating band Grease boom, stick, and bucket pivot pins per the lubrication chart, including the loading-shovel linkage when that front is fitted Walk around the undercarriage and check track tension, final drive seals, and swing bearing seals for leaks or looseness
Every 250 h	Change engine oil and replace the engine oil filter Replace primary and secondary fuel filters Check and adjust track shoe tension on both sides Grease the swing gear teeth and swing bearing race Inspect alternator, fan, and compressor drive belts and adjust tension or replace if cracked or glazed Check engine coolant condition and corrosion inhibitor concentration
Every 500 h	Replace the hydraulic tank return-line filter element Check final drive oil level in each travel motor housing and top off as needed Check swing drive housing oil level Pull oil samples from the engine, hydraulic system, and final drives for lab analysis Inspect the turbocharger for shaft play, boost-line leaks, and oil seepage past the seals Inspect batteries, terminals, and charging/starting wiring for corrosion and loose connections
Every 1,000 h	Change final drive (travel motor) housing oil in both final drives Change swing drive housing oil Replace hydraulic pilot and case-drain filter elements Re-torque track shoe bolts and sprocket segment bolts to spec Check swing bearing bolt torque and inspect for backlash or play Inspect fuel injection pump linkage and governor for wear or binding
Every 2,000 h	Change hydraulic tank oil, or extend the interval based on oil sample results Change engine coolant and flush the cooling system Inspect and adjust valve lash on the S6B-TA engine Inspect injectors and injection pump timing; send injectors for bench testing if power or smoke has changed Flow-test the main hydraulic pump, swing motor, and travel motors for internal wear Inspect boom, stick, and bucket (or shovel) pins and bushings for wear and replace as needed
Every 4,000 h	Pull the cylinder head for top-end inspection of valves, seats, and injector bores Inspect or rebuild the swing motor and travel motor assemblies as wear dictates Inspect the main hydraulic pump for internal wear or cracking and rebuild or exchange as needed Measure undercarriage components, sprockets, rollers, idlers, and track chain, against wear-limit charts and replace worn sets Inspect structural welds on the boom, stick, and mainframe for fatigue cracking

Servicing the E650 beyond the schedule

Predictive Maintenance & Fluid Analysis

The S6B-TA is a mechanical-injection diesel with no ECM, so there are no fault codes to trend. Condition monitoring has to run on scheduled oil sampling instead. Pull samples from the engine, hydraulic tank, swing drive, and each final drive on a fixed interval and watch for metal, water, or fuel dilution rather than waiting for a warning lamp. Log coolant condition and turbocharger shaft play by hand, since gauge readings and physical inspection are the only diagnostic tools this machine has.

Corrective & Common Repairs

Swing bearing and swing gear wear shows up first on machines run hard in mass-excavation duty, along with final drive seal leaks from continuous track loading. The turbocharger on the S6B-TA is a common wear point; watch for boost loss and oil seepage past the seals. Boom, stick, and bucket pins and bushings wear on both the backhoe and loading-shovel fronts and need regular greasing to slow it. Mechanical injection pumps and injectors lose calibration with hours and eventually need bench testing or reconditioning.

Overhaul & Rebuild Points

Plan top-end work on the S6B-TA around valve, injector, and turbocharger condition rather than a fixed hour number, since there is no ECM data to flag it early. Swing and travel motors, along with the main hydraulic pump, are the next major rebuild items on a machine this size. Undercarriage wear parts, including sprockets, rollers, idlers, and track chain, run through complete wear cycles under mining loads and should be measured against wear-limit charts. Inspect boom, stick, and mainframe welds for fatigue cracking at each major overhaul.

Seasonal & Environment Servicing

Quarry and mining sites push heavy dust into the S6B-TA's air intake and cooling package; check and clean the air filter and radiator fins more often in dry, dusty conditions. Abrasive fines pack into the swing bearing and undercarriage and accelerate wear if not cleaned out regularly. Cold starts on this mechanical diesel have no ECM-assisted cold-start strategy, so use starting aids and the correct-viscosity engine and hydraulic oil for the season. Adjust the coolant mix for the expected temperature range before seasonal extremes hit.

E650 attachments & work tools

Buckets

E650 operating weight runs about 62.6-66 t depending on backhoe vs loading-shovel configuration, putting it in the large mining-class excavator bracket. Factory bucket capacity figures for this specific model are not published in general spec catalogs. Buckets for this weight class are pin-on only — quick-coupler mounting is not the standard here — with heavy structural pins sized for mining/quarry shock loads. Expect GD and HD/rock bucket capacities in the low-to-mid single-digit cubic meter range typical of 60-70 t class machines; exact figures vary by configuration/series, so verify with your dealer for this model's bucket lineup.

Hydraulic hammers

This carrier's weight class (62.6-66 t) matches the Cat H180-class performance hammer, rated for 40,000-80,000 kg carriers, delivering roughly 14,900 J (11,000 ft-lbf) impact energy at 370-520 blows per minute — suited to primary rock production and continuous-shift quarry/demolition work. The lighter H140 (rated 25,000-40,000 kg carrier) sits below this excavator's class and would be undersized for sustained primary breaking on it.

Quick couplers

Heavy-duty hydraulic quick couplers rated up to roughly 70-85 t are offered by aftermarket coupler makers and would mechanically suit this weight class. In practice, production mining/quarry excavators this size are most commonly run with pin-on buckets only; coupler use is less common on dedicated production digging machines. Confirm coupler fitment and hydraulic provisions with your dealer before ordering one.

Thumbs/grapples

Hydraulic thumbs and grapples are not standard or well-documented work tools for this size of mining-class excavator — they are more typical on mid-size general construction/demolition machines. No model-specific documentation confirms compatible thumb or grapple kits for the E650; treat this as unconfirmed and check with your dealer.

Rippers

Rock ripper attachments (fixed tooth or hydraulic ripper tine on the stick or bucket) are used on large excavators in this weight class to pre-loosen hard or frozen ground, but no E650-specific ripper kit documentation was found. Ripper fitment for this model is unconfirmed.

Hydraulic-kit notes

An H180-class performance hammer needs roughly 220-300 L/min oil flow at about 16,000 kPa working pressure, which calls for a dedicated auxiliary high-flow circuit with its own control valve and return line. This is normally a factory- or dealer-installed hammer service kit rather than something the base digging circuit alone can support — confirm auxiliary hydraulics provisioning before ordering a hammer for this excavator.

All E650 assemblies by section

Every catalogued assembly group for the Caterpillar E650. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Engine

Accessory

Accessory Drive

After Cooler Piping

Air Compressor-Part 1 Of 2

Air Compressor-Part 2 Of 2

Air Compressor And Piping

Camshaft

Cooling System

Crankcase (Right Side And Upper)-Part 2 Of 2

Crankcase (Left Side And Front)-Part 1 Of 2

Crankcase Assy. And Main Bearing

Crankshaft And Flywheel

Cylinder Head

Dynamo

Dynamo General

Exhaust System

Fan Drive

Fuel Filter

Fuel Filter Piping

Fuel Injection Pump General

Fuel System

Inlet System

Oil Cooler

Oil Filter

Oil Filter And Breather

Oil Pan

Oil Pipe (For Turbocharger And Water Pump)

Oil Pump

Oil Strainer And Oil Pipe (For Inlet And Outlet)

Oil System (For Drive Case And Injection Pump)

Overhaul Gasket Kit

Oversize And Undersize

Piston And Connecting Rod

Rocker Cover

Starter

Stop System

Timing Gear

Timing Gear Case

Tools

Turbo Charger (Model Td10)

Valve Mechanism

Water Pump

Water Pump Assy.

Vehicle

Accumulator

Adjuster Cylinder

Air Cleaner-Part 1 Of 2

Air Cleaner-Part 2 Of 2

Air Conditioner-Part 1 Of 4

Air Conditioner-Part 2 Of 4

Air Conditioner-Part 4 Of 4

Air Conditioner-Part 3 Of 4

Air Conditioner Air Compressor

Air Conditioner Condenser

Air Conditioner Lines-Part 1 Of 2

Air Conditioner Lines-Part 2 Of 2

Air Conditioner Receiver

Air Lubricator

Air Supply Lines-Part 2 Of 2

Air Supply Lines-Part 1 Of 2

Am/Fm Radio

Arm And Bucket Lines-Part 1 Of 2

Arm And Bucket Lines-Part 2 Of 2

Arm Cylinder-Part 1 Of 2

Arm Cylinder-Part 2 Of 2

Base Frame

Boom And Accessories-Part 1 Of 2

Boom And Accessories-Part 2 Of 2

Boom Cylinder-Part 1 Of 2

Boom Cylinder-Part 2 Of 2

Boom Light And Harness

Boom Lines-Part 2 Of 2

Boom Lines-Part 1 Of 2

Boom Lubrication Lines

Bucket - Sae 2-3/8 Cubic Yards (Jis 1.6 Cubic Meters)

Bucket - Sae 3-7/8 Cubic Yards (Jis 2.6 Cubic Meters)

Bucket - Sae 2-7/8 Cubic Yards (Jis 1.9 Cubic Meters)

Bucket - Sae 3-3/8 Cubic Yards (Jis 2.3 Cubic Meters)

Bucket Cylinder-Part 1 Of 2

Bucket Cylinder-Part 2 Of 2

Bucket With Ripper - Sae 1-3/4 Cubic Yards (Jis 1.2 Cubic Meters)

Bucket With Ripper - Sae 2-1/4 Cubic Yards (Jis 1.5 Cubic Meters)

By - Pass Filter

Cab (Interior Parts)-Part 11 Of 12

Cab (Frame)-Part 2 Of 12

Cab (Window Washer)-Part 12 Of 12

Cab (Door And Window Frame)-Part 7 Of 12

Cab (Interior Parts)-Part 10 Of 12

Cab (Frame)-Part 1 Of 12

Cab (Door And Window Frame)-Part 5 Of 12

Cab (Door And Window Frame)-Part 6 Of 12

Cab (Glass And Corner Rubber)-Part 9 Of 12

Cab (Frame)-Part 3 Of 12

Cab (Frame)-Part 4 Of 12

Cab (Door And Window Frame)-Part 8 Of 12

Cab (Wiper Motor)

Cab Heater-Part 2 Of 2

Cab Heater-Part 1 Of 2

Carrier Roller

Catwalk

Check Valve

Control Valve A-Part 3 Of 3

Control Valve A-Part 2 Of 3

Control Valve A-Part 1 Of 3

Control Valve B-Part 3 Of 3

Control Valve B-Part 1 Of 3

Control Valve B-Part 2 Of 3

Counter Weight-Part 2 Of 2

Counter Weight-Part 1 Of 2

Counter Weight Lift Cylinder Lines-Part 3 Of 3

Counter Weight Lift Cylinder Lines-Part 2 Of 3

Counter Weight Lift Cylinder Lines-Part 1 Of 3

Cross Over Relief Valve-Part 2 Of 2

Cross Over Relief Valve-Part 1 Of 2

Delivery Lines-Part 2 Of 2

Delivery Lines-Part 1 Of 2

Pump Drive Gear-Part 2 Of 2

Drive Gear-Part 1 Of 2

Electric Parts-Part 1 Of 2

Electric Parts-Part 2 Of 2

Engine (For Winterized Version)-Part 2 Of 2

Engine-Part 1a Of 3

Engine-Part 2 Of 3

Engine (For Winterized Version)-Part 1 Of 2

Engine-Part 3a Of 3

Engine-Part 3 Of 3

Engine-Part 1 Of 3

Engine Control (For Automatic Engine Speed Control)-Part 2 Of 2

Engine Control

Engine Control (For Automatic Engine Speed Control)-Part 1 Of 2

Filter Regulator

Fire Wall

Front Guard

Front Lines-Part 2 Of 2

Front Lines-Part 1 Of 2

Fuel Feed System

Fuel Pump

Tank And Fuel Lines-Part 2 Of 2

Fuel Tank And Fuel Lines-Part 1 Of 2

Gear Pump

Grease Bath

Hand Rail And Side Mirror

Head Guard

Hose Reel

Hydraulic Tank-Part 2 Of 2

Hydraulic Tank-Part 1 Of 2

Idler Wheel

Link And Rod (For Medium Arm)

Lower Structure Cover

Main Pump-Part 2 Of 7

Main Pump-Part 3 Of 7

Main Pump-Part 7 Of 7

Main Pump-Part 6 Of 7

Main Pump-Part 1 Of 7

Main Pump-Part 5 Of 7

Main Pump-Part 4 Of 7

Medium Arm - 11'5" (3470mm)-Part 2 Of 2

Medium Arm - 11'5" (3470mm)-Part 1 Of 2

Medium Arm Lubrication Lines

Name Plate And Label (For Automatic Engine Speed Control)

Name Plate And Label (Body)-Part 1 Of 2

Name Plate And Label (Cab)-Part 2 Of 2

Over Head Guard

P.T.O. Valve

Pilot Filter

Pilot Relief Valve-Part 1 Of 2

Pilot Relief Valve-Part 2 Of 2

Pilot Valve

Pump Drive

Pump Suction Lines-Part 3 Of 3

Pump Suction Lines-Part 1 Of 3

Pump Suction Lines-Part 2 Of 3

Radiator

Radiator Baffle Plate-Part 1 Of 2

Radiator Baffle Plate-Part 2 Of 2

Radio Mantle

Remote Control Valve-Part 3 Of 3

Remote Control Valve-Part 1 Of 2

Remote Control Valve-Part 2 Of 2

Remote Control Valve-Part 1 Of 3

Remote Control Valve-Part 2 Of 3

Return Lines-Part 2 Of 2

Return Lines-Part 1 Of 2

Ripper

Rotary Joint

Seat And Floor Mat-Part 2 Of 2

Seat And Floor Mat-Part 1 Of 2

Seat Belt

Servo And Pilot Lines-Part 4 Of 6

Servo And Pilot Lines-Part 1 Of 6

Servo And Pilot Lines-Part 6a Of 6

Servo And Pilot Lines-Part 1a Of 6

Servo And Pilot Lines-Part 2 Of 6

Servo And Pilot Lines-Part 3a Of 6

Servo And Pilot Lines-Part 6 Of 6

Servo And Pilot Lines-Part 5 Of 6

Servo And Pilot Lines-Part 2a Of 6

Servo And Pilot Lines (For Automatic Engine Speed Control)-Part 2 Of 2

Servo And Pilot Lines-Part 4b Of 6

Servo And Pilot Lines-Part 4a Of 6

Servo And Pilot Lines-Part 3 Of 6

Servo And Pilot Lines (For Automatic Engine Speed Control)-Part 1 Of 2

Servo And Pilot Lines-Part 2b Of 6

Shut Off Valve

Shuttle Valve

Slow Return Valve

Solenoid Valve

Swing Bearing Lubrication Lines

Swing Control Valve-Part 1 Of 2

Swing Control Valve-Part 2 Of 2

Swing Drive-Part 1 Of 2

Swing Drive-Part 2 Of 2

Swing Frame

Swing Frame Cover (Side)-Part 2 Of 2

Swing Frame Cover (Side)-Part 1 Of 2

Swing Frame Cover (Support)

Swing Frame Cover (Under)

Swing Frame Cover (Upper)-Part 1 Of 2

Swing Frame Cover (Upper)-Part 2 Of 2

Swing Gear-Part 1 Of 2

Swing Gear-Part 2 Of 2

Swing Lock

Swing Motor-Part 1 Of 3

Swing Motor-Part 2 Of 3

Swing Motor-Part 3 Of 3

Swing Pump-Part 3 Of 7

Swing Pump-Part 2 Of 7

Swing Pump-Part 6 Of 7

Swing Pump-Part 4 Of 7

Swing Pump-Part 5 Of 7

Swing Pump-Part 7 Of 7

Swing Pump-Part 1 Of 7

Switch Box

Switch Box (Panel)-Part 1 Of 4

Switch Box (Rear)-Part 4 Of 4

Switch Box (Body)-Part 3 Of 4

Switch Box (Body)-Part 3b Of 4

Switch Box (Panel)-Part 1a Of 4

Switch Box (Body)-Part 3a Of 4

Switch Box (Meter Unit)-Part 2 Of 4

Tool Box

Tools

Track 24" (610mm) Triple Grouser Shoe

Track 30" (760mm) Triple Grouser Shoe

Track 35-7/8" (910mm) Triple Grouser Shoe

Track Guard

Track Roller

Travel Brake Valve

Travel Drive And Sprocket

Travel Gear-Part 3 Of 3

Travel Gear-Part 2 Of 3

Travel Gear-Part 1 Of 3

Travel Lines-Part 1 Of 2

Travel Lines-Part 2 Of 2

Travel Motor-Part 5 Of 6

Travel Motor-Part 4 Of 6

Travel Motor-Part 1 Of 6

Travel Motor-Part 6 Of 6

Travel Motor-Part 2 Of 6

Travel Motor-Part 3 Of 6

Travel Motor Lines-Part 2 Of 2

Travel Motor Lines-Part 1 Of 2

Traveling Control

Twin Clutch-Part 1 Of 2

Twin Clutch-Part 2 Of 2

Vandalism Guard

Water Separator

Winterized Version Parts

Wiring Harness-Part 1 Of 2

Wiring Harness-Part 2 Of 2

Working Control-Part 1 Of 2

Working Control-Part 2 Of 2

Yoke And Tension

E650 serial number reference

The PIN/serial plate is riveted to the machine frame, typically near the cab on the upper structure or main frame (pattern shared across Cat excavators of this era; confirm exact spot against the nameplate diagram in the parts book). Read the first three characters as the prefix, which ties the machine to its build series and engine fitment, then the following digits as the individual unit sequence number, e.g. 3KG00001.

Prefix	Identifies	Notes
3KG	Base E650 hydraulic excavator, Japan-built Cat E-series (Shin Caterpillar Mitsubishi)	Only documented prefix for the E650, covering 3KG00001 and up. Fitted with the Mitsubishi S6B-TA turbocharged inline-six diesel. Part of the Japan-built Cat E-series excavator line developed with Shin Caterpillar Mitsubishi; no separate long-undercarriage or letter-suffix variant tied to this prefix turned up in parts documentation.

Frequently asked questions

What engine powers the Caterpillar E650?

A Mitsubishi S6B-TA turbocharged inline-six diesel, 12.9 liters, rated at roughly 280 kW (375 hp) gross. It uses mechanical fuel injection with no electronic engine control, so there is no ECM or fault-code system on this machine.

What is the operating weight of the Caterpillar E650?

About 62.6 t (138,000 lb) in backhoe boom/stick configuration, rising to about 66 t (145,500 lb) as a loading shovel. Exact weight varies with front-end configuration and track shoe width.

What replaced the Caterpillar E650?

No confirmed direct successor model is documented for the E650. It was the largest machine in Caterpillar's Japan-built E-series excavator line; treat any claimed successor with caution and verify against a dealer or factory parts lookup for your specific serial number.

What E650 owners discuss

What do people who have actually run a Cat E650 say about its hydraulics and swing behavior?

This is a mechanical-era, open-center system predating load-sensing electronics, and the consensus is that it is simple and rugged but shows its age after decades of mining duty. Slow or weak swing under a loaded bucket is usually traced to a worn main pump or a tired swing-circuit relief/spool rather than any control module, since there isn't one to blame. Cylinder drift (boom or stick creeping down under load) is commonly chalked up to seal wear from age and heat cycling, not a design flaw. Any suspected internal leakage in a lift or swing circuit on a machine this size should have your dealer verify before you commit to a teardown.

What undercarriage wear pattern is typical for a machine in the E650's weight class?

At roughly 62.6-66 t operating weight, undercarriage wear is the single biggest lifetime cost driver on this class of excavator, commonly cited as accounting for a large share of total upkeep if neglected. Owners of similar mining-class machines report checking track tension routinely, since chains run too tight or too loose accelerate pin, bushing, and sprocket wear. Watch for shoe separation, flat-spotted rollers, and idler wobble as the classic tell-tale signs of a machine that has seen hard mining or quarry duty rather than light grading work.

What quirks come up around the Mitsubishi S6B-TA engine used in this machine?

The S6B-TA is a mechanically governed, turbocharged inline-six, and the general consensus on engines of this type and era is that injection timing is set manually at the pump and drifts out of spec after rebuilds or high hours, so rough running or excess smoke often traces back there rather than to the turbo itself. Cold-start smoke and a period of turbo lag before boost builds are considered normal for this generation of mechanical diesel. Clean fuel matters more than on later common-rail engines, since dirt or water in the system attacks the injection pump's precision components directly. Any injection timing or pump work should have your dealer or an authorized diesel shop verify the settings against factory spec.

Are there notable electrical or sensor issues to watch for?

Because this generation of machine predates ECM-based diagnostics, there is little in the way of sensor fault codes to chase, and that simplicity is generally seen as a plus for long-term ownership. What does show up after decades of service is corrosion at wiring harness connectors and ground points, along with gauge cluster readings that go erratic from a dirty or loose ground rather than a failed sender. Charging system and starter/solenoid faults are the other common age-related complaints, and both are usually resolved with basic continuity and voltage checks rather than a controller swap.

How available are parts and service support for this model today?

Given how few of these were built and how long ago, owners and shops generally report that parts sourcing takes patience. Engine components route through Mitsubishi industrial/heavy-equipment channels as much as through Cat dealer networks, and aftermarket overhaul kits for the S6B-TA exist because full engine rebuilds are a known part of keeping one of these running. Before buying or committing to a repair, confirm parts availability and lead time for the specific component in question rather than assuming dealer stock.

What fuel and hydraulic oil consumption should an owner expect?

As a large mining-class excavator, fuel burn under full digging load is materially higher than on a general construction excavator of similar size, which is consistent with what owners of comparable mechanical-era mining machines report. Because hydraulic cylinder and pump seals age out over decades of service, periodic hydraulic oil top-ups and closer-than-usual monitoring of reservoir levels are considered normal maintenance rather than a sign of a problem, provided there's no visible external leak.

What should a buyer check before purchasing a used E650?

Start by confirming the serial prefix matches this model's known 3KG range before trusting any paperwork or seller claims. Walk the undercarriage first, since remaining wear life drives resale value more than almost anything else on a machine this size — look for shoe separation, roller flat spots, and pin/bushing play. Run every cylinder to full travel and watch for drift, which points to internal seal leakage. Check the engine for smoke color and turbo spool-up behavior, and ask when the injection pump was last timed. Look closely at welds around the boom, stick, and mainframe for fresh paint hiding crack repairs. Because this is a low-production, long-out-of-production machine, also confirm with the seller and a parts source that key components are actually obtainable before you buy. Any structural weld repair or hydraulic cylinder reseal found during inspection should have your dealer verify before the machine goes back into service.

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

Need a specific E650 part?

Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.

Search parts in the app