Caterpillar 325B L
Caterpillarexcavator

Caterpillar 325B L

Maintenance schedule, common problems & OEM parts breakdown

Search live 325B L parts

The Caterpillar 325B L is a medium-class hydraulic excavator produced from 1998 to 2001. It is powered by the Cat 3116TA, a turbocharged and aftercooled inline-six diesel engine with 6.6 L displacement, rated at 168 hp net power. The machine operates in the 56,240 lb to 60,600 lb weight range depending on undercarriage configuration. It succeeded the first-generation 325/325 L/325 LN line and was followed by the 325C L family. Configurations include standard and long undercarriages with varying track shoe widths (600 mm to 800 mm) and multiple boom/stick options for reach or mass excavation.

The 325B L generation marked a shift in Caterpillar’s medium excavator lineup by introducing the Maestro Electronic Control System and refined hydraulic cross-sensing, while retaining the mechanically governed 3116TA engine. This mechanical simplicity, combined with robust X-shaped chassis design and heavy-duty undercarriage components, established the platform’s reputation for durability. In the used and parts market, the 325B L remains significant due to its ECM-free engine, which simplifies diagnostics and reduces dependency on complex electronic modules, making it a preferred choice for operators seeking reliable mid-size excavation with straightforward maintenance requirements.

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 325B L specifications

Engine

ModelCat 3116TA
Gross Power177 hp (132 kW)
Net Power168 hp (125 kW)
Displacement403 cu in (6,604 cu cm)
Cylinders6
Emissions TierNot documented for this exact serial range — verify with your dealer

Weights

Operating Weight (Standard Undercarriage)56,240 lb (25,510 kg)
Operating Weight (With 31.5 in Shoes)60,600 lb (27,488 kg)
Ground PressureNot documented for this exact serial range — verify with your dealer
Transport WeightNot documented for this exact serial range — verify with your dealer

Dimensions

Transport Length33.76 ft (10.29 m) with 20'2" boom / 31.86 ft (9.71 m) with 18'3" mass boom
Transport Width11.13 ft (3.39 m)
Transport Height10.73 ft (3.27 m) with 20'2" boom / 11.36 ft (3.46 m) with 18'3" mass boom
Tail Swing Radius10.01 ft (3.05 m)
Track Shoe Width31.5 in (80 cm) standard; 24 in, 28 in, 32 in optional
Ground Clearance1.68 ft (0.51 m)
Undercarriage Length (Track on Ground)12.46 ft (3.80 m)

Performance

Max Dig Depth23.27 ft (7.09 m) with 10'6" stick; 21.46 ft (6.54 m) with 8'8" stick; 19.72 ft (6.01 m) with 8'2" stick
Max Reach at Ground34.52 ft (10.52 m) with 10'6" stick; 32.85 ft (10.01 m) with 8'8" stick; 30.68 ft (9.35 m) with 8'2" stick
Max Dump Height23.33 ft (7.11 m) with 10'6" stick; 22.64 ft (6.90 m) with 8'8" stick; 20.02 ft (6.10 m) with 8'2" stick
Max Cutting Height32.68 ft (9.96 m) with 10'6" stick; 31.7 ft (9.66 m) with 8'8" stick; 29.96 ft (9.13 m) with 8'2" stick
Swing SpeedNot documented for this exact serial range — verify with your dealer
Travel Speed3.11 mph (5.00 km/h)
GradeabilityNot documented for this exact serial range — verify with your dealer
Drawbar Pull48,333.92 lb (21,475 kg)

Forces

Bucket Digging ForceNot documented for this exact serial range — verify with your dealer
Stick/Arm Digging ForceNot documented for this exact serial range — verify with your dealer

Service capacities (summary)

Fuel Tank111 gal (420 L)
Hydraulic System/Tank81.9 gal (310 L)
Engine Oil5.3 gal (20 L)
Cooling System8.4 gal (32 L)

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

325B L fluids & capacities

SystemCapacityRecommended fluid
Engine crankcase (with filter)20 L (5.3 US gal)Cat DEO (Diesel Engine Oil). SAE 10W-30 for ambient -18 to 40°C (0 to 104°F); SAE 15W-40 for -9 to 50°C (15 to 122°F).
Cooling system31.5 L (8.3 US gal)Cat DEAC (Diesel Engine Antifreeze/Coolant), ethylene glycol base, mixed 50/50 with clean water for freeze protection to about -37°C (-34°F). Cat ELC accepted as a full-life alternative.
Fuel tank420 L (111 US gal)No. 1-D or No. 2-D diesel fuel per ASTM D975. Switch to a winter-grade blend or add a cold-flow additive in freezing climates to prevent fuel waxing.
Hydraulic system total AND hydraulic tank310 L (82 US gal)Cat HYDO anti-wear hydraulic oil. Standard grade suits roughly -20 to 40°C (-4 to 104°F) ambient; ask the dealer about an arctic or high-ambient grade outside that band.
Final drive (each)8 L (2.1 US gal)Cat TDTO (Transmission/Drive Train Oil), TO-4 spec. SAE 30 for normal climates, SAE 10W for cold-weather work, SAE 50 for sustained hot climates.
Swing drive10 L (2.6 US gal)Cat TDTO, TO-4 spec, same grade selection by ambient temperature as the final drives.
Pilot/other circuitsNot separately documented; the pilot circuit draws off the main hydraulic reservoir and has no standalone refill figureSame Cat HYDO hydraulic oil as the main hydraulic system.
Grease (spec only)No refill volume published; lubricated at individual grease fittings on pins, bushings, and the swing bearingCat Multipurpose Grease, NLGI Grade 2, for general pin and bushing points. Cat Advanced 3Moly Grease for extreme-pressure/high-load points such as the swing gear and bucket linkage where specified.

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

Caterpillar 325B L maintenance schedule

Service intervalTasks
Every 10 h
  • Check engine oil, coolant, and hydraulic oil levels before starting the machine.
  • Drain water and sediment from the fuel/water separator.
  • Walk down the undercarriage and check track shoe, roller, and idler condition.
  • Grease boom, stick, and bucket linkage pins.
  • Check swing drive oil level and look for water intrusion or discoloration.
  • Scan the cab monitoring panel gauges for abnormal readings.
Every 250 h
  • Change engine oil and filter.
  • Replace the fuel filter and inspect the fuel system for water contamination.
  • Pull an engine oil sample for analysis.
  • Check final drive oil level.
  • Inspect and adjust track sag on the undercarriage.
Every 500 h
  • Change the hydraulic oil filter.
  • Change swing drive oil and inspect for contamination from swing brake seal leakage.
  • Sample hydraulic oil for wear metals and particulate contamination.
  • Check alternator belt tension and condition.
  • Inspect the turbocharger for shaft play and oil seepage.
  • Check engine coolant condition and top off coolant additive.
Every 1,000 h
  • Change final drive oil.
  • Replace air filter elements.
  • Inspect and adjust governor linkage for sluggish throttle response.
  • Check swing bearing and gear lubrication.
  • Inspect injector tip O-rings for leakage or fuel dilution of engine oil.
  • Check oil cooler O-rings for seepage.
Every 2,000 h
  • Change hydraulic tank oil.
  • Replace the hydraulic oil filter.
  • Check swing gear and pinion backlash.
  • Adjust engine valve lash on the 3116TA.
  • Flush and refill the engine cooling system.
  • Inspect swing brake seals for wear or leakage into the swing drive.
Every 4,000 h
  • Inspect turbocharger and injectors for wear trends flagged by oil analysis.
  • Evaluate the swing drive and brake assembly for rebuild based on contamination history.
  • Inspect the hydraulic pump and main control valve for wear from long-term contamination.
  • Assess undercarriage rollers, idlers, and shoes for rebuild.
Every 6,000 h
  • Perform a top-end engine overhaul on the 3116TA: injectors, turbocharger, and cylinder head as required.
  • Rebuild the swing drive and brake assembly.
  • Rebuild or replace undercarriage components: shoes, rollers, idlers, and sprockets.
  • Overhaul the hydraulic pump and valve bank.

Servicing the 325B L beyond the schedule

Predictive Maintenance & Fluid Analysis

The 325B L lacks an engine ECM, making fluid analysis critical for early fault detection. Pull engine oil samples at every 250-hour interval to monitor wear metals from the mechanical injection pump and turbo bearings. Inspect swing drive oil for water intrusion or friction material, indicating swing brake seal leakage. Sample hydraulic oil for particulate contamination, which causes valve sticking and cavitation in the cross-sensing system. Use the cab monitoring panel gauges for real-time temperature and pressure checks, as stored fault codes are not available for the 3116TA engine.

Corrective & Common Repairs

Common repairs on the 325B L focus on the 3116TA’s mechanical wear points. Replace oil cooler O-rings when coolant or oil levels drop unexpectedly due to seepage. Address injector tip O-ring failure, which causes fuel dilution and rough running, by replacing them as a set. Correct sluggish throttle response by inspecting and adjusting the governor linkage, as this is a mechanical system prone to bushing wear. Fix swing drive contamination by replacing brake seals to prevent oil migration from the swing brake into the drive assembly.

Overhaul & Rebuild Points

Major rebuild intervals for the 325B L align with the 3116TA’s mechanical top end and hydraulic systems. Perform top-end engine overhaul at 6,000 hours, including injector, turbocharger, and cylinder head work, triggered by fuel dilution or blow-by trends in oil analysis. Rebuild the swing drive and brake assembly together, as failed seals accelerate gear wear. Replace undercarriage components—shoes, rollers, idlers, and sprockets—at 6,000 hours or earlier if operating on sidehill grades. Overhaul the hydraulic pump and valve bank to address long-term contamination wear.

Seasonal & Environment Servicing

Cold-weather operation for the 325B L requires ether-assist and coolant heater use below freezing, as the mechanically governed 3116TA lacks ECM-managed cold-start aids. Use SAE 10W-30 engine oil for ambient temperatures between -18°C and 40°C, switching to SAE 15W-40 for -9°C to 50°C. In dusty environments, clean radiator fins daily and replace air filter elements at 500 hours instead of 1,000 hours. Use No. 1-D or No. 2-D diesel with cold-flow additives in freezing climates to prevent fuel waxing, and verify coolant freeze protection to -37°C using Cat DEAC mixed 50/50 with clean water.

325B L fault codes & troubleshooting

CodeMeaningLikely causeWhat to do
CID 0110 FMI 03Engine Coolant Temperature Sensor — Voltage Above NormalOpen circuit in the sensor wiring harness or a failed sensor element causing a short to the power supply.Inspect the sensor wiring for damage or disconnection; test sensor resistance and replace if the circuit is intact but the sensor is faulty.
CID 0190 FMI 08Engine Speed Sensor — Abnormal Frequency, Pulse Width, or PeriodIncorrect air gap between the sensor and the tone ring, a damaged tone ring, or a failing sensor.Check the sensor mounting and air gap; inspect the tone ring for physical damage or debris; test the sensor output signal.
CID 0041 FMI 038-Volt DC Supply — Voltage Above NormalShort to power on the 8-volt reference circuit shared by multiple sensors.Disconnect sensors on the 8-volt reference circuit one by one to isolate the shorted component or wiring segment.
CID 0041 FMI 048-Volt DC Supply — Voltage Below NormalShort to ground on the 8-volt reference circuit.Disconnect sensors on the 8-volt reference circuit one by one to locate the component causing the ground fault.
CID 0262 FMI 045-Volt Supply — Voltage Below NormalShort to ground on the 5-volt reference circuit used by electronic sensors.Isolate the short by disconnecting sensors on the 5-volt circuit sequentially until the voltage returns to normal.
CID 0248 FMI 09CAT Data Link — Abnormal Update RateCommunication fault on the data link, often caused by damaged wiring, poor connections, or a termination resistor issue.Inspect the data link connectors for corrosion or damage; measure termination resistance; check for wiring chafing or shorts.
CID 0168 FMI 04System Voltage — Voltage Below NormalLow battery voltage, failing alternator/generator, or excessive parasitic drain.Check battery charge and terminal connections; test generator output under load; inspect wiring for high resistance.
CID 0091 FMI 02Throttle Position Sensor — Erratic, Intermittent, or IncorrectFaulty throttle sensor, loose wiring connector, or intermittent signal loss.Check the throttle sensor connector for tightness and corrosion; monitor live data for signal jumps; replace sensor if wiring is good.
CID 0268 FMI 02Programmed Parameter Fault — Erratic, Intermittent, or IncorrectECM memory corruption, low system voltage during programming, or a failed ECM.Check system voltage stability; attempt to reprogram the ECM using diagnostic software; replace ECM if faults persist.
CID 0325 FMI 07Fuel Pressure Regulator — Mechanical System Not Responding ProperlyStuck regulator valve, clogged fuel filter, or mechanical failure in the fuel system.Check fuel filter condition and fuel pressure; inspect the regulator for mechanical binding; replace regulator if necessary.

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

325B L attachments & work tools

Buckets

Reference capacity ranges from 1.5 to 2 cubic yards (1.1 to 1.5 cubic meters), with minimums of 1.4 cubic yards (1.1 cubic meters) and maximums up to 3 cubic yards (2 cubic meters) depending on the specific boom and stick configuration selected.

Buckets

Pin diameters are not explicitly documented in the provided specifications; however, the machine utilizes standard bucket link assemblies compatible with the 325 series family, requiring verification of the specific link part number for exact pin sizing.

Hydraulic hammers

The machine supports auxiliary hydraulic tools via an optional Auxiliary Hydraulic Flow Control System that provides up to four programmable flow presets to match breaker requirements.

Hydraulic hammers

Main implement system maximum flow is 56.5 gallons per minute (214 liters per minute) across two circuits, which dictates the compatible class of hydraulic hammer for this medium excavator size.

Quick couplers

The 325B L is compatible with standard excavator quick coupler systems; specific pin dimensions and hydraulic hose routing must be verified against the selected coupler manufacturer's guide for this weight class.

Thumbs/grapples

The machine supports optional thumb kits and grapple attachments; fitment depends on the specific boom and stick option installed, requiring consultation with the dealer for the correct mounting hardware.

Rippers

Ripper attachments are available as part of the wide selection of buckets and attachments; compatibility is determined by the specific boom and stick combination chosen for the machine.

Hydraulic-kit notes

The standard hydraulic system relief valve pressure is 4974.8 psi (34300 kPa), and the pilot system maximum pressure is 595 psi (4100 kPa).

Hydraulic-kit notes

The Auxiliary Hydraulic Flow Control System option is required for precise matching of hydraulic tool requirements such as hammers, shears, processors, and brush cutters.

All 325B L assemblies by section

Every catalogued assembly group for the Caterpillar 325B L. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Electrical And Starting System
1882647 Wiring Gp
18***47Wiring Group-Generator1
See all parts with full part numbers in Heavy Parts AI →
Frame And Body
1908272 Installation Arrangement
19***72Installation Arrangement1
See all parts with full part numbers in Heavy Parts AI →
Hydraulic System
9t1817 Filter Group
9T***17Filter Group; (O) (Bsc)1
See all parts with full part numbers in Heavy Parts AI →
1908269 Generator Ar
19***69Generator Ar1
19***70Generator Arrangement1
19***72Installation Arrangement1
See all parts with full part numbers in Heavy Parts AI →
1908270 Generator Arrangement-Hydraulic
18***46Lines Group-Hydraulic1
18***47Wiring Group-Generator1
19***70Generator Arrangement1
See all parts with full part numbers in Heavy Parts AI →
1882646 Lines Gp-Hydraulic
18***46Lines Group-Hydraulic1
See all parts with full part numbers in Heavy Parts AI →
Service Equipment And Supplies
2019908 Film-Enclosure
20***08Film; (Generator Enclosure)(Enclosure)1
See all parts with full part numbers in Heavy Parts AI →

325B L serial number reference

Locate the durable metal identification plate riveted to the main frame, typically on the right-hand side below the cab or near the boom base. The Product Identification Number (PIN) consists of a 3-character alphanumeric prefix followed by a 5-digit sequence ID.

PrefixIdentifies
1YS325B L
2JR325B L

Frequently asked questions

What engine does the Caterpillar 325B L use?

The Caterpillar 325B L uses the Cat 3116TA, a turbocharged and aftercooled inline-six diesel engine with 6.6 L displacement, rated at 168 hp net power.

What is the operating weight of the Caterpillar 325B L?

The operating weight varies by configuration: 56,240 lb (25,510 kg) for the standard undercarriage and 60,600 lb (27,488 kg) for the long undercarriage.

What model replaced the Caterpillar 325B L?

The 325B L was succeeded by the 325C L family, which introduced electronic engine control with the C9 engine.

What 325B L owners discuss

What is the engine configuration and power rating for the Caterpillar 325B L?
The machine uses a Cat 3116TA turbocharged and aftercooled inline-six diesel engine. Net power is 125 kW (168 hp) at 2000 rpm. Gross power is 132 kW (177 hp). The engine is mechanically governed with no electronic control module (ECM). Displacement is 6.6 L (403 cu in). Bore is 105 mm (4.13 in). Stroke is 127 mm (5 in). Fuel system is mechanical injection without CID/FMI fault codes. Diagnosis relies on the cab monitoring panel gauges and oil analysis rather than stored electronic codes. Governor linkage wear can cause sluggish throttle response. Injector tip O-rings and oil cooler O-rings are common wear points that lead to fuel dilution or coolant/oil seepage. Cold starts below freezing benefit from ether assist and coolant heaters due to the lack of ECM-managed cold-start aids. Verify exact emissions certification tier against the engine serial number with a dealer, as the machine was built during the 1998-2001 production run without factory aftertreatment.
How does the hydraulic system behave, and what are the common hydraulic issues?
The hydraulic system features a cross-sensing design that improves implement speeds and pivot turns. It includes a boom regeneration circuit to lower the boom using cylinder oil, freeing pump flow for other circuits. Maximum pressure is 34,300 kPa (4980 psi) for equipment and travel, and 29,400 kPa (4250 psi) for swing. Main implement system maximum flow is 214 L/min (56.5 gpm) per pump. Pilot system maximum flow is 41 L/min (10.8 gpm). The system uses Cat HYDO anti-wear hydraulic oil. Common issues include valve sticking and cavitation driven by hydraulic contamination. Swing brake seal failures allow oil to migrate into the swing drive, contaminating the drive oil and accelerating gear wear. Auxiliary hydraulic flow control system options provide up to four programmable flow presets. The machine lacks the factory high-flow/tiltrotator plumbing of later generations; hammer and grapple work relies on conventional medium-pressure auxiliary lines. Hammer flow should match roughly 60-80% of the machine's available implement flow. One-way plumbing suits hammers; two-way plumbing is required for thumbs, grapples, and compaction plates.
What are the typical undercarriage wear patterns and specifications for the 325B L?
The 325B L uses a long undercarriage configuration to maximize stability and lifting capacity. Standard track shoe width is 800 mm (32 in). Track gauge is 3 m (9.8 ft). Ground clearance is 0.48-0.49 m (1.58-1.6 ft). Track-on-ground length is 3.80-3.81 m (12.47-12.5 ft). The undercarriage components are oversized for heavy-duty performance. Strutted track links are sealed. Travel motors offer a two-speed auto-shifting design. Final drive oil capacity is 8 L (2.1 US gal) per side. Swing drive oil capacity is 10 L (2.6 US gal). Common undercarriage issues include uneven wear on sidehill grades. Debris packed around the drive motors can force the floating face seal out of place, leading to gear oil leaks and contamination. The undercarriage should be cleaned at the end of each shift to prevent debris from wedging between the seal faces. Track sag should be inspected and adjusted regularly. The 325B L is distinct from the 325B LN, which uses a narrower gauge (2.39-2.41 m) and 600 mm shoes for confined-site work, resulting in faster undercarriage wear on uneven ground.
What are the common electrical or sensor-related issues given the machine's age and design?
The Caterpillar 325B L does not have an engine ECM or electronic engine control. Electronic engine control arrived with the subsequent 325C L family. The machine relies on a mechanical governor and cab monitoring panel gauges for diagnostics. There are no CID/FMI fault codes associated with the engine. The Electronic Power Unit Control System manages hydraulic and engine performance but does not provide stored fault codes for the engine. Operators must rely on gauge readings and oil analysis for engine health. The alternator supplies 52 amps at 24 volts. The operator control panel includes gauges for fuel level, hydraulic oil temperature, and engine temperature. Loss of power to the cab can occur but is not linked to a specific electronic fault code due to the lack of an ECM. Calibration of the governor may require running calibration steps multiple times through the monitor panel, though Caterpillar ET may be needed in some cases if the monitor panel cannot complete the process. Verify connectivity with diagnostic tools with a dealer, as older serial ranges may have varying interface capabilities.
What should be checked when buying a used 325B L?
Check the engine oil for fuel dilution, which indicates worn injector tip O-rings. Inspect the oil cooler for seepage by checking coolant and oil levels. Verify governor linkage operation for sluggish throttle response. Inspect the swing drive oil for water intrusion or discoloration, which signals swing brake seal leakage. Check the floating face seal on the final drive motors for gear oil leaks between the sprocket and the motor. Inspect the undercarriage for uneven wear, especially if the machine has been used on sidehill grades. Verify the track shoe width and gauge match the 325B L specifications (800 mm shoes, 3 m gauge). Check the hydraulic system for contamination by sampling the hydraulic oil. Inspect the swing bearing and gear lubrication. Verify the exact serial prefix against the factory spec sheet to confirm the installed boom/stick combination and undercarriage configuration. Confirm the emissions certification tier against the engine serial number. Have your dealer verify the swing drive and brake assembly condition based on contamination history.

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

Need a specific 325B L part?

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

Search parts in the app