0445120125
BOSCH 0445120125 Common Rail Injector for Komatsu PC300-8 & Cummins QSL9 8.9L
6745113102, 6745-11-3102, 6745123100, 6745-12-3100, 3965721, 3973060, 4939061, 4940170, 5263308, 84346812F00RJ01941DLLA118P16971600 barProduct Overview
The Bosch 0445120125 is a heavy-duty CRIN2-16 common rail diesel fuel injector engineered for Komatsu PC300-8 and PC350-8 crawler excavators, WA380-6 wheel loaders, Case CX350B excavators, and industrial machinery powered by the Komatsu SAA6D114E-3 and Cummins QSL9 8.9L 6-cylinder turbocharged diesel engines (250 to 400 hp / 187 to 298 kW). Engineered for peak injection pressures up to 1600 bar, this solenoid-operated injector incorporates control valve assembly F00RJ01941, hole-type nozzle 0433172040 (stamped DLLA118P1697), magnet assembly F00RJ02697, and seal ring kit F00RJ02176. It meets Tier 3 and Stage IIIA off-highway emissions standards and is fully interchangeable with Komatsu OE part numbers 6745-11-3102 and 6745-12-3100, Cummins OE numbers 3965721, 4940170, and 5263308, Case OE 84346812, and Bosch remanufactured codes 0986435522 and 0986435560.
Vehicle & Engine Fitment
| Vehicle | Engine | Years |
|---|---|---|
| Komatsu PC300-8 / PC300LC-8 Heavy Crawler Excavator | Cummins QSL9 / ISLe 8.9L & Komatsu SAA6D114E-3 (8.9L) | 2006-2018 |
| Komatsu PC350-8 / PC350LC-8 Heavy Crawler Excavator | Cummins QSL9 / ISLe 8.9L & Komatsu SAA6D114E-3 (8.9L) | 2006-2018 |
| Komatsu WA380-6 / WA430-6 Wheel Loader | Cummins QSL9 / ISLe 8.9L & Komatsu SAA6D114E-3 (8.9L) | 2006-2018 |
| Case CX290B / CX350B / CX370B Heavy Excavator | Cummins QSL9 / ISLe 8.9L & Komatsu SAA6D114E-3 (8.9L) | 2007-2017 |
| Cummins QSL9 Industrial & Construction Power Unit | Cummins QSL9 / ISLe 8.9L & Komatsu SAA6D114E-3 (8.9L) | 2006-2018 |
Technical Specifications
| Specification | Value |
|---|---|
| SKU | 0445120125 |
| Manufacturer | BOSCH |
| System Type | Common Rail Injector (CRIN2-16) |
| Nozzle CodeCore Spec | |
| Control ValveCore Spec | |
| Magnet Assembly | F00RJ02697 |
| Seal Ring Kit | F00RJ02176 |
| Peak Pressure | 1600 bar |
| Emission Standard | Tier 3 / Stage IIIA |
| Hold-Down Clamp Torque | 24-30 N·m📐 Torque & Angle Wizard → |
| Feed Tube Torque | 15 N·m pre-torque / 50-55 N·m final |
| High-Pressure Line Torque | 30-35 N·m (two-wrench method) |
| IMA Coding Required | No (Self-adapting via Komatsu / Cummins ECU) |
| Solenoid Resistance | 0.25 - 0.50 Ohm at 20°C |
| Operating PressureCore Spec |
Installation Tips
Tools needed: Calibrated torque wrench and line crowfoot tool, Brass injector bore seat brush kit and industrial vacuum extraction unit, Dedicated electronic diagnostic tool for IMA/injector coding
- Thoroughly clean the injector bore in the cylinder head using a dedicated brass brush and vacuum cleaner, ensuring complete removal of carbon deposits and debris.
- Install a new genuine copper sealing washer (1.5 mm thickness) onto the nozzle tip and lubricate the body O-ring with clean engine oil.
- Lower the 0445120125 injector into the cylinder bore, carefully aligning the lateral fuel inlet port with the cylinder head connector tube port.
- Insert the high-pressure connector tube (feed tube) through the cylinder head port until its spherical nose seats into the injector inlet cup; pre-tighten the retaining nut to 15 N·m.
- Install the injector hold-down clamp and torque the clamp bolt to its final specification of 24-30 N·m.
- Torque the connector tube retaining nut to its final specification of 50-55 N·m to establish a metal-to-metal high-pressure seal.
- Connect the high-pressure fuel supply jumper line using the two-wrench technique, torque the union nut to 30-35 N·m, and prime the fuel circuit before initial engine start.
- Never torque the hold-down clamp before the feed tube is aligned and pre-torqued. Doing so shears the spherical sealing face and causes high-pressure backleakage into the crankcase.
- Always inspect the spherical sealing tip and edge-filter of the feed tube for scoring, erosion, or fretting; replace the feed tube if any wear is visible.
- Always use a second wrench to support the connector tube fitting when torquing the fuel rail jumper line to 30-35 N·m, preventing rotation that cracks the cylinder head boss.
Frequently Asked Questions
What symptoms indicate failure of a Bosch 0445120125 injector in a Komatsu PC300-8 excavator?
Common symptoms include excessive dynamic backleakage caused by control valve F00RJ01941 seat erosion, extended engine cranking, hard starting when hot, black or grey exhaust smoke under hydraulic load, loss of engine power, and diagnostic trouble code P0087 (Rail Pressure Too Low).
Does the 0445120125 injector require an IMA coding procedure in the Komatsu ECU?
No. The early CRIN2 platform does not require IMA (Injector Quantity Adjustment) code programming. The Komatsu / Cummins electronic control unit utilizes closed-loop cylinder balancing and crankshaft acceleration feedback to calibrate fuel delivery trims automatically.
What OEM part numbers correspond to Bosch 0445120125?
Official Komatsu OE cross-references include 6745-11-3102 (6745113102) and 6745-12-3100 (6745123100). Cummins OE references include 3965721, 3973060, 4939061, 4940170, and 5263308. Case OE reference is 84346812. Bosch exchange codes include 0986435522 and 0986435560.
What is the acceptable dynamic backleak return flow limit on a test bench?
At full-load test bench conditions (1600 bar rail pressure), return fuel flow should not exceed 45 ml/min per injector. Dynamic return flow exceeding 50 ml/min indicates internal valve seat cavitation requiring replacement of control valve F00RJ01941.
What is the correct electrical resistance for the solenoid actuator coil?
Measured across the injector terminals at 20°C, the solenoid coil resistance must be between 0.25 and 0.50 Ohm. Resistance values outside this specification indicate shorted or open windings and trigger diagnostic fault codes P0201 through P0206.
Diagnostic Trouble Codes & Fault Protocols
Common diagnostic trouble codes (DTCs) triggered when this common rail injector experiences wear, circuit faults, or calibration drift:
Fuel Rail / System Pressure Too Low
Excessive internal backleak from worn control valve seats drops common rail pressure below target under engine load.
Injector Circuit Malfunction / Open Circuit
Solenoid coil resistance drift (0.2-0.5 Ω) or piezo stack degradation triggers driver stage shutdown on affected cylinders.
Cylinder Misfire & Balancing Deviation
Carbon-clogged nozzle spray holes or missing IMA calibration causes uneven cylinder contribution. Recode ECM and verify washer seating.
Fuel Rail / System Pressure Too High
Spill line backpressure or stuck metering valve prevents rail depressurization, creating overpressure risks under load.
Cross-Reference & Compatibility
Sister parts, same-platform variants, and known incompatibilities.
Technical Diagnostic & Service Protocols
Authoritative field procedures, diagnostic testing thresholds, and service SOPs for this assembly.