0445120305 Bosch Common Rail Injector 5268436 for Komatsu PC350 PC360 PC390 & Cummins QSL9

Genuine new Bosch 0445120305 common rail fuel injector (OE Cummins 5268436, Komatsu 6746113100) for Komatsu PC350, PC360 and PC390 hydraulic excavators, the Komatsu D65-17 bulldozer and Cummins QSL9 8.9 L engines. It is supplied new in the original sealed Bosch box, made in Brazil, and is covered by a 1-year manufacturer global warranty.

This is a solenoid-actuated CRIN3-18 injector for heavy-duty common rail systems. It meters and atomises the fuel delivered from the rail under full system pressure, so a correctly working unit restores the rated injection quantity, the intended spray pattern and the return-flow balance across all six cylinders.

Also known internationally as: Common Rail Injector (EN), Common-Rail-Injektor (DE), Injecteur Common Rail (FR), Iniettore Common Rail (IT), Inyector Common Rail (ES), Injector Common Rail (RO) - Bosch 0445120305 for Komatsu and Cummins.

Key features

Product details

OEM cross-reference numbers

Compare your original part number before ordering. Vehicle or machine model alone is not enough for compatibility confirmation.

Engine applications

Machine compatibility

Compatibility must always be verified by the original part number, OEM number or engine serial number. Machine model alone is not sufficient, because Komatsu and Cummins used different injector variants depending on build date, emissions stage and power rating.

Technical information

Related diesel fuel system components

Manufacturers fitted different variants of these components depending on engine build, power rating, emissions stage and production date, so another code may be the correct one for your machine. Identification is by the number on the fitted part, not by the machine model.

Shipping and warranty

Frequently asked questions

How do I know the Bosch 0445120305 fits my Komatsu excavator? Read the number stamped on the injector currently fitted, or the number in the machine's parts documentation. If it reads 0445120305, Komatsu 6746113100 (6746-11-3100) or Cummins 5268436, this is the correct injector. Komatsu built the PC350, PC360 and PC390 in several emissions stages and power ratings, so the machine model on its own does not confirm the fit.

What condition is this injector supplied in? It is a genuine new Bosch injector in the original sealed Bosch box, made in Brazil, and it carries a 1-year manufacturer global warranty. The photographs on this page show the actual packaging and the injector as it is delivered.

Is Komatsu 6746113100 the same part as this injector? Yes. Komatsu 6746113100, written 6746-11-3100 in Komatsu documentation, is the Komatsu part number for this Bosch injector. Cummins lists the same unit as 5268436, and Komatsu also references 5268436 because the engine is a Cummins-derived SAA6D114.

Does this injector need an IMA or IQA code written to the ECU? No. This CRIN3-18 injector is supplied without an individual injector accuracy code, so there is no calibration value to enter with a diagnostic tool after installation. Fitting is mechanical and electrical only.

Should I replace all six injectors at the same time? We recommend testing and replacing the complete set. The six injectors have run the same hours and are worn to a similar degree, so fitting one new injector next to five worn ones leaves the cylinders working unevenly. The new injector then runs under a different load than the rest and wears faster, which is why a partial replacement often ends in a second repair.

What is in the box? One injector, one injector body O-ring and one nozzle sealing washer, in the original Bosch packaging. Fitting the supplied new sealing washer is required, because the used washer is deformed by the clamping load and will not seal the combustion chamber again.

Do I also need a new connector tube? The injector connector tube F00RC00647 is the high-pressure link between the rail line and the injector, and its sealing cone is the part that suffers when an injector is removed after long service. Inspect it whenever the injector comes out; a scored or eroded cone is replaced, not lapped.

Will this injector work on a Cummins QSL9 engine outside a Komatsu machine? The injector is defined by the engine, not by the machine it sits in. Cummins QSL9 engines of 8.9 L built from 09/2010 in the 169-280 kW range use this unit, whether the engine is installed in an excavator, a generator set or a truck. Confirm with the Cummins engine serial number and the number on the fitted injector.

Do you ship worldwide? Yes, we ship worldwide.

Can I buy six pieces for a complete engine? Yes. Stock is held for this part number and six pieces can be ordered from this page; contact us before ordering if you need more than the quantity shown in stock.

Common symptoms of a failing common rail injector

On a Komatsu PC350, PC360 or PC390, a failing injector usually shows first as a rough, uneven idle with an audible knock from one cylinder, black or grey smoke under load, and a machine that no longer holds hydraulic performance when the engine is asked for full power. Excessive internal leakage raises the return flow, so the engine cranks longer before starting and may stall shortly afterwards, and the controller stores rail-pressure and cylinder-balance diagnostic trouble codes. A professional fuel-system test must be carried out before replacing any parts, to confirm the injector is the actual cause of the fault.

Installation and system check

Before any injector is fitted, the fuel system on the machine must be checked for contamination, whatever caused the original fault. On this engine the place to look is the fuel filter and its housing: debris, water and sticky varnish-like deposits collect there first and are the clearest evidence of the state of the rest of the circuit.

Components found to be contaminated are cleaned or replaced. The tank, the supply and return lines, the filter housing and filters, the rail and the high-pressure pump all fall inside the circuit that has to be dealt with. High-pressure lines and injector connector tubes are replaced, not cleaned, because their internal bore and sealing cone cannot be verified after cleaning. Flush the system, fit new filters and bleed the system according to the manufacturer's procedure.

The usual cause on machines working away from a workshop is poor or contaminated diesel: fuel stored badly on site, tanks that are not cleaned periodically, and contaminated containers or bowsers used for refuelling. Carry out all testing required to establish that the injectors are the actual cause of the fault before replacing any part.

When fitting, use the new sealing washer supplied with the injector, seat the injector squarely in the cylinder head bore and tighten the clamp and the high-pressure line to the torque figures in the Komatsu or Cummins service documentation. No calibration code has to be written to the ECU for this injector. An injector fitted into a system that has not been decontaminated fails again within a short service period, and that failure is not covered by the warranty.

Before the new injector is fitted, the fuel supply system must be checked for contamination. Rust, water, sludge or varnish-like deposits, metallic debris or any other contaminant left in the tank, supply and return lines, filter housing or rail will damage the new injector within a short service period, and that damage is not covered by the warranty. Inspect and decontaminate the system, renew the filters and confirm that the fuel is clean before installation.