Bosch 0445120231 is a new, genuine Bosch common-rail injector for Cummins QSB4.5, QSB5.9 and QSB6.7 industrial engines. It replaces Cummins 5263262 (earlier 4945969 and 3976372) and is also sold as Komatsu 6754-11-3011 and 6754-11-3102 for Komatsu equipment with these engines. Sold as one injector; the QSB4.5 uses four and the QSB5.9 and QSB6.7 use six.

This listing is the new injector. We also list a remanufactured version of the same injector, Bosch 0986435597 (Bosch Authorized Remanufactured, rebuilt by Valley Fuel Injection & Turbo); both fit the same engines. Replace when you see hard starting, rough running, smoke or low power traced to an injector, and clean the fuel system first, since dirt and water are what usually kill these injectors. Other QSB injectors look the same, for example Bosch 0445120251 (Cummins 5263314), so match the number.

Specifications

Fits / Applications

• Cummins QSB4.5 common-rail industrial engines
• Cummins QSB5.9 common-rail industrial engines
• Cummins QSB6.7 common-rail industrial engines
• Komatsu equipment with these Cummins-built engines that calls for Komatsu injector 6754-11-3011 or 6754-11-3102

Install with a new nozzle washer and O-ring and a clean, undamaged high-pressure connector (feed) tube. Replace the fuel filters and flush any contaminated fuel before start-up. Record the code printed on each injector; common-rail injectors on these engines may need that code entered with a service tool after install.

Part Numbers & Cross Reference

Cummins 5263262  ·  Cummins (suffix versions) 5263262NX, 5263262PX, 5263262RX  ·  Cummins (earlier) 4945969  ·  Cummins (earlier) 3976372  ·  Komatsu 6754-11-3011  ·  Komatsu 6754-11-3102  ·  Bosch (alternate) 0445120059  ·  Bosch reman 0986435597

Cross-reference numbers can change with engine serial, build year and emissions tier, so treat this list as a starting point. Send us your engine serial number before you order and we will help you confirm the exact match against your build. That check is free and takes a few minutes.

Frequently Asked Questions

Does Bosch 0445120231 replace Cummins 5263262 and Komatsu 6754-11-3011?

Yes. It replaces Cummins 5263262 (earlier 4945969 and 3976372) and is also sold as Komatsu 6754-11-3011 and 6754-11-3102 for Komatsu equipment with these engines.

How many 0445120231 injectors does a QSB4.5 or QSB6.7 take?

It is sold as one injector. The QSB4.5 uses four, and the QSB5.9 and QSB6.7 use six.

Is 0445120231 new or remanufactured, and is there a core?

This listing is the new, genuine Bosch injector in original packaging, sold outright with no core charge and nothing to send back. The remanufactured version, Bosch 0986435597, is listed separately. Both fit the same engines.

How do I tell 0445120231 from the other QSB injectors that look the same?

Match the number. Bosch 0445120251 (Cummins 5263314) and the Tier 4 Bosch 0445124019 (Cummins 5289266) look the same. Call 530-668-0818 with the number from your old injector, or the engine serial number (ESN) and CPL, and we confirm the match at no charge before anything ships.

Related Parts

• Cummins QSB 4.5L, 5.9L & 6.7L Fuel Injector | 0986435597 | Bosch Authorized Remanufactured by VFI
• Cummins ISB / QSB Injector Connector Tube | Genuine Bosch F00RJ01620
• Cummins QSB 4.5 & QSB 6.7 Tier 3 CP3 Injection Pump | Bosch 0986437310 Remanufactured
• Cummins QSB6.7 Tier 4 Common-Rail Fuel Injector | Bosch 0445124019 New (Cummins 5289266)

Why Buy From Valley Fuel Injection

We are a diesel fuel-injection and turbocharger shop in Woodland, CA, rebuilding pumps, injectors and turbos on our own benches since 1993, not a drop-ship storefront. When you call, you talk to the people who test these units. Send us your engine serial, VIN or build date before you order and we will help you confirm fitment, so the right part arrives the first time.

Not sure the injectors are the problem? We test and diagnose in-house before you buy. See our common rail injector testing and rebuild service.