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. Bosch also makes a factory-remanufactured version of the same injector, Bosch 0986435597, which we list separately; 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 and we will confirm the exact match against your build before anything ships. That check is free and takes a few minutes.

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. We verify fitment against your engine serial, VIN or build date before anything ships, 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.