This is the genuine Bosch 0432191273, a new nozzle and holder assembly for Mack diesel engines. It is a mechanical injector: the nozzle, spring and holder in one body, fed by a separate pump, with no solenoid on the injector itself. It replaces Mack 736GB421M2.

A worn nozzle and holder shows up as a miss, a fuel knock, black or white smoke, hard starting or fuel wash on one cylinder. Mack used many nozzle holders that look alike across engine models and ratings, so go by the Bosch or Mack number on your old injector, not by how it looks. One per cylinder.

Specifications

Fits / Applications

• Mack diesel engines that use Mack injector 736GB421M2
• Engines whose old injector is stamped Bosch 0 432 191 273
• One per cylinder

Fit a new sealing washer under the nozzle, clean the injector bore and tighten the hold-down to the Mack figure for your engine. Change the fuel filters and bleed the lines before the first start.

Part Numbers & Cross Reference

Mack 736GB421M2

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.

Frequently Asked Questions

What Mack number does Bosch 0432191273 replace?

It replaces Mack 736GB421M2. Bosch prints the number with spaces, 0 432 191 273, on the injector body.

Is this a genuine Bosch injector?

Yes. It is a new, Bosch-made nozzle and holder assembly, not a rebuild, so there is no core to return.

Which Mack engines does it fit?

It fits Mack engines built with injector 736GB421M2. Mack used many lookalike holders, so call 530-668-0818 with your engine model and serial number and the number on your old injector.

Is this an electronic injector?

No. It is a mechanical nozzle and holder assembly. The fuel is timed and metered by the pump, not by the injector.

Related Parts

• Case / New Holland 445T/M3, F4GE & F4CE 4.5L Mechanical Fuel Injector | Bosch 0432133761 New
• Case IH & New Holland FPT Cursor 13 Unit Fuel Injector | Bosch 0414703008 New (504287070)
• Lombardini LDW 1204/T Diesel Unit Injector (Pump-Nozzle Unit) | Bosch 0414001003 New

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.