This is the Alliant Power AP55105, an electronic unit injector remanufactured by Alliant Power for the Detroit Diesel Series 60 12.7L, model years 1999 to 2002. It replaces Detroit Diesel 5237650, also sold as R5237650 and E5237650, and it crosses to Delphi EX637650 and Bosch RB5237650. The Series 60 is an inline six, so the engine takes six injectors. A refundable core applies.

The Series 60 used many unit injectors over its run, and they are split by model year, DDEC version and horsepower rating. They look alike and they are not interchangeable. Model year alone does not pick the injector, so match the number on your old one. The sister numbers are AP55104 (replaces 5237045) and AP55106 (replaces 5235915, earlier engines). A miss under load, white smoke at start-up, fuel in the oil or a cylinder cutout test that points at one hole are the usual reasons these get replaced.

Specifications

Fits / Applications

• Detroit Diesel Series 60 12.7L, 1999 to 2002
• Engines fitted with Detroit Diesel injector 5237650 (R5237650, E5237650)
• Six injectors per engine

On DDEC III and DDEC IV engines each unit injector carries a calibration code that is entered into the ECM with a scan tool when an injector is changed. Read the code off the injector before it goes in, set injector height and valve lash to the engine manual, and fit new O-rings.

Part Numbers & Cross Reference

Alliant Power AP55105  ·  Detroit Diesel 5237650  ·  Detroit Diesel reman R5237650  ·  Detroit Diesel E5237650  ·  Delphi EX637650  ·  Bosch reman RB5237650  ·  PAI Industries 609907X  ·  Interchange 5236952  ·  Interchange FS5237650  ·  Interchange 198560D  ·  Interchange 1480200020

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 Detroit Diesel number does the AP55105 replace?

It replaces Detroit Diesel 5237650, also listed as R5237650 and E5237650. It crosses to Delphi EX637650 and Bosch RB5237650.

Will the AP55105 fit any Series 60?

No. Series 60 injectors are split by year, DDEC version and rating, and this one replaces 5237650 only, an injector catalogs list for 1999 to 2002 12.7L engines. The sister numbers are AP55104 (replaces 5237045) and AP55106 (replaces 5235915). Call 530-668-0818 with the number on your old injector and your engine serial number and we will match it.

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

It is remanufactured by Alliant Power. A refundable core applies, and the core deposit is returned when we receive your old injector.

Does the injector need to be programmed after it is installed?

Yes. On DDEC III and DDEC IV engines the calibration code on each injector is entered into the ECM with a scan tool. Note the code on each injector and the cylinder it goes in before you fit it.

Related Parts

• Detroit Diesel Series 60 12.7L EUI Unit Injector (Detroit 5237045) | Alliant Power AP55104 Remanufactured
• Detroit Diesel Series 60 12.7L EUI Unit Injector (Detroit 5235915) | Alliant Power AP55106 Remanufactured
• Detroit Diesel DD13 12.8L GHG17 Common-Rail Fuel Injector | Bosch 0986435741 Remanufactured

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.