This is the Alliant Power AP55110, an electronic unit injector remanufactured by Alliant Power for the Detroit Diesel Series 60 14.0L. It replaces Detroit injector 5237821, sold by Detroit as the exchange number R5237821. Detroit’s own part name puts 5237821 on the 14L with DDEC IV, and injector catalogs group it with the DDEC III / IV style injectors, not the later N3. Other catalogs list the same injector as Delphi EX637821 and Bosch RB5237821 (F00E200262). It is sold each, and the engine takes six.

The 14.0L and 12.7L Series 60 injectors look alike but carry different numbers, and the 14.0L itself used more than one. Detroit 5237820 is one digit away and is a separate part number, and later 14.0L engines moved to the N3 injector. The number on your old injector and the engine serial number decide which one you need. A miss under load, a rough idle, white or black smoke, fuel in the oil or a cylinder cutout test that points at one hole are the usual reasons these get replaced. A refundable core applies.

Specifications

Fits / Applications

• Detroit Diesel Series 60 14.0L DDEC IV engines built with injector 5237821
• Not the N3 injector used on later DDEC V engines
• Match by the number on the old injector and the engine serial number
• Six injectors per engine, sold each

Part Numbers & Cross Reference

Alliant Power AP55110  ·  Detroit Diesel 5237821  ·  Detroit Diesel exchange R5237821  ·  Delphi remanufactured EX637821  ·  Bosch remanufactured RB5237821  ·  Bosch F00E200262

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

Which Detroit Series 60 does the AP55110 fit?

The Series 60 14.0L with DDEC IV, built with Detroit injector 5237821. Check the number on your old injector, or call 530-668-0818 with the engine serial number and we will match it.

What numbers does the AP55110 replace?

Detroit 5237821 and R5237821. The same injector is listed elsewhere as Delphi EX637821 and Bosch RB5237821 (F00E200262).

Can I use the AP55110 in a 12.7L Series 60, or in place of 5237820?

Order it only to replace 5237821. Catalogs list 5237821 for the 14.0L, the 12.7L engines take other numbers, and 5237820 is a separate part number. Match the number on your old injector.

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

It is remanufactured by Alliant Power. A refundable core applies, and the deposit comes back when we receive your old injector. It is sold each, so order six for a full set.

Related Parts

• Detroit Diesel Series 60 12.7L EUI Unit Injector (Detroit 5235915) | Alliant Power AP55106 Remanufactured
• Detroit Diesel Series 60 12.7L EUI Unit Injector (Detroit 5237650) | Alliant Power AP55105 Remanufactured
• Detroit Diesel Series 60 12.7L EUI Unit Injector (Detroit 5237045) | Alliant Power AP55104 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.