Caterpillar Fuel System Part Number Cross-Reference Guide: C6.4, C7, C7.1 & C9 (OEM vs Reman vs Engineering Numbers)

Introduction: Why Caterpillar Fuel System Part Numbers Are So Confusing

If you've ever tried to source a replacement fuel injection pump or fuel injector for a Caterpillar excavator, loader, or dozer, you've likely experienced the frustration of CAT part numbering. A single physical fuel pump on a CAT 320D excavator might be identified by four or five completely different numbers:

• New Production OEM Number: e.g., 320-2512 or 326-4635
• Superseded Service Number: e.g., 295-9126
• Caterpillar Reman Number: e.g., 10R-7675 or 20R-xxxx
• Tier-1 Supplier / Engineering Casting Number: e.g., Mitsubishi Heavy Industries 32F61-10302, Perkins 2641A405, or Delphi/Denso codes.

When heavy equipment is down on a job site, waiting days for a dealership to cross-reference numbers costs thousands of dollars. This engineering cross-reference guide breaks down the most commonly searched Caterpillar fuel injection pumps and injectors for C6.4, C7, C7.1, C9, and C4.4 engines, providing exact interchange tables so you can verify fitment immediately and order the right part.

Understanding Caterpillar Part Number Types

1. Caterpillar C6.4 Fuel System Interchange (CAT 320D Series)

The CAT C6.4 engine (a joint platform with Mitsubishi Heavy Industries) is the power unit in the world's most ubiquitous mid-size hydraulic excavator: the CAT 320D, 320D L, 321D, and 323D. Below is the master cross-reference table for C6.4 fuel pumps and common rail injectors:

C6.4 High-Pressure Fuel Injection Pump

C6.4 Common Rail Fuel Injector

2. Caterpillar C7 & C7.1 Fuel System Interchange

The 7.2L C7 engine underwent a major fuel system evolution throughout its production run, making accurate cross-referencing critical:

• HEUI Systems (Hydraulic Electronic Unit Injection): Used in earlier C7 ACERT engines (324D, 329D, 950H). These utilize a high-pressure oil actuation pump and mechanical fuel transfer pump.
• Common Rail Systems (HPCR): Used in later Tier 3/Tier 4 Interim C7 engines and all modern C7.1 engines (324E, 329E, 335F, 950K/M).

C7 & C7.1 Fuel Injection & Transfer Pumps

3. Caterpillar C4.4 / 3054C Fuel System Interchange

For compact excavators, backhoe loaders (such as the CAT 416E, 420E), and telehandlers powered by CAT C4.4 or 3054C engines (Perkins 1104 series collaboration):

4. Heavy-Duty C11, C13, C15 & C18 Transfer Pumps

For large earthmoving equipment, off-highway trucks (773G, 775G), and large excavators (CAT 345D, 349E, 374D):

How to Accurately Verify Fitment Before Ordering

To avoid receiving the wrong part, always follow this 3-step verification checklist:

1. Locate the Engine Serial Number (ESN) & Arrangement Number: Found on the metal data plate stamped onto the engine valve cover or block (e.g., ESN prefix like WDE, KHX, or KAL). Caterpillar parts catalogs are indexed primarily by engine prefix and arrangement number, not just machine model.
2. Inspect the Stamped Tag on Your Old Pump: Clean the identification plaque riveted to the pump housing. You will often see both a Cat number (e.g., 320-2512) and a manufacturer code (e.g., 32F61-10302). Either number can be cross-referenced using our tables above.
3. Check for System Generation (HEUI vs. HPCR): If your C7 engine has high-pressure steel fuel lines running from a central tube (rail) directly to the injectors, it is a Common Rail system (requiring pumps like 476-8766). If it has wiring harnesses going through the valve cover with high-pressure oil lines, it is a HEUI system (requiring pumps like 319-0677).

Still Not Sure? We Can Cross-Reference It For You

If your part number is worn off or you have an unusual arrangement number, don't guess. Send a photo of your engine dataplate or old pump to our engineering support team, and we'll identify the exact OEM-spec replacement within minutes.