138-8754 Diesel Fuel Injector for Caterpillar 3412E/3408E

138-8754 Caterpillar diesel fuel injector for 3412E/3408E

The 138-8754 Caterpillar diesel fuel injector is a one-piece Rayfuel aftermarket replacement for selected 3412E/3408E. This listing is intended for diesel repair shops, equipment owners, fleet maintenance teams and parts buyers who have already identified the injector by its complete marking. Browse related heavy-equipment parts in our Caterpillar diesel parts category.

This product is not presented as a genuine, original or OEM-boxed Caterpillar component. Caterpillar names, machine models, engine references and part numbers are used only for identification and fitment comparison. The required injector can change with engine serial number, machine serial number, arrangement number, production date, rated output and emissions specification.

Product identification

• MPN: 138-8754
• OE and cross-reference numbers: 138-8754, 0R-8624
• Application: Selected 3412E/3408E
• Product type: Diesel fuel injector assembly
• Quantity: 1 injector
• Brand: Rayfuel

Numbers written with or without hyphens may be alternate formats of the same reference, but similar-looking injectors are not automatically interchangeable. Internal calibration, nozzle specification, connector design, body configuration and engine control requirements can differ even when the exterior shape appears similar.

Caterpillar engine and machine fitment

This injector is listed for selected 3412E/3408E. Before ordering, compare every number on the removed injector and check the applicable engine or machine parts catalog. Where available, use the full engine serial number, machine serial number and arrangement information. A model name alone is not sufficient to confirm fitment.

The four-image gallery is provided for visual comparison. Check the electrical connector, fuel inlet, return connection, hold-down or mounting features, overall body profile and nozzle end. Visual similarity supports identification, but the complete part-number match remains the primary selection method.

Injector function and possible symptoms

A diesel fuel injector meters fuel and delivers a controlled spray into the combustion chamber. Correct injector operation supports reliable starting, stable idle, balanced cylinder contribution, consistent combustion and normal response under load. Its performance also depends on clean fuel, adequate supply pressure, correct high-pressure system operation, sound wiring and suitable engine mechanical condition.

Possible signs that an injector requires diagnosis include hard starting, extended cranking, rough idle, reduced power, abnormal combustion noise, excessive smoke, cylinder-balance irregularities, unusual return flow or injector-related fault codes. These symptoms do not prove injector failure. Filters, fuel contamination, air in the supply circuit, pressure-control problems, harness faults, compression loss and other engine issues can produce similar symptoms.

Testing and installation guidance

Professional diagnosis is recommended before replacement. Use the appropriate workshop procedure and calibrated test equipment for the relevant Caterpillar application. Keep all fuel-system connections clean and capped during service. Inspect related pipes, seals, fittings and mounting hardware, and replace required single-use items according to the service information for the engine.

Installation should be completed by a qualified diesel technician. Follow the specified tightening sequence and torque values. If the application uses injector trim, calibration or compensation data, confirm whether the code must be entered into the engine control module after installation. Do not reuse contaminated high-pressure components.

Before ordering the 138-8754 Caterpillar diesel fuel injector

Please confirm the complete part number, engine or machine model, serial information and old-part photos before ordering. The reference set for this listing is 138-8754, 0R-8624. Caterpillar publishes general information about replacement parts on its official parts website; exact selection should follow the correct serial-number-based catalog.

If any identification detail is uncertain, send clear photos of the complete injector marking and connector together with the engine or machine information through the Rayfuel OE-number inquiry page. Rayfuel can assist with number comparison, mixed-parts inquiries, wholesale quantities and export packaging.

Rayfuel aftermarket supply

Rayfuel supplies diesel injection parts for repair shops, distributors, equipment owners and international buyers. The 138-8754 Caterpillar diesel fuel injector on this page is supplied as one injector only. It does not include a multi-piece set, installation kit or additional injectors unless those items are explicitly listed separately.