4N-3281 4N-3282 4N-3283 4N-3284 Fuel Injection Line Set for Caterpillar 3304 Engine

4N-3281 to 4N-3284 High-Pressure Fuel Injection Line Set for Caterpillar 3304

This 4-cylinder fuel injection line set—comprising OEM part numbers 4N-3281, 4N-3282, 4N-3283, and 4N-3284 (commonly written as 4N3281, 4N3282, 4N3283, and 4N3284)—is a replacement high-pressure nozzle piping assembly for Caterpillar 3304 and D330C diesel engines. Routed between the fuel injection pump housing and the cylinder head fuel injection nozzles, these seamless steel tubes deliver high-pressure diesel fuel to Cylinders 1 through 4.

Each fuel injection line is CNC-bent from thick-walled cold-drawn seamless steel tubing to match original factory geometry and comes pre-fitted with threaded union nuts to ensure leak-free sealing under continuous diesel injection pressure and engine vibration.

Cylinder Position & Part Number Breakdown

• Cylinder No. 1 Fuel Injection Line: 4N-3281 / 4N3281 / CA4N3281

• Cylinder No. 2 Fuel Injection Line: 4N-3282 / 4N3282 / CA4N3282

• Cylinder No. 3 Fuel Injection Line: 4N-3283 / 4N3283 / CA4N3283

• Cylinder No. 4 Fuel Injection Line: 4N-3284 / 4N3284 / CA4N3284

Compatible Excavators & Construction Machinery

Caterpillar 215 | Caterpillar 225 | Caterpillar 235 | Caterpillar D4D / D5B / D6C / D6D | Caterpillar 920 / 930 / 950 / 966C

Designed primarily for Caterpillar hydraulic excavators running 3304 and compatible 3300-series engines, with selected applications across dozers, wheel loaders, and motor graders:

• Caterpillar Excavators: 215, 225, 235

• Caterpillar Track-Type Tractors (Bulldozers): D4D, D4E, D5, D5B, D6C, D6D, D7F, D7G

• Caterpillar Wheel & Track Loaders: 920, 930, 950, 966C, 980B, 941, 941B, 951B, 951C, 955K, 955L, 977K

• Motor Graders & Other Equipment: 120, 120B, 120G, 12F, 12G, 130G, 140, 140G, 14E, 14G; Skidders 518, 528

Fitment Verification & Ordering

Please note that on 4-cylinder Caterpillar 3304 and D330C engines, part numbers 4N-3281 through 4N-3284 form the complete 4-line injector pipe set. On certain 6-cylinder 3306 / D333C configurations, these four lines serve Cylinders 1–4 alongside Cylinder 5 and 6 lines (6N-1965 and 6N-1966). Always verify your engine arrangement number and existing fuel line part numbers before ordering.