| Parameter | Specification |
|---|---|
| COGENG Part Number | 371-3974 (3713974) |
| OEM Equivalent | Caterpillar 371-3974, 3713974 |
| Product Type | Common Rail Fuel Injector |
| Pack Quantity | 6 injectors (complete engine set) |
| Technology | Electronically controlled solenoid injector |
| Engine Compatibility | Caterpillar C7.1 |
| Equipment Compatibility | CAT 320, 320D, 320D2, 323D, 324D, 329D, 330D, 336D excavators |
| Brand | Part Number |
|---|---|
| COGENG | 371-3974, 3713974 |
| Caterpillar | 371-3974, 3713974 |
| Interchange | 374-9908, 374-9911, 374-9914, 390-8930, 390-8931, 390-8932, 453-3917, 453-3918, 453-3919, 10R-8622 |
Note: This injector has been updated to 371-3974 as a design improvement over earlier part numbers . Compatibility with serialized engine families may apply; check your engine serial number before ordering.TECHNICAL SPECIFICATIONS
| Parameter | Specification |
|---|---|
| Engine Compatibility | Caterpillar C7.1 (7.1L, 6-cylinder) |
| Cylinders | 6-cylinder engine |
| Injection System | High-pressure common rail |
| Control Type | Solenoid valve, electronically controlled by ECU |
| System Voltage | 24V DC (CAT standard) |
| Fuel Type | Diesel |
| Parameter | Specification |
|---|---|
| Injection Pressure | Up to 1,800 bar (26,100 psi) |
| Spray Pattern | OEM specification - precise atomization for complete combustion |
| Flow Rate | OEM specification (±3% tolerance across set) |
| Response Time | ≤ 0.5 ms |
| Parameter | Specification |
|---|---|
| Body Material | High-strength hardened alloy steel |
| Nozzle Material | High-speed tool steel, precision ground |
| Solenoid Coil | Class H high-temperature insulation (180°C) |
| Internal Filter | Stainless steel screen (20-30 micron) |
| Seals | Viton (FKM) high-temperature resistant |
| Weight (6-pack) | Approx. 4.5 - 6.0 kg (10 - 13 lbs) |
| Model | Series | Engine | Application |
|---|---|---|---|
| 320 | D2 / D2e / D3 | C7.1 | 6 injectors |
| 320D | D-Series | C7.1 | 6 injectors |
| 320D2 | D2-Series | C7.1 | 6 injectors |
| 320D2 GC | D2-Series | C7.1 | 6 injectors |
| 320D2 L | D2-Series | C7.1 | 6 injectors |
| 320D2e | D2-Series | C7.1 | 6 injectors |
| 320F | F-Series | C7.1 | 6 injectors |
| 323D | D-Series | C7.1 | 6 injectors |
| 323D2 | D2-Series | C7.1 | 6 injectors |
| 323D2 L | D2-Series | C7.1 | 6 injectors |
| 324D | D-Series | C7.1 | 6 injectors |
| 324D L | D-Series | C7.1 | 6 injectors |
| 329D | D-Series | C7.1 | 6 injectors |
| 329D L | D-Series | C7.1 | 6 injectors |
| 330D | D-Series | C7.1 | 6 injectors |
| 330D L | D-Series | C7.1 | 6 injectors |
| 330D2 | D2-Series | C7.1 | 6 injectors |
| 330D2 L | D2-Series | C7.1 | 6 injectors |
| 336D | D-Series | C7.1 | 6 injectors |
| 336D L | D-Series | C7.1 | 6 injectors |
| 336D2 | D2-Series | C7.1 | 6 injectors |
| 336D2 L | D2-Series | C7.1 | 6 injectors |
| 336D2 XE | D2-Series | C7.1 | 6 injectors |
| Engine Model | Displacement | Application |
|---|---|---|
| Caterpillar C7.1 | 7.1L (433 cu in) | Excavators, wheel loaders, industrial equipment |
| Caterpillar C7.1 ACERT | 7.1L | Tier 4 / Stage IV compliant models |
C7.1 Engine Specifications:
| Parameter | Specification |
|---|---|
| Displacement | 7.1L (433 cu in) |
| Cylinders | 6 in-line |
| Bore x Stroke | 105mm x 135mm |
| Fuel System | Common rail (high pressure) |
| Emission Standards | Tier 3 / Stage IIIA, Tier 4 / Stage IV |
Frequently Asked QuestionsNote: The C7.1 engine is a 6-cylinder, 7.1L displacement engine widely used in D, D2, and F series excavators. Verify compatibility with your equipment model, engine serial number, and ECU configuration before ordering. Contact COGENG with your machine details for exact application verification.
371-3974 Fuel Injector 6-Pack for Caterpillar C7.1 | Direct OEM Replacement for 320D Excavators
Q: What Caterpillar models and engines use the 371-3974 fuel injector?
A: The COGENG 371-3974 fuel injector 6-pack is a direct OEM replacement designed for Caterpillar C7.1 diesel engines where this injector part number is specified. The Cat C7.1 engine is commonly found in Cat 320D excavators and other Cat equipment including backhoe loaders, wheel loaders, and various industrial applications. This 6-pack provides a complete set of injectors for a full engine replacement. Always verify this part number against your engine's parts manual or the original injector's identification markings to confirm exact compatibility before ordering.
Q: What are the symptoms of failing fuel injectors on a Cat C7.1 engine in a 320D excavator?
A: Common symptoms include engine misfire on one or more cylinders, rough idling or uneven engine operation, loss of power under load, increased fuel consumption, black or white smoke from the exhaust, hard starting, fuel dilution in the engine oil, active diagnostic trouble codes related to injector circuits, or the engine entering a derate or limp mode. Faulty injectors can also cause internal engine damage due to incorrect fuel spray patterns or over-fueling if not addressed promptly.
Q: Why purchase the 6-pack instead of individual injectors?
A: The 6-pack provides a complete matched set of six injectors, which is recommended when multiple injectors show signs of wear or when performing a comprehensive engine fuel system overhaul. Replacing all injectors simultaneously ensures balanced fuel delivery across all cylinders, optimizes engine performance, and eliminates potential weak points that could cause future failures and costly repeat repairs.
Q: Is this injector set a direct plug-and-play replacement?
A: The COGENG 371-3974 fuel injectors are manufactured to exact OEM specifications for nozzle geometry, spray pattern, fuel delivery rate, electrical connector type, and mounting dimensions. They are direct replacements requiring no modifications when installed on compatible Cat C7.1 engines. However, injector trim codes must be programmed into the engine ECM using Caterpillar Electronic Technician (Cat ET) after installation to ensure optimal fuel delivery calibration for each cylinder.
Q: Does this injector require any programming after installation?
A: Yes, each new fuel injector has a unique injector trim code printed on the top of the injector body. These trim codes must be entered into the engine ECM using Cat ET or equivalent dealer-level diagnostic software to calibrate fuel delivery for each cylinder. Failure to program the trim codes will result in suboptimal engine performance, increased emissions, and potential engine damage. We strongly recommend installation and programming be performed by a certified Caterpillar service technician.
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