Caterpillar original Common Rail Fuel Injector Replacement: 10R-7939, for heavy duty diesel engine application, 320-0680, 320-0677, 321-0990 original new injector

As a purpose-built heavy-duty fuel system component, the Caterpillar 10R-7939 original common rail injector is engineered to meet OEM specifications for CAT C6.4, C6.6 and Perkins 1106 series industrial diesel engines. It is a direct-fit replacement compatible with a range of Caterpillar equipment including D6N series dozers, 930H wheel loaders, 928HZ, 953D and IT28G machines, as well as industrial power units and generator sets. As a high-demand aftermarket part, it supports OEM replacement, engine remanufacturing, fleet maintenance and global spare part distribution use cases.

Constructed from hardened alloy steel with a precision multi-hole nozzle and micron-level machining tolerances, this injector operates at pressures up to 2000 bar in high-pressure common rail systems. The ECU-controlled solenoid precisely actuates the needle valve to deliver finely atomized fuel, optimizing combustion efficiency, reducing fuel consumption and exhaust emissions, while enhancing cold-start performance, engine responsiveness and long-term service life. Its corrosion-resistant surface treatment delivers reliable performance in harsh operating conditions.

Every 10R-7939 injector undergoes 100% factory testing covering injection quantity, return flow, leakage, response time, spray pattern and solenoid resistance to ensure consistent quality. Routine maintenance follows standard diesel injector guidelines, including use of high-quality fuel, regular filter changes and periodic balance testing. It serves construction, mining, power generation, agriculture, marine and industrial sectors, with no modification required for direct installation.