This air compressor (also known as air pump) is a core component of the heavy truck engine air supply system for FAW J7. Driven by the engine, it compresses air to build air pressure for the vehicle’s pneumatic braking system, air suspension and other pneumatic auxiliary devices. This is a water-cooled dual-cylinder air compressor, developed for Xichai CA6DM series Euro VI engines. Adopting high-precision crankshaft and piston assembly, wear-resistant cylinder liner and advanced valve plate structure, it features stable air output, low vibration and low heat generation during long-haul operation. The cast aluminum housing has good heat dissipation performance. Every air compressor undergoes air output, pressure holding and leakage testing before delivery. It solves common faults such as insufficient air pressure, slow air build-up and air pump oil leakage, serving as a key replacement spare part for engine overhaul.