C4942479 (4942479) is a genuine Cummins Air Compressor Gear Cover / Access Cover Plate. It is a side-mounted sealing cover made of stamped steel / cast iron with a flat structure. It is primarily used to seal process holes, inspection ports, or unused mounting positions on the engine side (air compressor mounting or gear housing), preventing ingress of dust and contaminants, as well as leakage of oil and coolant. It is a basic protective component ensuring engine internal cleanliness and sealing integrity.
Technical Parameters
Part Number: C4942479 (shortened to 4942479)
Type: Engine Side Cover / Air Compressor Gear Cover / Blank-Off Plate
Material: Cold-rolled Steel (Stamped) / Cast Iron
Structure: Flat diamond/rectangular shape with 2 bolt holes
Dimensions: Approx. 146mm × 114mm × 14mm
Sealing Method: Requires gasket / sealant (sold separately)
Weight: Approx. 0.3-0.5kg
Cross Reference: 3930928, 4942478 (interchangeable)
Application
Applicable Engines: Cummins 4BT3.9, 6BT5.9, 6CT8.3, C8.3-C, ISLe, QSB series diesel engines.
Equipment:
- Commercial Vehicles: Dongfeng Tianlong, Tianjin, 153 series heavy-duty trucks
- Construction Machinery: Hyundai R210, Komatsu, Sany, XCMG excavators/loaders
- Industrial: Cummins generator sets, forklifts, air compressors
Mounting Location
- Engine Side (right side of cylinder block)
- Air Compressor Mounting Hole (blank-off when no compressor is fitted)
- Gear Housing Inspection / Process Hole
Common Faults & Troubleshooting
Fluid Leakage (Oil/Coolant)
- Causes: Gasket aging, cover deformation, uneven mounting surface, loose bolts
- Symptoms: Oil seepage around cover, dirt buildup, abnormal oil level drop
- Solution: Replace C4942479 cover and gasket; clean mating surface; torque bolts to 18-22N·m
Cover Rust / Damage
- Causes: Long-term oil corrosion, external impact, material aging
- Symptoms: Perforation, cracks, heavy rust, seal failure
- Solution: Replace with genuine C4942479 cover; inspect mounting surface for damage
Loose Installation / Noise
- Causes: Improper torque, vibration-induced loosening, worn locating holes
- Symptoms: Cover vibration, knocking noise during operation, air leakage
- Solution: Retorque bolts; replace damaged bolts; check for enlarged mounting holes