Choosing Between the CAT 345BL II and 345CL Excavators

[MikePhua]

The 345 Series and Its Evolution
Caterpillar’s 345 series excavators have long been a staple in heavy earthmoving, demolition, and infrastructure projects. The 345BL II, introduced in the early 2000s, was a refinement of the original B-series platform, offering robust mechanical systems and proven reliability. The 345CL, part of the C-series launched shortly after, marked a significant leap forward in electronic integration, hydraulic responsiveness, and operator comfort.
While both machines share a similar operating weight—around 50 metric tons—and bucket capacity in the 2.5 to 3.5 cubic meter range, their internal systems and field behavior differ substantially. Choosing between them depends on budget, application, and long-term maintenance strategy.
Terminology and Component Notes
- Load-Sensing Hydraulics: A system that adjusts pump output based on demand, improving fuel efficiency and control precision.
- ECM (Electronic Control Module): The onboard computer managing engine and hydraulic functions, diagnostics, and fault logging.
- Final Drives: Gear reduction units at each track, responsible for torque delivery and travel speed; wear here can be costly to repair.
- Undercarriage: The track system including rollers, idlers, sprockets, and chains; often the first major component to require overhaul.
- Swing Motor: A hydraulic motor that rotates the upper structure; performance here affects cycle times and operator control.
Performance and Operator Feedback
Operators who have run both machines consistently report that the 345CL is faster, smoother, and more fuel-efficient than the 345BL II. The C-series cab offers better visibility, reduced noise, and more intuitive controls. Hydraulic response is notably quicker, especially in multi-function operations like simultaneous boom and swing.
Mechanics also favor the 345CL for its improved diagnostics. The ECM provides clearer fault codes and system feedback, reducing guesswork during troubleshooting. While the B-series relied more on manual testing and mechanical inspection, the C-series allows plug-in diagnostics and real-time monitoring.
One technician described the C-series as the point where Caterpillar “finally caught up” with competitors like Komatsu in terms of electronics and operator interface.
Undercarriage and Component Wear at High Hours
A 345CL with 12,000 hours will likely require undercarriage work within the next year. This includes replacing track chains, rollers, and possibly sprockets. While this is expected at such hours, buyers should inspect for uneven wear, loose track tension, and oil leaks around the final drives.
Final drives themselves can last beyond 12,000 hours if properly maintained, but signs of trouble include:

• Excessive noise during travel
  
• Oil seepage at the hub seals
  
• Sluggish response or jerky movement
  
• Metal particles in drain oil samples
  

If purchasing a high-hour unit, request service records and consider oil sampling for final drives and swing motors. A well-maintained 345CL can still outperform a lower-hour 345BL II if the latter has been neglected.
Komatsu PC400 as an Alternative
Some buyers compare the CAT 345 series to the Komatsu PC400. While the PC400 is a capable machine with strong hydraulics and a durable frame, resale values tend to be lower. Komatsu machines often suffer from steep depreciation, especially at high hours. Once a major component fails, the cost of rebuilding can exceed the machine’s market value.
That said, a low-hour PC400 with documented service history can be a solid investment, particularly in markets where parts and support are readily available.
Caterpillar’s Excavator Legacy and Market Impact
Caterpillar began producing hydraulic excavators in the 1970s, with the 300 series becoming a global benchmark. The 345BL II was part of the second wave of large-frame machines, while the 345CL introduced the Next Generation platform with improved electronics and emissions compliance.
Sales of the 345CL were strong across North America, Europe, and Australia, especially in mining, quarrying, and infrastructure sectors. Its reputation for reliability and operator comfort helped solidify CAT’s dominance in the 45–55 ton class.
Conclusion
Between the CAT 345BL II and 345CL, the C-series offers clear advantages in speed, diagnostics, and fuel economy. While the B-series remains a workhorse with simpler systems, the CL is better suited for modern job sites and long-term ownership. For buyers evaluating high-hour machines, undercarriage condition and final drive integrity are critical. And when comparing to alternatives like the Komatsu PC400, consider not just performance—but the long-term cost of ownership and resale trajectory. In the end, the best machine is the one that fits your workflow, budget, and maintenance philosophy.