Used Caterpillar 320C Excavator

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Here is a detailed introduction to the Caterpillar 320C hydraulic excavator in English.

Caterpillar 320C Hydraulic Excavator: A Detailed Overview

The Caterpillar 320C is a highly regarded and iconic hydraulic excavator that was manufactured by Caterpillar Inc. from the early 2000s, effectively succeeding the popular 320B series. It belongs to the "C-Series" generation of Caterpillar excavators and is renowned for its durability, reliability, and significant technological advancements that set new standards for performance, operator comfort, and serviceability. Even decades after its release, the 320C remains a common sight on job sites worldwide, a testament to its robust engineering.

1. Key Innovations and C-Series Upgrades

The transition from the B-Series to the C-Series was a major leap forward. The 320C wasn't just a facelift; it introduced several critical systems that define modern excavators:

HEUI™ Fuel System (Hydraulically actuated, Electronically controlled Unit Injector): This was the most significant change. Unlike traditional mechanical fuel injection, the HEUI system uses high-pressure hydraulic oil (from the implement pump) to pressurize fuel within the injectors, controlled by the engine's Electronic Control Module (ECM). This allows for infinite control over injection timing, pressure, and duration, independent of engine speed. The result is more complete fuel combustion, lower emissions, reduced noise, and notably better fuel economy.
Advanced Hydraulic System: The 320C featured a highly responsive hydraulic system designed for precise control. It moved away from the 320B's setup to offer improved flow distribution for multi-function operations.
Enhanced Operator Station: The cab was completely redesigned with a focus on ergonomics, visibility, and reduced operator fatigue, moving away from the more utilitarian cabs of previous generations.
Improved Electronics and Monitoring: A more sophisticated monitor panel provided the operator with detailed machine information, diagnostic capabilities, and customizable work tool settings.

2. Engine and Powertrain

The heart of the 320C is its robust and proven engine.

Engine Model: Caterpillar 3066T (Turbocharged)
Type: 6-cylinder, 4-stroke, direct-injection diesel engine.
Displacement: 6.4 liters
Power Output:
- Gross Power: 110 kW (148 HP) @ 1800 RPM
- Net Flywheel Power (ISO 9249): 103 kW (138 HP) @ 1800 RPM
Key Features:
- HEUI Fuel System: As described above, this is the defining feature, optimizing combustion across all load and speed conditions.
- Automatic Engine Speed Control (AESC): A fuel-saving feature that automatically reduces engine RPM to idle when the hydraulic controls are in neutral for a preset amount of time, significantly reducing fuel consumption and noise.
- Radiator and Cooling: A high-efficiency, side-by-side cooling system with a suction fan pulls air through the radiator, hydraulic oil cooler, and charge air cooler for effective heat rejection in high-ambient conditions. A viscous fan clutch further improves efficiency by modulating fan speed on demand.

3. Hydraulic System: The Power Behind the Work

The hydraulic system is engineered for power, speed, and fine control, enabling the 320C to handle everything from delicate grading to heavy mass excavation.

System Type: A load-sensing, closed-center system with variable-displacement piston pumps. This system produces flow and pressure only on demand, minimizing parasitic losses and saving fuel.
Main Implement Pumps: Two variable-displacement axial piston pumps providing high-output flow.
Maximum Total Implement Flow: Approximately 410 L/min (108 gal/min).
System Pressure:
- Implement Circuit: 34,300 kPa (4,975 psi)
- Swing Circuit: 27,500 kPa (3,990 psi)
Digging Forces (with standard 2.5 m / 8'2" stick):
- Bucket Digging Force: 152 kN (34,170 lbf) - This is a class-leading figure, providing exceptional breakout power.
- Stick Digging Force: 111 kN (24,950 lbf)
Work Modes: The operator can select different work modes to match the machine's performance to the application:
- Heavy Lift Mode: Boosts system pressure for superior lifting capacity.
- Breaker Mode: Configures hydraulic flow and pressure for one-way and two-way flow attachments.
- User-Defined Modes: Allows for custom flow and pressure settings for specialized tools like thumbs, shears, or tiltrotators.
Boom and Stick Regeneration Circuits: These circuits recycle hydraulic oil from the return side of the cylinder to the supply side during boom-down and stick-in operations. This speeds up cycle times and prevents cavitation, contributing to both faster performance and better fuel efficiency.

4. Structure and Undercarriage

Caterpillar built the 320C's structure to withstand the most demanding applications.

Main Frame: A robust, box-section construction using thick steel plates, designed to absorb high-impact loads and torsional stresses. It's built for a long service life, often through multiple engine and hydraulic rebuilds.
Undercarriage: Available in standard (LC, or Long Carriage) and Long (L) configurations. The Long undercarriage provides superior stability, especially for heavy lifting and working on uneven terrain.
Track Frame: A heavily reinforced, press-formed pentagonal track frame provides excellent strength and durability.
Track Options: Typically equipped with sealed and lubricated track chains to extend pin and bushing life. Options included triple grouser shoes for general applications and rubber pads for working on asphalt or concrete.
Grease-Tensioned Track Adjusters: A standard feature for easy and safe track tensioning.

5. Operator Environment (The Cab)

The 320C cab was a major step forward in operator comfort and safety.

Cab Structure: A reinforced, sound-suppressed cab with thick, tinted glass windows on all sides, providing excellent visibility to the trench, the boom/stick, and the rear. The cab meets ROPS (Roll-Over Protective Structure) and TOPS (Tip-Over Protective Structure) standards.
Suspension Seat: A multi-adjustable, high-back suspension seat with adjustable armrests, reducing whole-body vibration and fatigue.
Joystick Controls: Low-effort, pilot-operated joysticks with proportional thumb-slider switches for controlling auxiliary attachments. This allows for simultaneous, precise multi-function control.
Monitoring System: A centrally located LCD monitor displays critical information such as fuel level, engine coolant temperature, hydraulic oil temperature, system warnings, and work tool settings. It also provides access to service and diagnostic codes, simplifying troubleshooting.
Climate Control: A fully automatic climate control system with multiple adjustable vents ensures a comfortable working temperature year-round.

6. Serviceability and Maintenance

Easy and fast maintenance was a central design theme of the C-Series, maximizing machine uptime.

Wide-Swinging Access Doors: Large, gas-strut-assisted doors open wide at ground level for access to the engine, hydraulic pumps, filters, and cooling package.
Grouped Filter and Fluid Locations: All major fluid fill points (engine oil, hydraulic oil, fuel) and filters (engine oil, fuel, hydraulic pilot and return) are centralized and accessible from the ground.
S•O•S (Scheduled Oil Sampling) Ports: Quick-connect ports are strategically located for easy extraction of fluid samples, allowing for a proactive maintenance program to detect wear before a failure occurs.
Ecology Drains: Standard drains on the engine oil pan, hydraulic tank, and radiator help safely control fluid flow during changes, preventing spills.
Radial-Seal Air Filter: A high-capacity, double-element air filter with a visual service indicator simplifies filter changes.

7. Work Tools and Attachments

The versatility of the 320C is greatly expanded by its ability to run a wide array of attachments. The auxiliary hydraulic lines are pre-plumbed to the end of the stick, and the monitor allows for quick configuration.

Buckets: A massive range of Cat Work Tools, including General Duty, Heavy-Duty, and Severe-Duty buckets, in various widths and capacities to match soil conditions.
Hydraulic Hammers: For demolition and rock breaking, with the dedicated breaker work mode.
Thumbs: Hydraulic thumbs, both rigid and progressive-link designs, for material handling, brush clearing, and scrap work.
Compactors and Plate Compactors: For trench compaction.
Multi-Processors, Shears, and Pulverizers: For heavy demolition and scrap processing.

Standard Specifications (Typical 320C L)

Feature	Specification
Operating Weight (LC)	~ 19,980 - 21,500 kg (44,050 - 47,400 lbs)
Engine Model	Cat 3066T
Net Flywheel Power	103 kW (138 HP)
Max Digging Depth (Standard Stick)	6.65 m (21'10")
Max Reach at Ground Level	9.94 m (32'7")
Bucket Digging Force	152 kN (34,170 lbf)
Fuel Tank Capacity	400 Liters (105.7 gal)

Summary and Legacy

The Caterpillar 320C is much more than just an old machine; it is a milestone in excavator evolution. It successfully introduced sophisticated electronic engine and hydraulic controls (HEUI, AESC, work modes) in a package that was tougher and more reliable than its predecessors. The combination of its legendary Cat 3066T engine, powerful hydraulic breakout force, and vastly improved operator environment made it the benchmark for 20-ton class excavators for many years. Its durability ensures that many units are still productive in the field, and it remains a sought-after model on the used equipment market for contractors who value simple, robust, and easily maintainable machinery.

Non flooded

No accident

Original product

Used Caterpillar 320C Excavator

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