Used Doosan DX420-7 Excavator

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Doosan DX420-7 Crawler Excavator Detailed Introduction

The Doosan DX420-7 is a 42-ton class heavy-duty crawler excavator developed by Doosan Infracore (now part of HD Hyundai Infracore) for high-intensity working scenarios. As an upgraded iteration of Doosan’s classic DX-7 series, it balances strong power, high fuel efficiency, exceptional durability and operator comfort, and is widely recognized in global construction machinery markets for its reliable performance in harsh working conditions.

1. Core Specifications

Parameter	Details
Operating Weight	41,500 – 43,000 kg (varies by bucket, counterweight and track shoe configuration)
Standard Bucket Capacity	1.9 – 2.4 m³ (2.1 m³ rock bucket as standard, custom buckets available for specific scenarios)
Rated Power	271 kW / 1,800 rpm
Max Digging Depth (standard arm)	6,810 mm (extended arm option available up to 7,850 mm)
Max Digging Reach	10,680 mm
Max Digging Height	10,120 mm
Bucket Digging Force	278 kN
Arm Digging Force	213 kN
Travel Speed	3.0 – 5.2 km/h
Swing Speed	9.2 rpm
Gradeability	35° (70%)
Emission Standard	EU Stage III / US Tier 3 (Tier 4 Final version optional for regions with strict emission requirements)

2. Powertrain System

The DX420-7 is equipped with the self-developed Doosan DL08P 6-cylinder, 4-stroke, water-cooled electronic common-rail turbocharged diesel engine, which delivers a peak torque of 1,600 N·m at 1,400 rpm, providing sufficient power reserve for heavy-load operations such as rock excavation.

Doosan’s exclusive Smart Power Control (SPC) system optimizes engine output and hydraulic pump flow in real time according to working load, reducing unnecessary fuel consumption by 5-8% compared with the previous generation model, without compromising working efficiency.
It is fitted with a two-stage heavy-duty air filter and large-capacity independent cooling system, adapting to high-dust, high-temperature and high-altitude working environments up to 4,000 m above sea level.

3. Hydraulic System

It adopts Doosan’s upgraded e-EPOS (Electronic Power Optimizing System) hydraulic control system, which precisely matches the output of dual variable piston pumps and main control valves, ensuring fast, smooth and coordinated compound movements (e.g. simultaneous boom lifting and swinging, arm retraction and bucket closing).

The main hydraulic system pressure reaches 34.3 MPa, providing strong digging force to cope with hard rock and compacted soil conditions.
A load-sensing valve automatically adjusts flow distribution according to operation requirements, reducing pressure loss and improving operation precision.
Optional auxiliary hydraulic pipelines support a variety of attachments including hydraulic breakers, grapples, rippers and augers.

4. Structural Durability

All key structural components of the DX420-7 have passed 10,000 hours of extreme working condition tests, designed for long-term heavy-load use:

The boom, arm and upper main frame are welded with high-strength wear-resistant steel, with reinforced rib plates added at stress concentration parts to resist impact and deformation.
The X-shaped lower frame adopts integrated casting technology, with high torsional resistance, adapting to uneven mine roads.
Optional 450mm/600mm/800mm wide track shoes are available; the standard heavy-duty track chain and carrier rollers have an extended service life, reducing long-term maintenance costs.
The standard rock bucket is covered with wear-resistant plates at the bottom and edge, and equipped with replaceable bucket teeth, suitable for long-term quarry and mining operations.

5. Operator Comfort

The DX420-7 is fitted with a ROPS/FOPS certified safety cab, with excellent sealing performance that reduces internal operating noise to below 75 dB(A):

A fully adjustable air suspension seat with lumbar support effectively reduces fatigue during long-hour operations.
An 8-inch full-color intelligent display clearly shows real-time working status (fuel level, water temperature, hydraulic oil temperature, fault codes, etc.), and supports one-click switching of 4 working modes (Power, Standard, Economy, Lifting) for different operation needs.
The light-force joystick, high-efficiency air conditioning, USB charging port, radio and large storage space provide a user-friendly working environment.
Large-area windshields and skylights provide a 360° panoramic view, improving operation safety.

6. Maintenance & Management Convenience

All daily maintenance points are arranged on the ground-accessible side, no need to climb the upper frame for routine inspection. Engine oil filters, fuel filters, hydraulic oil return filters and air filters are centrally arranged for quick replacement.
The hydraulic oil replacement cycle reaches 5,000 hours, and the engine oil replacement cycle is 500 hours under normal working conditions, reducing downtime.
The built-in Doosan Connect remote management system supports real-time monitoring of equipment working status, fuel consumption, location and fault information, helping fleet managers arrange maintenance and scheduling reasonably, reducing operation and management costs.

7. Typical Application Scenarios

The DX420-7 is suitable for a wide range of heavy-duty operations:

Open-pit mining and quarrying: ore stripping, rock loading, hydraulic breaker operation
Large-scale earthmoving: highway/railway subgrade construction, reservoir excavation, land reclamation
Heavy construction: foundation excavation of super high-rise buildings, port and wharf construction
Special material handling: bulk cargo loading, scrap steel handling with grapple attachments

Overall, the Doosan DX420-7 is a cost-effective heavy-duty excavator with high reliability, low operating cost and strong environmental adaptability, which is an ideal choice for customers engaged in large-scale construction and mining operations.

Non flooded

No accident

Original product

Used Doosan DX420-7 Excavator

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