Kobelco SK024 Compact Excavator Fluid Specifications and Maintenance Insights

[MikePhua]

The SK024 and Kobelco’s Compact Excavator Lineage
The Kobelco SK024 was part of the company’s early compact excavator offerings, designed for tight urban spaces, utility trenching, and landscaping. Kobelco, founded in 1930 and headquartered in Japan, became a global leader in hydraulic excavator technology by the 1980s. The SK series helped establish Kobelco’s reputation for smooth hydraulic control, fuel efficiency, and mechanical reliability. Though the SK024 is no longer in production, many units remain in service across Europe and Asia, especially in small contracting fleets and rural municipalities.
Terminology Annotation

• Compact Excavator: A small hydraulic excavator typically under 6 metric tons, used for precision digging and confined-area work.
  
• Final Drive: The gear assembly that transmits torque from the hydraulic motor to the tracks.
  
• Hydraulic Reservoir: The tank that stores hydraulic fluid used to power cylinders and motors.
  

Engine Oil Grade and Capacity
The SK024 is powered by a small diesel engine, often a Mitsubishi or Yanmar variant depending on market. For optimal performance and longevity, the recommended engine oil is:

• Grade: SAE 15W-40 (API CF or higher)
  
• Capacity: Approximately 5.5 liters including filter
  

Operators in temperate climates should stick with 15W-40, while colder regions may benefit from SAE 10W-30 for better cold-start lubrication. Oil should be changed every 250 hours or annually, whichever comes first.
Hydraulic Oil Grade and Capacity
The hydraulic system is the heart of the SK024’s performance. It powers the boom, arm, bucket, and travel motors. Recommended specifications include:

• Grade: ISO VG 46 hydraulic oil (anti-wear type)
  
• Capacity: Approximately 45 liters including cylinders and lines
  

Hydraulic fluid should be checked weekly and changed every 1,000 hours. Filters must be replaced every 500 hours. Using high-quality anti-foaming oil reduces cavitation and improves control response.
Terminology Annotation

• ISO VG 46: A viscosity classification for hydraulic oil, indicating moderate thickness suitable for most climates.
  
• Cavitation: The formation of vapor bubbles in hydraulic fluid due to low pressure, which can damage pumps and valves.
  

Final Drive Oil Grade and Capacity
Each track motor contains a final drive assembly that requires gear oil for lubrication. Specifications include:

• Grade: SAE 90 gear oil (GL-5 rated)
  
• Capacity: Approximately 0.8 liters per side
  

Final drive oil should be changed every 1,000 hours or annually. Operators should inspect for leaks and check oil level monthly. A common failure point is the outer seal, which can allow water ingress and lead to gear pitting.
Preventive Maintenance Schedule
To keep the SK024 running reliably:

• Engine oil and filter: every 250 hours
  
• Hydraulic filter: every 500 hours
  
• Hydraulic fluid: every 1,000 hours
  
• Final drive oil: every 1,000 hours
  
• Fuel filter: every 250 hours
  
• Air filter: inspect monthly, replace as needed
  
• Track tension: inspect weekly
  

A contractor in Portugal reported improved fuel economy and smoother boom control after switching to synthetic hydraulic oil and replacing worn hoses. The machine, despite its age, continued to perform reliably on trenching jobs.
Terminology Annotation

• Track Tension: The tightness of the rubber or steel tracks, which affects traction and wear.
  
• Synthetic Hydraulic Oil: Engineered fluid with enhanced thermal stability and oxidation resistance.
  

Parts Availability and Restoration Advice
Though the SK024 is no longer in production, parts are still available through:

• Kobelco legacy dealers
  
• Aftermarket suppliers in Europe and Asia
  
• Salvage yards and online marketplaces
  
• Custom fabrication for bushings and seals
  

Operators restoring older units should:

• Document part numbers before disassembly
  
• Replace all seals and gaskets during hydraulic work
  
• Use torque specs from service manuals
  
• Flush systems thoroughly before refilling
  

In 2021, a restoration team in Spain rebuilt an SK024 for vineyard trenching. After replacing the hydraulic pump and resealing the final drives, the machine returned to full service and was used to install irrigation lines across 12 hectares.
Conclusion
The Kobelco SK024 remains a capable compact excavator when maintained with care and precision. Understanding fluid specifications and service intervals is key to preserving its performance. Whether digging footings or trenching for utilities, this machine continues to serve as a testament to Kobelco’s early engineering excellence. With proper fluids, preventive maintenance, and attention to wear points, the SK024 can remain a reliable partner in the field for years to come.