Troubleshooting Sumitomo 120-3 Excavator Problems

[MikePhua]

The Sumitomo 120-3 is a popular model of excavators known for its durability and performance in a variety of tasks. However, like any machine, it can experience issues over time. This article discusses common problems faced by owners of the Sumitomo 120-3 and provides troubleshooting tips to help resolve them.
1. Common Issues with the Sumitomo 120-3
The following are some common problems that owners have reported with the Sumitomo 120-3:

• Engine Power Loss: One of the most frequent complaints is a loss of engine power, which can cause the excavator to operate inefficiently. This issue may be caused by several factors, including fuel system problems, clogged air filters, or issues with the turbocharger.
  
• Hydraulic Problems: Hydraulic issues are also commonly encountered, with symptoms such as slow movement of the boom or bucket, erratic hydraulic response, or total hydraulic failure. The most likely causes include low hydraulic fluid levels, leaks, or issues with the hydraulic pump or valves.
  
• Electrical Failures: Owners may encounter electrical issues such as malfunctioning dashboard indicators, failure to start, or issues with the control systems. These problems are often traced back to a malfunctioning alternator, faulty wiring, or a bad battery.
  
• Cooling System Failures: Overheating is another issue that can arise, typically caused by a malfunctioning radiator or cooling system components, or a clogged coolant line. If not addressed, this can lead to engine damage and a costly repair.
  

2. Troubleshooting Engine Power Loss
Engine power loss can severely impact the excavator’s performance, but it can be traced back to a few potential causes:

• Fuel System Issues: Check for clogged fuel filters or a blocked fuel line that could prevent the engine from receiving enough fuel. Also, inspect the fuel pump to ensure it is functioning properly.
  
• Air Filters: A clogged air filter can starve the engine of the air it needs to perform at peak efficiency. Check the air filter and replace it if necessary to restore engine power.
  
• Turbocharger Problems: A malfunctioning turbocharger can lead to a lack of power. Inspect the turbo for any signs of wear or damage, including oil leaks or low boost pressure.
  

3. Addressing Hydraulic Issues
Hydraulic problems are common in excavators and can be caused by several factors. Here’s how to troubleshoot them:

• Check Hydraulic Fluid Levels: Low fluid levels can lead to poor hydraulic performance. Ensure the hydraulic fluid is at the proper level and top it off if necessary.
  
• Inspect for Leaks: Hydraulic leaks can drain fluid and lead to performance issues. Look for leaks around the pump, hoses, and valves, and replace any damaged parts.
  
• Hydraulic Pump or Valve Malfunctions: If the pump or valves are malfunctioning, they may need to be repaired or replaced. A mechanic should inspect these components to determine if repairs are needed.
  

4. Resolving Electrical Problems
Electrical issues can range from minor inconveniences to major operational disruptions. Here’s what to check:

• Battery and Alternator: A dead battery or faulty alternator can cause starting problems and erratic electrical behavior. Test the battery voltage and inspect the alternator for proper operation.
  
• Wiring and Fuses: Inspect all wiring and fuses for signs of damage, corrosion, or loose connections. Replace any damaged components to restore proper electrical function.
  
• Control System Problems: If the control system isn’t responding correctly, it may be due to faulty sensors or a malfunctioning computer. Consult the machine’s diagnostic system to pinpoint the issue.
  

5. Overheating and Cooling System Failures
Overheating can be caused by issues in the cooling system. To troubleshoot:

• Radiator and Coolant Levels: Check the radiator for any blockages, damage, or leaks. Ensure that the coolant is at the proper level and in good condition.
  
• Cooling Fan: The cooling fan should be inspected to ensure it is operating properly. If the fan is not turning on or running inefficiently, it may need to be replaced.
  
• Clogged Coolant Lines: Over time, coolant lines can become clogged with debris or rust. Flush the system to remove any obstructions and ensure proper coolant flow.
  

6. Preventive Maintenance Tips
Regular maintenance can prevent many of the issues described above. Here are some tips:

• Regular Inspections: Schedule regular inspections to check for signs of wear or damage in the engine, hydraulics, electrical system, and cooling system. Catching problems early can prevent more expensive repairs.
  
• Clean Filters and Replace Fluids: Regularly clean or replace air filters, fuel filters, and hydraulic filters. Also, ensure that fluids are changed according to the manufacturer’s guidelines.
  
• Lubricate Moving Parts: Regularly lubricate moving parts, such as the boom, bucket, and arm, to prevent wear and ensure smooth operation.
  

7. Conclusion
The Sumitomo 120-3 is a reliable excavator, but like all machines, it can experience issues over time. Engine power loss, hydraulic failures, electrical issues, and overheating are some of the most common problems owners may face. By performing regular maintenance and troubleshooting specific issues as they arise, you can extend the lifespan of your equipment and keep it running efficiently.