Locating the Temperature Sensor on the Kobelco SR135 Excavator

[MikePhua]

The Kobelco SR135 is a popular mid-sized crawler excavator known for its reliability, strong performance, and versatility in various applications such as construction, demolition, and digging. Like many heavy machinery engines, the SR135 is equipped with a range of sensors to monitor the temperature, oil pressure, and other crucial parameters to ensure the engine and hydraulic systems operate efficiently.
One of the key components that requires careful monitoring is the engine temperature. Overheating can lead to severe engine damage and costly repairs. Therefore, having access to the correct location of temperature sensors and understanding their functionality is vital for operators and maintenance professionals.
This article provides a comprehensive look at the temperature sensor located on the Kobelco SR135 excavator, how it works, and why it’s important for proper machine operation.
What is a Temperature Sensor?
A temperature sensor is a critical component in any heavy equipment engine system. It measures the temperature of various engine components, such as the coolant and oil, and sends this data to the vehicle’s control module. This information is then used to trigger cooling fans, shut down the engine in case of overheating, or activate warnings to alert the operator to a potential issue.
There are several types of temperature sensors in heavy equipment:

• Coolant Temperature Sensors (CTS): Measure the temperature of the coolant circulating through the engine.
  
• Oil Temperature Sensors: Monitor the temperature of the engine oil.
  
• Exhaust Gas Temperature Sensors (EGT): Measure the temperature of exhaust gases, providing vital data for the emission control system.
  

In the case of the Kobelco SR135, the coolant temperature sensor is the most crucial for monitoring the engine’s operational health and preventing overheating.
Why the Temperature Sensor is Important on the SR135
The temperature sensor on the SR135 ensures that the engine is operating within a safe temperature range. If the temperature exceeds the recommended limits, the sensor sends a signal to the control system to either activate cooling fans or display an alert to the operator.
Excessive heat can cause a range of issues in the engine, such as:

• Engine Seizing: When the engine overheats, it can seize due to the expansion of components.
  
• Oil Degradation: High temperatures can cause the oil to lose its lubricating properties, increasing friction and wear.
  
• Coolant Boiling: Overheating can cause coolant to boil, which may lead to a loss of coolant, further exacerbating the overheating issue.
  

Having an accurately located temperature sensor can be the difference between preventing an overheating issue early on and dealing with catastrophic engine failure.
Where is the Temperature Sensor Located on the Kobelco SR135?
For operators and maintenance professionals, it is essential to know where the temperature sensor is located to perform maintenance and troubleshooting tasks. On the Kobelco SR135, the coolant temperature sensor is typically located on the engine block, near the cylinder head, or close to the thermostat housing. The exact location may vary slightly depending on the specific model or year of manufacture, but the general placement is consistent across most Kobelco SR135 units.
Common Location for the Temperature Sensor:

• Engine Block: The temperature sensor is often mounted directly on the engine block, where it can measure the temperature of the engine coolant circulating through the block.
  
• Thermostat Housing: The sensor may also be placed near the thermostat housing, where the coolant is regulated before circulating through the engine.
  

If you are unable to find the sensor based on the above locations, referring to the service manual for the specific model of your SR135 is always a good idea. This document provides clear diagrams and part numbers to help you identify the sensor's exact position.
How to Troubleshoot the Temperature Sensor on the SR135
If the temperature gauge on your SR135 is giving inaccurate readings or the engine seems to overheat despite the gauge showing normal temperatures, the temperature sensor may be faulty. Here are some basic steps for troubleshooting the temperature sensor:
1. Check for Fault Codes:
Use a diagnostic tool to read fault codes from the SR135's onboard computer. If there’s an issue with the temperature sensor, the system may log a code, which can help pinpoint the problem.
2. Inspect the Wiring:
Inspect the wiring connected to the temperature sensor for signs of wear, corrosion, or loose connections. A broken or corroded wire can cause the sensor to provide false readings.
3. Test the Sensor:
If you're able to access the sensor, use a multimeter to test its resistance. A functioning temperature sensor will change its resistance based on the temperature. Compare the sensor’s reading with the specifications in the operator's manual to determine if it is working properly.
4. Flush the Coolant System:
Sometimes, debris or sludge in the coolant system can affect the temperature sensor’s readings. Flushing the coolant system and replacing the coolant may improve sensor performance and eliminate any interference.
5. Replace the Sensor:
If all else fails and the sensor is still malfunctioning, it may need to be replaced. Ensure that you use the correct part number and type of sensor as recommended by Kobelco for the SR135.
Maintaining the Temperature Sensor
Proper maintenance of the temperature sensor and surrounding components is critical for the long-term health of your Kobelco SR135. Here are a few maintenance tips to keep in mind:
1. Regular Fluid Checks:
Regularly check the engine coolant level and condition. Low coolant levels or dirty coolant can cause the engine to overheat, making it harder for the temperature sensor to give accurate readings.
2. Clean the Engine Area:
Dirt and debris can accumulate around the temperature sensor and affect its performance. Periodically cleaning the engine and sensor area will ensure the sensor remains effective.
3. Inspect Wiring and Connectors:
The wiring and connectors to the temperature sensor should be checked regularly for wear or corrosion. Any damage to the wiring can cause the sensor to malfunction and provide inaccurate data.
4. Prevent Overheating:
Be proactive in preventing overheating by maintaining the cooling system. Regularly check the radiator, cooling fans, and hoses for blockages or leaks, as any issues in the cooling system can directly affect the performance of the temperature sensor.
Real-World Case Study: Early Detection Prevents Engine Overhaul
In a real-world example, a Kobelco SR135 owner noticed that the engine’s temperature gauge was fluctuating erratically during operation. Suspecting an issue with the sensor, the operator inspected the sensor and wiring, finding a small crack in the wire near the sensor. This crack was causing intermittent disconnections, leading to false temperature readings.
By replacing the faulty wire and recalibrating the sensor, the issue was resolved. This small fix saved the operator from an expensive engine overhaul that would have been necessary had the overheating issue gone undetected for a longer period.
Conclusion
The temperature sensor on the Kobelco SR135 excavator plays an essential role in maintaining the engine's health by providing accurate readings of coolant temperatures. Understanding where the sensor is located, how to troubleshoot it, and how to maintain it can help prevent serious engine damage caused by overheating. Regular maintenance and attention to detail are key to keeping your machine running smoothly and ensuring its longevity.
By staying proactive with sensor checks, fluid maintenance, and overall system inspections, you can avoid costly repairs and maximize the performance of your Kobelco SR135 excavator.