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“Our mini excavator overheated and stopped working. We need someone to come for an on-site repair immediately”—we received this emergency consultation from a customer in Tokyo.
The target model was a KOBELCO SK30SR-6 mini backhoe. On-site, the machine also exhibited a lack of power and delayed operation, and the customer was understandably frustrated, stating, “I can’t get any work done like this.”

When we asked for details, we were surprised to learn that for five years since purchase, no scheduled maintenance had been performed even once, such as engine oil changes or fan belt inspections.
Upon arriving on site, the moment we opened the engine hood, the condition was obvious at a glance. We found that the fan belt had completely deteriorated and was falling apart, and overheating had occurred due to alternator charging failure and the cooling fan not operating.

With these issues occurring together, the machine’s operation appears to have become extremely sluggish.

[Key Repair Points]

• Replaced the deteriorated fan belt with a new one and optimized belt tension
  　⇒ To address fan belt wear and damage, which was the direct cause of the overheating, we carried out a fan belt replacement using genuine parts. We also adjusted the belt tension properly, restoring normal operation of the cooling fan and alternator.
• Inspected and adjusted the electrical system for alternator charging failure
  ⇒ Since insufficient voltage from the alternator had been confirmed, we performed a voltage test to check for charging issues. In addition to replacing the fan belt, we inspected for poor terminal contact and harness degradation, and implemented measures to prevent recurrence.
• Replaced consumables such as engine oil and coolant in one go and performed scheduled maintenance
  　⇒ As the machine had reportedly gone five years without maintenance, we thoroughly checked the basic scheduled maintenance items, including an engine oil change, coolant (LLC) top-up, and air filter cleaning. We carried this out as an opportunity to ensure you can continue using the machine with confidence.

[For Those with Similar Concerns]

Problems with heavy equipment can occur suddenly. As in this case, it is not uncommon for overheating and operational issues to be caused by fan belt deterioration, alternator charging failure, or cooling system trouble.

In particular, neglecting scheduled maintenance—such as “I have never changed the oil” or “I have never even opened the engine hood”—can sometimes lead to costly repairs.

Regardless of the model, our company has extensive experience handling cooling issues, electrical problems, and oil leak repairs for mini excavators, shovels, and wheel loaders from brands such as Kobelco, Yanmar, Kubota, and CAT (Caterpillar), allowing us to provide the fastest possible response.

If you notice even slight changes, such as “it seems sluggish lately” or “the sound or smell is different than usual,” please exercise caution. Because heavy machinery is expensive equipment, early inspections and preventive maintenance lead to significant cost reductions.

We also accept requests for periodic inspections and maintenance, so please feel free to contact us.

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