Komatsu PC200‑8 Engine Overheating – Causes, Error Codes, Fan Clutch Troubleshooting & Solutions

 

Komatsu PC200-8 Engine Overheating – Complete Troubleshooting Guide

The Komatsu PC200-8 is a Tier 3 electronic excavator powered by the SAA6D107E-1 engine. While it offers improved fuel efficiency and electronic control, it is also prone to engine overheating due to its complex cooling system and ECU logic. This guide provides a complete breakdown of symptoms, causes, error codes, troubleshooting steps, and solutions for PC200-8 overheating issues.

Symptoms of Engine Overheating in Komatsu PC200-8

• Temperature gauge rising above 100°C
• Engine derate mode activated
• Fan clutch running at full speed or not engaging
• Coolant boiling in reservoir
• White smoke from exhaust
• Warning light or buzzer on monitor
• Hydraulic functions slowing down

Common Causes of Overheating (General)

• Low coolant level
• Radiator and oil cooler blockage
• Thermostat stuck closed
• Water pump wear
• Airlock in cooling system
• Hydraulic overload

Komatsu PC200-8 Specific Causes of Overheating

• Electronic fan clutch failure – fan not engaging properly
• Coolant temperature sensor error – false readings trigger derate
• EGR cooler blockage – raises engine temp under load
• Fan solenoid valve failure – fan clutch not receiving signal
• Radiator fins clogged – especially in cotton or dusty areas
• ECU logic error – incorrect fan speed control

Komatsu PC200-8 Overheating Error Codes

• E03 – Coolant temperature high
• E411 – Water temperature sensor abnormal
• E451 – Fan clutch system abnormal
• E032 – Engine overload condition
• E372 – Hydraulic oil temperature high

Step-by-Step Troubleshooting for PC200-8 Overheating

1. Check Coolant Level and Quality

Ensure coolant is at proper level and free from contamination. Replace if rusty or oily.

2. Inspect Radiator and Oil Cooler

• Clean fins with compressed air
• Check for mud, cotton, or dust blockage

3. Test Fan Clutch Operation

• Check fan solenoid valve signal
• Verify fan clutch engages at high temp
• Replace clutch if slipping or noisy

4. Scan ECU for Error Codes

Use Komatsu diagnostic tool to check E03, E411, E451, and related codes.

5. Check Thermostat and Water Pump

• Replace thermostat if stuck
• Inspect water pump for leaks or bearing noise

6. Check EGR Cooler

Flush or replace if blocked. EGR heat can raise engine temperature under load.

7. Check Hydraulic Load

Overloaded hydraulic pump increases engine stress. Inspect relief valves and pump condition.

Solutions for Komatsu PC200-8 Overheating

• Clean radiator and oil cooler thoroughly
• Replace fan clutch or solenoid valve
• Replace thermostat and water pump if worn
• Flush coolant system and refill with Komatsu-approved coolant
• Fix wiring or sensor issues (E411, E451)
• Reduce hydraulic load during digging

Preventive Maintenance

• Clean radiator every 2–3 days in dusty areas
• Replace coolant every 1000 hours
• Check fan clutch operation monthly
• Inspect water pump and thermostat every 2000 hours
• Scan ECU monthly for early warnings

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