High-Temperature Issues in Construction Machinery Cooling Systems – Key Points

1. Cooling System Performance Deficiency (Most Common Cause)

• Fan speed and belt condition: Slipping or worn belts reduce fan RPM and cooling efficiency. Check fan speed with a tachometer; replace belts if the top surface is flush or recessed relative to the pulley. Use quality belts from reputable suppliers; worn pulleys also require replacement.

• Airflow obstruction: Radiator clogging, debris, blocked airflow paths, or reversed fans reduce cooling capacity. Use an anemometer to verify airflow at critical points.

• Water pump efficiency: Worn impellers or reduced flow can limit coolant circulation.

• Radiator condition: Internal clogging, scale, or debris can reduce heat dissipation; temperature differential across the radiator can help diagnose problems.

• Engine exterior cleanliness: Dirt or grease can impede heat transfer.

• Special cases: Engine layouts, series/parallel radiator configurations, or exhaust-jet cooling may affect system performance.

2. Excessive Heat Generation

• Overloading or underpowered engines

• Faulty thermostats

• Incorrect fuel timing or excessive injection causing incomplete combustion

• Intercooler failure, abnormal injection pressure

• Poor lubrication causing excessive friction in crankshaft/rods

• Severe hydraulic system wear (internal leakage) adding heat if oil cooler is in series with engine radiator

• Exhaust leaks or turbocharger duct leaks circulating hot gases into the engine compartment

3. Recommendations for Prevention and Diagnosis

• Always use qualified antifreeze, not ordinary water, to prevent scaling.

• Check fan speed, belts, pulleys, and airflow before considering major component failure.

• Verify water pump and radiator performance; replace if necessary.

• Use simple tools like tachometers and anemometers for accurate measurements rather than relying on visual inspection alone.

• Avoid unnecessary modifications unless operating in extreme or specialized environments.

Summary:
High-temperature issues are usually caused by minor, easily overlooked factors (belts, airflow, water pump) rather than fundamental design flaws. Methodical inspection, proper maintenance, and quality replacement parts are key to reliable cooling system performance.