Cooling System Troubleshooting in Harsh Summer Conditions

[MikePhua]

Heat Stress and Engine Cooling Challenges
In regions like central Texas, summer temperatures routinely exceed 100°F, placing extreme demands on heavy equipment cooling systems. Machines operating under load for extended hours often face overheating risks, especially if their radiators are partially blocked or internally corroded. One operator reported that his dozer would begin to overheat after just a couple of hours of work, requiring manual cooling interventions such as pouring water over the radiator grille to reduce surface temperature.
This kind of workaround, while temporarily effective, points to deeper issues in the cooling system—either airflow restriction, internal coolant flow blockage, or degraded heat exchange efficiency. Understanding the root cause is essential to prevent long-term engine damage.
Terminology Notes

• Radiator Core: The central section of the radiator where coolant circulates through tubes and fins for heat dissipation
  
• Coolant Flow Path: The route coolant takes from the engine block through the radiator and back
  
• Fin Comb: A tool used to straighten bent radiator fins and restore airflow
  
• Non-Contact Thermometer: An infrared device used to measure surface temperatures without physical contact
  
• Degreaser: A chemical cleaner used to remove oil and grime from metal surfaces
  

Initial Diagnostics and Temperature Mapping
Before assuming the radiator is faulty, a temperature-based diagnostic approach can reveal whether the issue lies in the air or water side of the system. Using a non-contact thermometer, measure:

• Temperature of the upper radiator hose (hot coolant entering)
  
• Temperature of the lower radiator hose (cooled coolant returning)
  
• Air temperature entering the radiator
  
• Air temperature exiting the radiator
  

If the air exiting the radiator is nearly as hot as the air entering, airflow is likely restricted. If the coolant entering and exiting the radiator shows minimal temperature drop, internal blockage or poor heat transfer is the culprit.
A technician in Arizona once used this method to discover that his radiator fins were packed with fine dust and oil residue from months of desert grading. After a thorough cleaning, his machine ran 20°F cooler under identical load.
Cleaning Procedures and External Blockage Removal
To clean the radiator thoroughly without removing it:

• Access both sides of the radiator by removing shrouds or panels
  
• Use a garden hose with moderate pressure to flush debris from the fins
  
• Apply degreaser to oily areas and let it soak for 10–15 minutes
  
• Use o-ring picks or fin combs to straighten bent fins and improve airflow
  
• Finish with compressed air to dry and dislodge remaining particles
  

Avoid using high-pressure washers directly on the fins, as they can bend or puncture the core. For machines operating near vegetation or in dusty environments, this cleaning should be done monthly.
Internal Blockage and Coolant System Flushing
If external cleaning does not resolve the issue, internal flushing may be necessary. Signs of internal blockage include:

• Discolored coolant with rust or sediment
  
• Reduced flow from the water pump
  
• Coolant overflow or pressure buildup
  

To flush the system:

• Drain all coolant and remove the thermostat
  
• Fill the system with a radiator flush solution and distilled water
  
• Run the engine at idle for 30–45 minutes
  
• Drain and repeat until water runs clear
  
• Reinstall thermostat and refill with fresh coolant
  

If pond water or untreated well water was previously used, mineral deposits may have formed inside the radiator tubes. In such cases, chemical descaling or professional cleaning may be required.
Replacement Considerations and Cost-Benefit Analysis
If the radiator is severely corroded or leaking, replacement may be the most practical solution. Factors to consider:

• Cost of a new radiator versus professional cleaning
  
• Availability of aftermarket or OEM units
  
• Downtime required for removal and installation
  
• Compatibility with existing mounts and shrouds
  

A contractor in Louisiana replaced his radiator with a high-efficiency aluminum unit and reported a 25% reduction in operating temperature, along with improved fuel economy due to reduced fan load.
Preventive Maintenance Recommendations
To avoid future overheating:

• Use a 50/50 mix of ethylene glycol and distilled water
  
• Replace coolant every 500 hours or annually
  
• Inspect hoses and clamps monthly
  
• Clean radiator fins after every dusty job
  
• Install a temperature gauge with audible alarm for early warning
  

For machines working in extreme heat, consider adding a secondary fan or upgrading to a multi-row core radiator for increased cooling capacity.
Conclusion
Overheating in heavy equipment is often a symptom of neglected cooling systems rather than a single point failure. By combining temperature diagnostics, thorough cleaning, and smart maintenance practices, operators can restore cooling performance and extend engine life. Whether flushing the radiator or replacing it entirely, the goal is to ensure consistent heat dissipation under the harshest conditions.