Cooling System Troubles on the Case 1840 Skid Steer

[MikePhua]

The Legacy of the Case 1840
Introduced in the early 1990s, the Case 1840 skid steer loader quickly became one of the most popular compact machines in North America. Manufactured by Case Corporation, which merged into CNH Industrial in 1999, the 1840 was known for its mechanical simplicity, robust hydraulic system, and reliable Cummins 4B engine. With over 60,000 units sold globally, the 1840 remains a staple on farms, construction sites, and rental fleets. Its cooling system, while generally dependable, can develop issues over time—especially involving the fan and radiator assembly.
Cooling System Design and Function
The Case 1840 uses a belt-driven axial fan mounted directly to the engine crankshaft pulley. This fan pulls air through the radiator and oil cooler, maintaining optimal operating temperatures for both the engine and hydraulic system. The radiator is mounted vertically behind the operator’s seat, protected by a steel shroud and mesh guard. Key components include:

• Radiator core with aluminum fins
  
• Engine-driven cooling fan
  
• Fan shroud and guard
  
• Thermostat and coolant hoses
  
• Hydraulic oil cooler mounted adjacent to the radiator
  

The system is designed to operate efficiently in dusty environments, but airflow can be compromised by debris buildup, bent fins, or fan misalignment.
Common Fan and Radiator Issues
Operators have reported several recurring problems with the 1840’s cooling system:

• Fan blades contacting the radiator core
  
• Excessive vibration or noise from the fan assembly
  
• Overheating during extended operation
  
• Coolant leaks from the radiator seam
  
• Reduced airflow due to clogged fins or damaged shroud
  

One frequent issue involves the fan blades striking the radiator, causing bent fins and coolant loss. This typically results from worn engine mounts or a misaligned fan pulley. If the engine shifts slightly under load, the fan can move out of its designed clearance zone.
Diagnosing Fan-to-Radiator Contact
To identify fan interference:

• Inspect radiator fins for fresh gouges or bent sections
  
• Check fan blade tips for wear or deformation
  
• Measure clearance between fan and radiator with the engine off
  
• Examine engine mounts for sagging or cracked rubber
  
• Verify pulley alignment and belt tension
  

In one case from Iowa, a contractor noticed a rhythmic clicking noise during operation. Upon inspection, he found that the fan had shaved a groove into the radiator core. The root cause was a collapsed front engine mount, which allowed the engine to tilt forward under torque. Replacing the mount and realigning the fan resolved the issue.
Solutions and Preventive Measures
To prevent fan-related damage:

• Replace worn engine mounts every 2,000 hours or as needed
  
• Install a reinforced fan shroud with tighter tolerances
  
• Use a shorter fan spacer to increase clearance
  
• Upgrade to a flex-blade fan that deforms under load
  
• Clean radiator fins weekly with compressed air or low-pressure water
  

Some operators retrofit their 1840s with electric fans mounted externally. While this reduces mechanical load on the engine, it requires careful wiring and relay installation to avoid electrical faults.
Radiator Repair and Replacement
If the radiator is damaged, options include:

• Brazing or epoxy patching for minor leaks
  
• Re-coring the radiator with new aluminum fins
  
• Full replacement with OEM or aftermarket units
  

Aftermarket radiators often use thicker cores and improved welds, offering better durability in harsh conditions. However, fitment must be verified, especially around the fan shroud and mounting brackets.
Field Anecdote and Practical Advice
In Saskatchewan, a farmer used his Case 1840 for manure handling and snow removal. One winter, the machine began overheating despite clean coolant and a new thermostat. After removing the radiator, he discovered that the fan had gradually bent several rows of fins, restricting airflow. He replaced the radiator and added rubber spacers to the engine mounts, preventing future contact. The machine ran cooler even under heavy load.
Additional Cooling Enhancements
For operators in hot climates or high-duty cycles:

• Install a high-flow water pump to improve coolant circulation
  
• Use extended-life coolant with anti-corrosion additives
  
• Add a temperature gauge with audible alarm
  
• Upgrade to a dual-pass radiator for better heat exchange
  

These modifications can reduce operating temperatures by 10–15°F, extending engine life and improving hydraulic efficiency.
Conclusion
The Case 1840 remains a workhorse in the compact loader category, but its cooling system demands attention—especially where fan-to-radiator clearance is concerned. By inspecting mounts, maintaining airflow, and upgrading components when needed, operators can avoid costly downtime and keep their machines running smoothly. Whether clearing snow or grading gravel, a properly functioning cooling system ensures the 1840 performs reliably in every season.