Terex PT60 Dies When Warm and Refuses to Restart

[MikePhua]

Terex PT60 Background and Design
The Terex PT60 compact track loader was engineered for versatility in landscaping, construction, and utility work. Introduced in the late 2000s, the PT60 featured a 60-horsepower Perkins 404D-22T turbocharged diesel engine, a suspended undercarriage system for improved traction, and joystick pilot controls. Terex, originally founded in 1933, expanded into compact equipment through acquisitions and innovation, with the PT series gaining popularity for its smooth ride and low ground pressure.
The PT60 was designed to operate in tight spaces and soft terrain, making it ideal for residential grading, snow removal, and light excavation. However, as these machines age, some owners report a recurring issue: the engine runs fine when cold but dies after warming up and refuses to restart until it cools down.
Symptoms of Heat-Related Shutdown

• Engine starts and runs normally when cold
  
• After 20–40 minutes of operation, engine stalls abruptly
  
• Attempts to restart immediately fail—no crank or weak crank
  
• After cooling for 30–60 minutes, engine restarts without issue
  
• No fault codes displayed on dash or diagnostic tool
  

This pattern suggests a thermal failure in electrical or fuel delivery components rather than a mechanical issue.
Terminology and Component Notes

• Perkins 404D-22T
  A four-cylinder turbocharged diesel engine known for fuel efficiency and compact design. Used in multiple compact machines.
  
• Fuel Solenoid
  An electrically actuated valve that controls fuel flow to the injectors. If it fails when hot, fuel delivery stops.
  
• Crankshaft Position Sensor
  Monitors engine rotation and signals the ECM to manage timing and injection. Heat can cause intermittent failure.
  
• ECM (Engine Control Module)
  The onboard computer that manages engine functions. Sensitive to voltage fluctuations and thermal stress.
  
• Starter Relay
  A switch that sends power to the starter motor. Heat can cause internal resistance or contact failure.
  

Common Causes of Heat-Induced Stalling

• Fuel Solenoid Overheating
  A failing solenoid may work when cold but lose magnetic strength when hot, cutting off fuel. Replacing with a high-temperature-rated unit often resolves the issue.
  
• Sensor Failure Under Heat Load
  Crankshaft or camshaft position sensors can degrade internally. When hot, they may send erratic signals or none at all, causing the ECM to shut down the engine.
  
• ECM Voltage Drop or Thermal Shutdown
  If the ECM is mounted near heat sources or lacks airflow, it may enter a protective shutdown mode. Relocating or shielding the ECM can help.
  
• Starter Relay or Solenoid Resistance
  Heat increases electrical resistance. A marginal relay may fail to engage the starter when hot. Replacing with a heavy-duty relay is recommended.
  
• Battery Cable Expansion and Ground Faults
  Heat causes cable expansion, which can loosen connections. Inspect and tighten all ground points and battery terminals.
  

Field Anecdotes and Practical Solutions
A contractor in Arizona reported that his PT60 would die after 30 minutes of mulching work. After replacing the fuel filters and checking the lift pump, the issue persisted. Eventually, he discovered the fuel solenoid was losing voltage when hot. Installing a new solenoid with a heat shield resolved the problem permanently.
In another case, a snow removal operator in Ontario experienced no-crank conditions after warm-up. The starter relay tested fine when cold but failed under heat. Replacing the relay and rerouting the wiring away from the exhaust manifold restored reliable starting.
Diagnostic Workflow for Heat-Related Shutdown

• Step 1: Monitor Fuel Solenoid Voltage When Hot
  Use a multimeter to check voltage at the solenoid immediately after shutdown. If voltage drops or disappears, trace wiring and test relay.
  
• Step 2: Scan for Sensor Faults
  Use diagnostic software to check crankshaft and camshaft sensor readings. Replace sensors if values are erratic or missing when hot.
  
• Step 3: Inspect ECM Location and Wiring
  Ensure ECM is not exposed to direct engine heat. Check for melted insulation or loose connectors.
  
• Step 4: Test Starter Relay Under Load
  Use a heat gun to simulate operating temperature and test relay response. Replace if resistance increases or contact fails.
  
• Step 5: Check Battery and Ground Integrity
  Measure voltage drop during cranking. Clean and tighten all terminals and ground straps.
  

Preventive Measures and Long-Term Solutions

• Install heat shields around solenoids and relays
  
• Use high-temperature-rated electrical components
  
• Relocate ECM away from engine block if possible
  
• Replace sensors every 2,000 hours or when symptoms appear
  
• Perform thermal imaging during service to identify hot spots
  
• Keep engine bay clean to improve airflow and cooling
  

Conclusion
Heat-induced shutdowns on the Terex PT60 are often caused by electrical components that degrade under thermal stress. By identifying weak links in the fuel and ignition systems, operators can restore reliability and avoid costly downtime. With proper diagnosis and preventive upgrades, the PT60 remains a capable and efficient machine for demanding job sites. In compact equipment, thermal resilience is just as important as horsepower.