• Carburetor mixture is too lean
  • Ignition timing is retarded or too advance
  • Radiator tubes blocked
  • Restricted air flow through radiator
  • Missing or damaged radiator shroud
  • Water jackets in engine block clogged with rust
  • Head gasket leaking exhaust into cooling system
  • Burnt valves
  • Valves need adjusting
  • Cracks in cylinder head
  • Radiator fins not attached to tube
  • Coolant leaks from hoses, gaskets or water pump
  • Incorrect radiator cap fitted
  • Defective radiator cap – will not hold pressure
  • Thermostat stuck
  • Water pump impeller slipping
  • Water pump impeller worn or broken
  • Excessive antifreeze in coolant mixture
  • Fan belt loose or slipping
  • Low coolant level
  • Incorrect thermostat fitted