Overheating
Symptoms
Temperature gauge climbs into the danger zone, particularly in traffic or on hot days. Coolant loss from the overflow.
Cause
Multiple factors compound on old Z-cars: a radiator that is partially blocked with scale, a thermostat that is stuck or partially open, a water pump with worn impeller, collapsed coolant hoses (the lower hose is most susceptible, it needs a spring insert to prevent collapse under suction), and a cooling fan that is not pulling sufficient air (the viscous clutch on the engine-driven fan wears out).
Fix
Address all components systematically.
A new aluminium radiator ($300-600) with more capacity than the original brass unit is a worthwhile upgrade.
Replace the thermostat ($20-30), water pump ($80-150), all coolant hoses ($100-200 for a complete set), and the fan clutch ($80-150).
A thermo-fan conversion (electric fan with a thermal switch) is popular and frees up engine power.
Cost: $200-400 for a quality setup.
Know something we don't?
Owned a Datsun 240Z / 260Z / 280Z? Share your experience with this issue. What worked, what didn't, costs, tips. Help the community.
Submit an update