Datsun 240Z / 260Z Common Problems & Reliability
The Datsun 240Z and its successor, the 260Z, are iconic Japanese sports cars that challenged European supremacy in the 1970s by offering stunning E-Type-esque styling and reliable inline-six performance. In the UK, they are highly revered classic cars, prized for their beautiful proportions, mechanical simplicity, and tunability. Due to the UK’s damp climate, surviving original examples are exceedingly rare, with rust being the ultimate enemy of these cars. Reliability of the L-series engine is legendary, provided the twin SU-style carburetors are correctly tuned. It is a fantastic choice for classic car enthusiasts who want a stunning, reliable weekend cruiser or a base for a historic track car.
Select a Model Year Period
Detailed fault breakdown, symptoms, and estimated repair bills by production year.
Most Common Datsun 240Z / 260Z Faults & Repair Costs
Structural Corrosion (Rust)
The S30 chassis has many hidden box sections where moisture traps and eats the metal from the inside out. Frame rails, battery trays, and floor pans are the most common failure points.
Bubbling paint, Soft spots in floor/sills, Doors not aligning (suggesting chassis flex), MOT failure for structural rot
- Magnet test on sills and arches
- Hammer tap on frame rails
- Check under the battery tray for acid/water damage
Overheating & Head Gasket Failure
Older L24/L26 engines can suffer from silt buildup in the radiator or blocked coolant passages in the block, leading to localized overheating and warped heads.
Temp gauge climbing in traffic, White smoke from exhaust, Mayo-like sludge under oil cap
- Condition of coolant (should be clean)
- Ask when the water pump/radiator was last replaced
- Test for exhaust gases in coolant
Carburetor & Fuel System Issues
The Hitachi-SU carburettors require regular maintenance and adjustment. Worn needles, vacuum leaks and gummed-up passages cause flat spots, poor idle and hesitation. Parts are hard to source, with many owners converting to Webers.
Hesitation on acceleration, Stalling at idle, Rich or lean running, Strong fuel smell
- Check for smooth throttle response through the range.
- Look for fuel leaks around carburettors.
- Inspect fuel lines for perishing.
- Ask if Weber conversion has been done.
Wiring Loom Degradation
After 45+ years, the original wiring loom becomes brittle. Corroded fuse connections, cracked insulation and perished earth straps cause intermittent electrical faults throughout the car.
Intermittent lighting failures, Gauge erratic behaviour, Flickering dashboard lights, Blown fuses
- Inspect fuse box for corrosion.
- Check all earth points for clean metal contact.
- Test all electrical systems including lights and gauges.
- Consider a relay upgrade for headlights.
Buying a used Datsun 240Z / 260Z? Always check for hidden finance and write-off history.
Mechanical problems are only half the battle. Over 1 in 3 UK used cars checked have unpaid finance or accident write-off records that could cause you to lose the car or thousands in value.