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MOTRS

240Z / 260Z / 280Z

1969-1978 / Coupe / Japan

All 240Z / 260Z / 280Z problems All workshop issues
Critical Engine

Head Gasket Failure

Symptoms

Coolant loss with no visible external leak. White smoke from the exhaust. Milky residue on the oil filler cap. Overheating. Coolant in the oil or oil in the coolant.

Cause

The L-series head gasket is a composite design that deteriorates with age, thermal cycling, and overheating events. The long inline-six cylinder head is prone to distortion if overheated.

Fix

Replace the head gasket.

The head must be removed and checked for flatness, have it machined if distorted (0.05 mm maximum distortion is the limit).

While the head is off, replace the valve stem seals and inspect the cam and followers.

Cost: $300-600 for parts (gasket set, head bolts, valve seals), plus machining ($150-300).

A competent home mechanic can do this job in a weekend.

Cost mentioned in fix
Cost: $300-600 for parts$150-300

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// More 240Z / 260Z / 280Z problems

Other known issues

Common Engine

SU Carburettor Wear and Tuning Issues (240Z, 260Z)

Poor idle, hesitation on acceleration, rich or lean running, black smoke, poor fuel economy, difficult starting. The engine may run well at some RPMs but poorly at others.
Common Engine

Fuel Injection Faults (280Z)

Hard starting (especially cold), rough idle, hesitation, rich or lean running, stalling. The engine management warning light may illuminate.
Critical Engine

Timing Chain Stretch

Rattling or slapping noise from the front of the engine, particularly on cold start. The noise may diminish as the engine warms but does not fully disappear.
Common Engine

Valve Stem Seal Deterioration

Blue-grey smoke on startup (after the car has been sitting). Blue smoke on deceleration (lifting off the throttle after sustained acceleration). Oil consumption increases, typically 1L per 2,000-3,000 km.
Minor Rust

Structural Rust, Floors, Sills, Strut Towers

Perforations in the floor pans, sill (rocker panel) box sections, and front strut tower mounting points. In advanced cases, the floorboard flexes underfoot, the sills crumble when prodded, and the strut towers crack under suspension load.
Common Rust

Battery Tray Corrosion

The battery tray (right-hand side of engine bay on RHD cars) corrodes and eventually perforates. Rust spreads into the inner guard and firewall.
View all 17 240Z / 260Z / 280Z problems