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911 (Classic Air-Cooled)

1964-1989 / Coupe / Targa / Cabriolet / Germany

All 911 (Classic Air-Cooled) problems All workshop issues
Critical Electrical

CDI Ignition Module Failure (1969-1977)

Symptoms

Engine cuts out without warning, intermittent misfiring, no-start condition. The Capacitive Discharge Ignition module fails.

Cause

The CDI module is a sealed electronic unit that degrades with age and heat. Failure is typically intermittent before becoming permanent.

Fix

Replace the CDI module.

Aftermarket replacements are available and more reliable than the original Bosch units.

Cost: $300-$600.

Cost mentioned in fix
Cost: $300-$600

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Other known issues

Critical Electrical

Alternator and Charging Issues

Low charging voltage, flat battery, dim lights. The red generator/alternator light stays on or flickers.
Minor Engine

Cam Chain Tensioner Failure (3.2 Carrera)

The cam chain tensioner fails, allowing the duplex timing chain to go slack. The chain skips teeth on the sprockets, the camshaft timing shifts, and the valves collide with the pistons. The result is catastrophic, bent valves, damaged pistons, and potentially a cracked cylinder head.
Common Engine

Valve Guide Wear

Blue smoke from the exhaust on start-up (oil pooled on valve heads drains into the combustion chamber) and on the overrun (oil drawn past the guides by manifold vacuum). Increased oil consumption.
Critical Engine

Oil Leaks, The Usual Suspects

Oil residue on every surface of the engine. Active dripping in the garage.
Critical Engine

2.7-Litre CIS Engine, Nikasil Cylinder Scoring

Increased oil consumption, loss of compression, rough running, and blue exhaust smoke. The engine gradually loses power and efficiency.
Common Engine

Thermal Reactor Exhaust Damage (1975-1977)

Exhaust valve recession, burnt valves, cracked exhaust studs. The thermal reactor runs extremely hot to burn unburned hydrocarbons.
View all 13 911 (Classic Air-Cooled) problems