911 (Classic Air-Cooled)

1964-1989 / Coupe / Targa / Cabriolet / Germany

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

Minor Rust (Pre-1976 Cars)

Battery Box and Kidney Area Corrosion

Symptoms

The front luggage compartment, particularly the passenger side where the battery sits, develops severe corrosion. The "kidney" panel, a complex curved panel between the inner wing and the front bulkhead, rots from trapped moisture.

Cause

Battery acid vapour corrodes the battery box and surrounding panels. The kidney area is a double-skinned structure that traps moisture between layers. Water from blocked windscreen drains pools in this area.

Fix

Cut out corroded metal and weld in repair panels.

The kidney panel is complex to fabricate and requires an experienced 911 body specialist.

Cost: $3,000-$8,000 depending on severity.

Cost mentioned in fix

Cost: $3,000-$8,000

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Other known issues

Critical Rust (Pre-1976 Cars)

Sill and Rocker Panel Corrosion

The sills (rocker panels) that run along the bottom of each door develop rust, perforation, and structural weakness.

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