911 (Classic Air-Cooled)

1964-1989 / Coupe / Targa / Cabriolet / Germany

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

Critical Rust (Pre-1976 Cars)

Sill and Rocker Panel Corrosion

Symptoms

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

Cause

Road spray, blocked drain holes, and accumulated debris trap moisture inside the sill structure. Stone chips from the front wheels break the paint and expose bare steel.

Fix

Cut out corroded sections and weld in repair panels.

Full sill replacement is available from specialists.

Cost: $2,000-$5,000 per side.

Cost mentioned in fix

Cost: $2,000-$5,000 per side

Know something we don't?

Owned a Porsche 911 (Classic Air-Cooled)? Share your experience with this issue. What worked, what didn't, costs, tips. Help the community.

Submit an update

// More 911 (Classic Air-Cooled) problems

Other known issues

Minor Rust (Pre-1976 Cars)

Battery Box and Kidney Area Corrosion

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.

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