911 (Classic Air-Cooled)

1964-1989 / Coupe / Targa / Cabriolet / Germany

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

Minor Engine

Cam Chain Tensioner Failure (3.2 Carrera)

Symptoms

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.

Cause

The original cam chain tensioner on the 3.2 Carrera uses a ratcheting mechanism that can stick or fail mechanically. Once the tensioner loses its preload, the chain has no take-up device and immediately goes slack. The failure often occurs during cold start when oil pressure is lowest.

Fix

Install the updated cam chain tensioner (the "update" or "improved" tensioner).

This is a proactive replacement, do not wait for symptoms.

A cold-start chain rattle is a warning that the tensioner is failing.

Replacement cost: $500-$1,000 including parts and labour.

The cost of ignoring it: $15,000-$25,000 for an engine rebuild.

Cost mentioned in fix

cost: $500-$1,000 including parts and labour$15,000-$25,000 for an

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Other known issues

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.

Common Transmission

915 Gearbox, Second Gear Synchro Wear

Second gear crunches or grinds on downshifts, especially when cold. The synchro cannot match shaft speeds before gear engagement. Over time, it worsens and eventually grinds on upshifts as well.

Common Transmission

915 Gearbox, Shift Linkage Slop

Vague, imprecise shifting. Difficulty finding gears, especially third and fourth.

View all 13 911 (Classic Air-Cooled) problems