XJ-S

1975-1996 / Coupe / Convertible / United Kingdom

All XJ-S problems All workshop issues

Minor Engine, Six-Cylinder (AJ6/AJ16)

Oil leaks (cam covers and sump)

Symptoms

Oil weeps from the cam cover gaskets and sump gasket. Drips on the exhaust and smokes.

Cause

Gaskets harden with age and heat cycling. The cam cover gaskets are cork or rubber and deteriorate over time.

Fix

Replace the gaskets.

Cam covers are a straightforward job, $200-400 in parts and a couple of hours' work.

Sump gasket requires more access.

Use quality gaskets and don't overtighten.

Cost mentioned in fix

$200-400 in parts

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// More XJ-S problems

Other known issues

Common Engine, Six-Cylinder (AJ6/AJ16)

Timing chain tensioner failure

Rattle from the front of the engine on cold start, which may or may not settle when warm. In severe cases, the chain jumps a tooth and the engine runs badly or stops.

Minor Engine, Six-Cylinder (AJ6/AJ16)

3.6 cylinder liner issues

Coolant loss, white smoke, overheating. The 3.6-litre AJ6 can develop cracks in the cylinder liner sealing.

Minor Engine, V12

Cooling system failure

Engine overheats, temperature gauge climbs into the red, coolant boils over. In severe cases, head gaskets fail and coolant enters the oil.

Common Engine, V12

Head gasket weeping

Coolant appears around the head gasket line (external weep), or coolant contaminates the oil (internal failure, mayonnaise under the filler cap, white exhaust smoke).

Common Engine, V12

Lucas ignition system failure (pre-1989)

Misfiring, rough idle, hard starting, power loss, sometimes total ignition failure.

Common Engine, V12

Marelli ignition issues (1989 onwards)

Similar symptoms to Lucas, misfiring, rough running, but less frequent and usually easier to diagnose.

View all 23 XJ-S problems