Buyer beware…

ENGINE

Engine warning light on four-pot Z3 could be a failed lambda sensor; rough running on post-2000 six-pots with VANOS could be the camshaft position sensor. Listen for dual-mass flywheel rattles and for a six-pot engine tapping on start-up (an oil change might cure it). Anything louder could be drive belt tensioners. New starter motors on four-pot engines are expensive.

COOLING SYSTEM

Thermostats last around 60k miles but stick in the open position. Check its housing, the radiator and the top hose connection for leaks. Listen for water pump noises; replacement is easiest on six-cylinder cars. Fan coupling lasts 80k miles or so. Check oil for coolant.

TRANSMISSION

A sticky manual on 2.8s may require fresh oil. On all manuals, feel for clutch drag. Check an auto has had fresh fluid; check rear diff mount’s condition.

SUSPENSION AND STEERING

Check front and rear anti-roll bar drop links, and front lower ball joints and inner bushes. Dampers fail at around 80k miles, so aftermarket Bilsteins with Eibach springs are common. Check the variable steering pump for leaks.

BODY

Check door bottoms and boot lock for rust and fuel tank for damage. Look for a cracked rear window and worn roof seals. Check powered hood operation (top controller modules play up).

INTERIOR

Airbag warning light is probably a faulty seatbelt receiver. Knocks and rattles could be failing rear suspension top mounts.