Chassis and box sections can rust. Also check for accident repairs
Front hub sensors. Each wheel’s rotation is electronically monitored by a sensor, which can fail regularly on earlier vehicles
Leaking sunroof. Debris block drain holes, then water comes in
Wet rear load space. Water gets in above the rear door
Air suspension. Is it sitting level? Does the air compressor come on at start-up? Could be a leak at the bottom of the suspension air bag
Smoke. Look for blue oil smoke, black diesel smoke (overfueling), heavy black diesel smoke (failing turbocharger) or white smoke on starting (water in the bores)
Steering bushes wear rapidly
Coolant leaks. Td5 water pumps can leak, causing coolant level to drop, then overheating occurs
ACE (Active Cornering Enhancement) pipes are showing corrosion on early models. Can be seen behind the off-side front wheel
Interior and exterior. Most should still be smart. Tatty or battered examples should be very cheap – but better to find another than repair/repaint. If interior looks worn is the mileage higher than indicated?