First inspect the engine, turbocharger, injectors, transmission, differential and 4WD system.
Then inspect the chassis, suspension, leaf springs, steering, brakes and underbody.
Look for accident repairs, chassis welding, rust, flood damage and signs of hard off-road use.
Check the auction/import history where available, verify mileage and inspect the AC, electrical systems, infotainment, camera, tyres and wheel alignment.
A test drive should include cold starting, acceleration, braking, gear changes, steering response and 4WD operation.
On a used Hilux, a professional mechanical inspection can save a very large repair bill.