A fifteen-minute test drive, done properly

You will rarely get an hour. Fifteen minutes is enough if you spend them deliberately.

Before you move

• Start it from cold if you can. Ask the seller not to warm it up before you arrive — a lot of problems only show on a cold start, and a seller who insists on having it running is telling you something.
• Radio off, windows down, air conditioning off. You are listening.
• Check the dashboard lights come on and then go out. One that never comes on has been removed.

The first five minutes

• Full steering lock both ways at walking pace, windows down. Clicking or knocking is a joint.
• Brake firmly once, from about 40, on a clear road. The car should stop straight and without shuddering.
• Find a rough patch deliberately. Suspension is cheap to fix and expensive to ignore.

The next five

• Get it into every gear, including reverse. On a manual, hold third and lift off — a worn clutch shows as revs climbing without speed.
• On an automatic, feel for a shift that thumps or hunts between two gears.
• Let it idle at a light for a minute with the air conditioning on. Temperature should stay put.

The last five, stationary

• Bonnet up while hot. Look for wet patches, not just drips.
• Electrics: every window, the indicators, the horn, the reverse camera if it claims one.
• Look underneath at where you parked. A fresh stain is a leak.

What to do with what you find

Almost nothing on a used car is a dealbreaker on its own — it is a price. Note what you found, get a rough cost for it, and put that number on the table instead of walking away from a car that was otherwise right.