What the noise, the light or the smell is telling you.
35 guides in Motoring
How to tell a harmless morning squeal from a worn-pad squeal from metal-on-metal, what a soft or long pedal is telling you, and the three symptoms that mean stop rather than book it in.
Working out from what the car does when you turn the key whether it is the battery, the fuel, the immobiliser or something that needs a garage.
The colour code that tells you how urgent a light is, the handful of red lights that mean stop now, and how to tell a fault from a reminder.
The signs that a battery is on its way out rather than just flat, how to tell a battery fault from a charging fault, and why the first cold morning is when most of them fail.
What the temperature gauge climbing actually means, the one thing to do immediately, and how to tell a top-up-and-carry-on from a stop-and-call-recovery.
What the red battery symbol is actually reporting, why it is a charging fault rather than a battery fault, and how to tell an alternator from a belt from a battery.
Noises are identified by what makes them change, not by how they sound. A structured way to work out whether a knock, whine, click or rumble is speed-related, engine-related, brake-related or suspension-related.
A smell-by-smell guide to what a car is telling you, which smells are normal on a new or recently serviced car, and the four that mean stop the vehicle immediately.
Telling short journeys and a parasitic drain apart from a battery at the end of its life, and what actually recharges a battery properly.
How to tell a misfire from a fuel supply problem from a clutch or gearbox fault, what the flashing engine light changes, and the cheap causes worth checking before the expensive ones.
Most cars that stop blowing cold have simply lost refrigerant slowly over years. The checks you can do yourself, the ones you cannot, and why the DIY cans are a false economy.
A diesel particulate filter catches soot and periodically burns it off. Why short journeys break that cycle, what the warning light is actually asking you to do, and when it becomes a workshop job.
How to tell water from oil from coolant from brake fluid by colour, position and feel, and which of them mean stop driving now.
What the ABS, traction control and stability control lights actually mean, why one failed sensor takes all three out at once, and the combination that means stop driving.
Road camber, tyre pressures, a dragging brake and misaligned tracking all feel similar from the driver's seat. How to tell them apart before paying for an alignment you may not need.
Torque converter, dual clutch, CVT and automated manual — how each one behaves, what tends to go wrong with each, and what to look for on a test drive.
The four symptoms that actually indicate a failed head gasket, how to tell each from the harmless thing it is confused with, and why continuing to drive is the expensive mistake.
How to separate an engine that is running badly from mountings that are worn, using tests you can do from the driver's seat in a minute.
What forced induction actually does, why oil supply is the thing that kills turbochargers, and what the symptoms of a failing one feel like.
White, blue and black exhaust smoke each point at a different system. How to tell harmless cold-morning vapour from coolant, oil or fuel, and which needs a garage this week.
The bounce test and what it really tells you, how worn dampers show up in braking and tyre wear long before they leak, and why a broken coil spring is the one that means stop.
Why a hard pedal is not a failed pedal, the order of things to try, how to use the gearbox and the parking brake to slow a car, and what actually stops it.
Why a car suddenly refuses to rev, holds one gear or feels gutless, what the engine management is protecting, and how to decide between driving home and stopping.
Why the glass is usually the problem rather than the blades, cleaning off the oily film properly, and the checks that identify a bent arm.