Car problems: warning lights, noises and leaks explained

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What drivers say about mechanics in our network

4.8from 797 Google reviews of the workshops in our network, checked Nov 2026

Roadworthy certificate

We got our RWC done here and were very happy with the service. The process was smooth, professional, and completed in a timely manner. The team was friendly, helpful, and explained everything clearly. Would definitely recommend.

Priti G., Jun 2026

Google review of a workshop in the Mechanic Sorted network, 4.7 stars from 323 reviews.

Repair work, quoted before starting

Quick drop off. Told what needed doing and how much before the work commenced which was very appreciated. Car ready on time. Great service and car runs like a dream. Thanks guys.

Jayson M., May 2026

Google review of a workshop in the Mechanic Sorted network, 4.7 stars from 323 reviews.

How to read what the car is telling you

Orange or yellow lights on the dash usually mean have it looked at soon. Red lights usually mean stop somewhere safe and switch off. A light that flashes is more urgent than one that stays on.

Noises and smells don't come with a colour, so go by how the car feels. If the brakes feel different, the steering pulls or something smells hot, treat it as urgent and don't wait for the next service.

Each page below says what to check, what the mechanic will do first and whether it can wait.

Warning lights, noises and leaks

Engine light onSteady or flashing, what the engine light usually means, and what the mechanic checks first.White smoke from exhaustWhite, blue or black: what exhaust smoke usually means, and which colour says stop.Car won't startClick, slow crank or silence: what each one points to when the car won't turn over.Car leaking oilHow to read the drip, which seal it usually is, and when an oil leak can't wait.Stopping a radiator leakHow to spot a coolant leak, why it can't wait, and what the lasting repair involves.Blown head gasketOverheating, milky oil, vanishing coolant: head gasket symptoms and what else looks the same.Squeaky brakesDamp morning squeak or worn pads: what a brake squeal usually means and how soon to act.How to fix an overheating carTemperature light on or gauge climbing: what to do first and what's usually behind it.Car wiggling or shakingIdle shake, highway shake or wobble: what each one points to and how urgent it is.Transmission fluid leak: the fix, and what to do firstA red trail under the car: why not to drive on it, and what the repair usually involves.Car noisy? What the sound meansSqueak, clunk, rattle or whine: what the noise usually is and which ones can't wait.CV joint noise and other noises when turningClick, clunk, squeal or groan on a turn: what each noise usually points to and how soon to act.Engine misfire or rough idleWhy an engine stumbles or idles rough, when to stop, and how a mechanic proves the cause.Power steering fluid leakHow to tell it's power steering fluid, why top-ups don't fix it, and what the mechanic replaces.Braking and your car shakes: brake shudderWhy the wheel or pedal shakes under braking, what's urgent, and what a mechanic should measure.Battery light onWhy the battery light usually means charging trouble, what to do first, and what gets tested.Wheel bearing noise: humming or whiningHow to tell a worn wheel bearing from tyre, diff or alternator noise, and how soon to act.Car battery dead or flatHow to get going with a dead battery, and how to tell an old battery from a charging fault.Engine knocking or tickingKnock, ping or tick: how to tell them apart and which one means switch off now.Clutch slipping or gearbox slippingWhat slipping feels like on a manual, auto or CVT, how far to drive, and what gets checked.Car in limp modeWhy a car cuts its own power, how to restart it safely, and what the mechanic reads next.Low oil pressure warning lightRed oil can on the dash? Why it means stop, what to check once it's cool, and what comes next.Fix a brake fluid leak: a mechanic's job, not a top-upWhy a top-up won't fix a brake fluid leak, where leaks start, and what makes the job bigger or smaller.DPF warning lightWhy a diesel's DPF light comes on, the drive that can clear it, and when it needs a mechanic.Clunking noise or rattle in the carClunks and rattles sorted by when they happen, how urgent each one is, and what the mechanic looks at.Traction control lightWhat a flashing or stuck traction control light means, and why it often comes on with the engine light.Grinding noise when brakingWhy brakes grind, how to tell it from a squeal or surface rust, and what a mechanic will measure.Brake warning light or ABS light onRed brake light or amber ABS light: which one means stop, what to check, and what the mechanic looks for.Belt in car squeaking or squealingWhy a belt squeaks, what the timing of the noise tells you, and when a squeal becomes urgent.Airbag light onWhat an airbag light means, why it matters when the car feels fine, and what the mechanic reads.

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