1. Oil Warning Light or Low Oil Level
The oil warning light (an oil can symbol) appearing on your dashboard is a serious warning — stop the car as soon as it's safe and check the oil level immediately. Running an engine with critically low oil pressure can destroy it within minutes.
Even without a warning light, check your oil level monthly. If it's consistently low, you may have a leak or your engine is burning oil — both need investigating.
2. Engine Warning Light
The engine management light (EML) covers a wide range of faults. A steady amber light means book a diagnostic check soon. A flashing light indicates a misfire — stop driving at high revs and book a garage immediately to avoid damaging the catalytic converter.
3. Unusual Noises
- Knocking from the engine — low oil, worn bearings, or piston issues
- Squealing when braking — brake pad wear indicators — pads need replacing soon
- Grinding when braking — pads worn through, metal on metal — dangerous, stop driving
- Rattling from underneath — loose exhaust, heat shield, or suspension component
- Clicking when turning — worn CV joint, common on front-wheel-drive cars
4. Increased Fuel Consumption
A noticeable drop in mpg without any change in your driving or route can indicate worn spark plugs, a dirty air filter, a failing oxygen sensor, or low tyre pressure. All are service items. If your fuel consumption has increased by more than 10–15%, it's worth investigating.
5. Difficulty Starting
A slow, laboured start suggests a weak battery (particularly noticeable in cold weather) or worn spark plugs. A battery that struggles to start the car on a cold morning typically has less than a year of reliable life left.
6. Vibration or Pulling
- Car pulling to one side — uneven tyre pressure, worn tyre, or wheel alignment issue
- Vibration through the steering wheel at speed — wheel balance or alignment
- Vibration through the brake pedal — warped discs
7. Burning Smells
- Burning oil — oil leak dripping onto hot components
- Burning rubber — slipping belt, or a brake sticking
- Sweet smell — coolant leak; don't ignore this — overheating can cause head gasket failure
8. Service Interval Exceeded
The most straightforward sign: your dashboard service reminder light is on, or you've gone more than 12 months or 12,000 miles since the last service. Don't ignore these — engines run on oil, and old, degraded oil causes wear that accumulates silently until something fails.
How Long Can You Leave a Service?
Manufacturers set service intervals as a maximum, not a target to hit on the nose. Extending beyond the recommended interval increases wear and can void warranty coverage. It also means any borderline safety items (brake pads, tyres) go unchecked for longer. Book when the reminder says, not when the car tells you it's struggling.