Top 10 most common causes of car breakdowns

Article contents


Car breakdowns are rare, but the chances are higher during the winter months.

We’ve analysed internal data to compile a list of the most common reasons for vehicle breakdowns. We also cover what to do if you do breakdown and how to avoid a breakdown.

What to do if you break down

If you break down on the motorway, follow Highways England’s five tips:

  1. leave the motorway if possible: get to an emergency area or the hard shoulder and use the nearest free phone
  2. if you can’t do the above move onto the verge
  3. get out of the left side of your car and get behind the barrier if it’s safe
  4. call your breakdown provider or Highways England on 0300 123 5000
  5. if you break down in moving traffic and can’t leave your car, keep your seatbelt and hazard lights on and call 999

If you're an Admiral customer, call our customer services team to discuss the different levels of cover we offer. Your cover will start 48 hours later. Or you can buy our Breakdown Cover when you get your car insurance quote.

1. Battery

Battery failure is caused by a variety of reasons including:

  • a loose terminal connection
  • battery fault
  • leaving your lights on
  • old age
  • leaving your car unused
  • only making short journeys
  • a problem with the alternator

Most car batteries have a guarantee of 3 to 5 years, so if you have an old battery and it’s starting to struggle, replace it before it lets you down.

2. Tyres

Punctures can be caused by hitting a pothole or kerb, running over a sharp object like a nail or screw, a faulty valve or simply a worn tyre tread.

The best way to avoid tyre failure is to check the pressures and tread condition of each tyre regularly and don't ignore the tyre pressure warning light if it appears on your dashboard.

You should always have a correctly inflated spare tyre (full size or space saver), but if that's not possible, make sure you have an emergency puncture repair kit which has an aerosol containing a foam that re-inflates the tyre and acts as a sealant.

Preferably, choose one with a water-based foam that can be flushed out after use and doesn't damage the tyre.

3. Engine and exhaust

Your engine can have wide-ranging reasons for a car breakdown including:

  • blown head gasket
  • timing belt
  • oil pump failure
  • oil leaks
  • ageing spark plugs
  • faulty fuel and ignition systems

There may also be issues with your exhaust system, such as:

  • corrosion
  • cracks
  • broken brackets
  • increased levels of pollutant gases

Additionally, the catalytic converter, or CAT, forms part of the exhaust system. Its responsible for cleaning up the harmful gases emitted from your engine before they can escape through your exhaust pipe.

To avoid engine or exhaust failure, keep up with routine maintenance jobs and stick to your car's service schedule (usually a full service every year).

4. Electrical

Electrical problems can be some of the most frustrating reasons for a vehicle breakdown because the reason isn't always obvious.

Often, cars must go to a garage where mechanics can carry out a fault diagnosis by hooking up to the car's onboard computer (the electronic control unit, or ECU) and read error codes.

Electrical problems can range from something as a simple as an interior or exterior bulb failure, to worn out spark plugs, or a faulty starter motor or ECU.

Avoid electric problems slowing you down by acknowledging your dashboard warning lights. If you're unsure what a light means, pull over when it's safe to do so and check your owner's manual. If it's serious, seek immediate help from your breakdown provider or a garage.     

5. Steering, suspension and brakes

Steering defects include issues with power steering units (including fluid leaks), plus worn components in the steering rack.

Faulty dampers, or shock absorbers, are one of the most common failures in a car's suspension system. Sometimes it's just wear and tear, however, it's also possible that the fluid has started to seep out.

Brakes are another crucial car component. Ignoring any problems can have serious consequences, putting you and other road users and pedestrians at risk.

Warning signs includes:

  • brakes pedals that feel soft, spongy or offer no resistance
  • your car pulling to one side
  • feeling a vibration through the steering wheel

The problem could be anything from worn pads or discs, or a fluid leak from the master cylinder. Whatever the problem, get expert advice.

Your brakes are checked during your car’s annual service and MOT. However, some garages and tyre-fitting chains will also carry out free brake checks.

6. Fuel

Accidentally filling up your car with the wrong fuel is more common than you might think, affecting an estimated 150,000 motorists every year.

Running out of fuel is another common reason for roadside rescues.

Other fuel-related faults which can cause a breakdown include problems with:

  • fuel pump
  • throttle assembly
  • blocked fuel injectors and filters

If you misfuel your car, realise before starting your engine, leave the engine switched off (don't even put your key in the ignition) and inform the staff at the service station.

7. Clutch

If you drive a manual car, a clutch can wear out or the system may develop a leak. A clutch should last anywhere between 60,000 to 80,000 miles.

Clutch components include the clutch plate, pressure plate, flywheel, slave cylinder and clutch cable.

Warning signs include:

  • a clutch pedal that feels spongy or makes an unusual noise
  • poor acceleration
  • difficulty shifting gears
  • 'slipping' clutch which causes a momentary loss of acceleration

Never 'ride the clutch'. In other words, don't keep the clutch pedal partially pressed down because it pushes the pressure pad against the clutch plate but doesn't engage completely, creating more friction and wearing out the clutch faster.

Instead, keep your foot well away from the clutch unless you are actually changing gear. Don’t slow down for traffic lights with the clutch semi-depressed and don't treat your clutch pedal like a footrest.

8. Alarms, locks and keys

If you're having issues with the car alarm, try your second fob (if you have one). If this works, you just need to change the battery in your fob.

If neither work, there may be a fault with the fobs (you need a new one) or an electrical problem with a sensor, in which case you should get professional help.

Other issues include:

  • keys locked inside vehicles
  • broken keys
  • keys stuck in ignitions
  • jammed steering locks

If possible, avoid buying a new key from a main dealer (it could cost as much as £150-£300). Instead, get a replacement from a key cutter like Timpson, or get a quote from a mobile auto locksmith.

9. Charging

An alternator can go at any time.

Signs that all might not be well include:

  • dashboard warning light
  • flickering headlights
  • a grinding, clanking or screeching noise coming from your engine bay

Related alternator components include the drive belt, the pulley and the battery warning light which warns you when the alternator is not charging the battery.

10. Cooling

You might notice your temperature warning light go on or, worse still, steam coming out of your engine bay.

Either way, pull over in the nearest safe spot, turn off your engine, get all passengers away from the car and road, and call for breakdown assistance.

If you're more confident mechanically:

  1. open the bonnet (it may be hot) and leave the engine to cool down for 30 minutes or longer
  2. once fully cooled carefully check the coolant
  3. never unscrew the radiator/coolant tank cap of an overheated engine, it's pressurised and could cause severe burns
  4. if there's no coolant you probably have a leak (possibly in the radiator or a hose) and there may be a pool of liquid underneath your car
  5. other reasons for an overheating car including a faulty thermostat, cooling fan or water pump

We also have a handy guide on how to to check your engine's coolant.

Avoid overheating by regularly checking and topping up the coolant. Also make sure the cooling fan is operating — you can hear it after a journey. Also look under your car now again to check for any leaks.

I'm an experienced journalist, digital editor and copywriter, now specialising in motoring. I’m editor of Automotive Blog and have worked across the media in newspapers, magazines, TV, teletext, radio and online for household names including the BBC, GMTV, ITV and MSN. I’ve produced digital content in the financial sector for Lloyds Bank, Nationwide and the Money Advice Service. I'm married with two children and live near Bath in Somerset.

Great car insurance options for the whole family