Five reasons why cars break down (and how to avoid them)

It may be the most wonderful time of the year, but unfortunately, winter’s the peak time for car breakdowns.

Many cars suffer similar issues, which means we know what to expect and can help you do something about it.

Here we look at the top reasons why cars break down and some tips you can follow to keep yours on the road.   

Flat or faulty battery

Batteries are the number one reason why cars break down. Nearly one third (32%) of Green Flag’s callouts are down to battery issues.

Your car battery can get drained by short trips, cold weather, or leaving your lights on – things that happen regularly during winter!

What to do about it.

The good news is, you can take a few simple steps to help keep your battery ticking over:

  • Turn off all your lights and electrics when you get out of your car
  • Take a longer drive (20-30 minutes) once a week
  • Regularly clean the battery terminals and check the connections (if you feel comfortable doing so)
  • Consider replacing your car battery every 3-5 years

Another way to keep your battery in check is to get a trickle charger. It can help stop your battery going flat, even if you haven’t driven your car for a while.

Tyres

If your tyres aren’t in good condition, your chances of a break down increase at this time of year.

Low pressure and worn tread can be really dangerous when the roads are wet or icy because your tyres can’t grip the road surface properly.

In fact, worn tyres can increase your stopping distance by almost 50% in wet conditions.

What to do about it.

Making sure your tyres are up to the job is important all year round, not just in winter. Here’s what you can do:

  • Do the 20p test to check your tyre tread – insert the coin into one of the tyre’s grooves, and if you can see any of the outer band of the coin, your tyres may need replacing.
  • Check your car’s handbook to find out the correct pressure for your tyres and make sure they’re inflated to that level.
  • Make sure you’ve got a spare tyre and the tools you need to fit it, in case you get a puncture when you’re on the road.

Alternator and electrical failures

If your car’s alternator is faulty, it can stop the battery from recharging. This can lead to problems with the electrical systems affecting your lights, sound system, and heated seats (if you’re lucky enough to have them).

If you don’t have a functioning alternator, you could break down and end up stranded with a dead battery.

What to do about it.

Keep an eye out for these signs that your alternator isn’t working properly (so you can get it sorted before it becomes a problem):

  • Look for flickering lights, slow window wipers, or dashboard warning symbols.
  • You might have trouble starting your car, including clicking or cranking noises when you turn the ignition.
  • The electric windows might become sluggish when you open and close them.

If you notice any of these signs, it’s worth getting your car checked over to see if your alternator needs replacing.

Overheating engine

An overheating engine can be dangerous, and if you think it’s happening to your car, you should pull over straight away.

The most common causes of car engines overheating are low coolant levels, a fault with the cooling system, or low engine oil caused by a leak.

It’s always a good idea to get your car checked over if you suspect the engine is overheating because it could be a sign that there’s a more serious problem.

What to do about it.

Although overheating engines can sometimes be down to things out of your control, there are some steps you can take to lower the chances of it happening:

  • Keep your coolant levels filled up and carry extra with you in case you need it
  • Check your oil levels regularly and top them up before long journeys
  • Get your cooling system flushed out and cleaned every 40,000 miles

Remember, continuing to drive with an overheating engine can cause lasting damage. Don’t risk it.

Misfuelling

Misfuelling, or putting the wrong kind of fuel in your car, sounds like something you’d never do, but it’s surprisingly common.

In fact, around 150,000 people in the UK fill up with the wrong fuel every year.

It’s an easy mistake to make, but it can not only lead to a break down, it can cause a some serious damage to your engine.

What to do about it.

OK, the obvious answer is don’t put the wrong fuel in your car. But, there are some practical steps you can take to make sure you don’t get caught out:

  • If you’ve got a new car, be mindful of the type of fuel it uses in case it’s different to your last set of wheels.
  • Avoid distractions when you’re filling up – focus on the job at hand.
  • If you’ve got a diesel car, you can get a special fuel cap that stops petrol nozzles fitting the tank – they cost around £30, much less than a new engine!

If the worst happens and you do misfuel, don’t start your engine, just get in touch with Green Flag.

37 comments on “Five reasons why cars break down (and how to avoid them)

  1. Barbara Mitchell 11/01/2026 10:39 AM

    Brilliant advice. Thank you. I’m going out to do relevant checks now then go for a drive.

  2. Stephen 11/01/2026 10:42 AM

    Thank you for the Advice and tips I will definitely keep an eye out for any problem’s I’ve just had my car serviced so hopefully it should be OK but one of the things is keeping your windscreen washer bottle full or topped up .

  3. Chris R 11/01/2026 11:10 AM

    Thanks for the article. Useful and timely info.

  4. Brian Davies 11/01/2026 11:30 AM

    thanks for all the information I found it very informative.

  5. WINSTON DYER 11/01/2026 11:48 AM

    GOOD ADVICE

  6. Gordon Bennington 11/01/2026 11:50 AM

    All very sound advice. Taken on board and will be followed

  7. T Lewins 11/01/2026 12:42 PM

    Excellent piece

  8. Janita Goodwin 11/01/2026 12:43 PM

    thank you for all your helpful advise as to what to do when there is trouble.
    I found it all very reassuring.

  9. Harry.jack1@sky.com 11/01/2026 1:28 PM

    Thanks for the information

  10. Ian Salisbury 11/01/2026 1:33 PM

    I have a electric car, what could be the problems

  11. Danny Loughran 11/01/2026 1:37 PM

    Great advice many thanks

  12. Raymond Hunt 11/01/2026 1:46 PM

    Good sound advice, especially the trickle charger

  13. Roopsen Gunnoo 11/01/2026 2:15 PM

    Great advice. Thanks.

  14. Stanley Turner 11/01/2026 2:30 PM

    Thankyou for all your advice

  15. STANLEY TURNER 11/01/2026 2:31 PM

    Thankyou for your advice

  16. Derek 11/01/2026 2:50 PM

    Very good comments given in this email

  17. Chris Roberts 11/01/2026 2:51 PM

    Thankyou for a sensible and informative article.

  18. Cynthia Wood 11/01/2026 4:00 PM

    Exadvice – thank you

  19. Martin Wells 11/01/2026 4:04 PM

    Thank you. Some very useful tips.

  20. David Rogers 11/01/2026 4:54 PM

    Really good tips on winter driving.

  21. R Abbott 11/01/2026 6:26 PM

    Great tips thank you

  22. Anthony Schwab 11/01/2026 6:51 PM

    Greenflag recently came to our rescue when my wife’s car refused to start.
    It turned out to be a flat battery caused by a loose terminal connection which the Greenflag mechanic quickly sorted out!

  23. John Fisher 11/01/2026 7:24 PM

    Excellent info

  24. Ann Kibble 11/01/2026 8:17 PM

    What are cooling levels and what should be carried in the car?

  25. Mackenzie 11/01/2026 10:46 PM

    Thanks for the heads up

  26. Robert Newlands 12/01/2026 1:30 AM

    I always have an extended drive once a week, I used to be an Auto Electrician, sound advice from you.

  27. M. Barnes 12/01/2026 7:49 AM

    Very helpful information. Thank you

  28. M Barnes 12/01/2026 7:51 AM

    Very useful information. Thank you

  29. Robertson 12/01/2026 3:25 PM

    Thank you – have taken it all in!!!!

  30. Maurice Johnson 12/01/2026 5:06 PM

    All sensible and simple advice – and don’t forget that a spell of cold weather can cause a drop in tyre pressure of 10% or more

  31. Catherine 12/01/2026 5:11 PM

    Just what one needs. Thank you

  32. Lynn 13/01/2026 8:01 AM

    Great info thanks

  33. Christine Pockett 13/01/2026 9:40 AM

    Very helpful indeed. As a mature motorist I really appreciate it.

  34. Gill 14/01/2026 8:33 AM

    Really good advice! I always read the Green Flag newsletter.

  35. John Burton 14/01/2026 4:45 PM

    Excellent advice. My battery failed some years ago in February in a car park in Exmoor. It was about 7 years old but as their were no symptoms of imminent failure (difficult starting, dimming headlights) I hadn’t bothered to replace it. Big mistake long cold wait for recovery (not Green Flag).

  36. Jenny 16/01/2026 10:42 PM

    Very useful information to know what to do.
    Thankyou

  37. Ed perry 19/01/2026 3:31 PM

    Sound advice always take it , great company to be with.

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