Summer Car Problems: How Hot Weather Impacts Your Car

Hot weather can be hard on your car, affecting everything from its tyres to its coolant and making breakdowns more likely. With the Met Office predicting even hotter UK summers than those seen in 2025,¹ ensuring your vehicle is ready before setting off has never been more important.

Nearly a fifth (17%) of UK driving licence holders don’t perform basic safety checks before they go on a long trip.² But just a few pre-journey checks could avoid delays and keep you safe.

In this article, we explain how summer weather affects your car and how to reduce your risk of a breakdown.

Must know

Overheating is a significant but avoidable issue during the summer. Check your coolant is between the minimum and maximum levels before you set off.

In short

Follow the Highways Agency’s T.R.I.P2 advice for long journeys: T – top up your fuel, oil, and screen wash R – rest every two hours I – inspect the tyres P – prepare for the weather

 

Coolant – keep your vehicle cool this summer

A car breaking down is the last thing you want on a summer holiday – but it happens more often than you realise. The BBC reports that around 5,000 breakdowns occur every week in the UK from July to August.³

Higher temperatures increase the chances of breakdowns,⁴ and overheating is often a leading cause. Soaring temperatures due to climate change will understandably add to the strain on cars. In 2025, the fifth-warmest year on record, Faversham in Kent reached a high temperature of 35.8°C.⁵

Air conditioning can help to reduce driver fatigue on long journeys and keep your passengers cool too.

What you can do

Topping up your coolant can help prevent your engine from overheating in the summer.⁶ You should add engine coolant rather than water, as it’s far more efficient and offers better protection.⁵ 

The engine must be cold before you fill the coolant tank. Slowly unscrew the cap and fill the reservoir up to the maximum (MAX) level mark before fitting the cap tightly. Don’t overfill it.

Get the air-con checked, especially if it’s blowing warm air.⁷ Garages get very busy re-gassing units in hot weather, so leave plenty of time to do it before you leave.

Tyres – inspect them before you leave

Summer trips can put your tyres under pressure, risking a blowout,² especially if you don’t take regular long journeys. Then there’s the heavier load – whether it’s additional passengers or a trailer in tow – that can increase tyre wear and affect handling.

What you can do

Before your trip, check that the tread depth is at least 1.6mm and inflate them to the correct pressure.² Look for cracks and bulges that the heat could have worsened, not forgetting to check that the spare tyre has sufficient tread and inflation.

It’s always a good idea to review your vehicle’s manual to adjust the tyre pressure to the recommended level, especially for a heavier load.

If you stop for a break on your journey, try to park in a shady spot to keep the car cool.²

Battery – keep it charged

Hot weather, short trips here and there, and lots of electronic devices being charged on the go all add up to extra strain on the car battery.

In busy summer holiday hotspots, traffic’s stop-start nature can also make it harder for the battery to stay charged on short journeys.³

What you can do

Rather than taking short car trips, save battery power by taking a bus to the beach or town. You could always swap a drive for a walk if the weather’s nice.

You could also visit a garage for a free battery test a few days before you go, giving you time to replace it if it’s weak. You could also charge the battery overnight in readiness for a long journey.

Keeping jump cables in your car means other road users may be able to help, as long as you know how to use them safely. If the battery is flat, roadside assistance can help. Check your policy documents to see if any breakdown cover is included.

Alternator – preventing faults

The alternator keeps the battery charged and powers your car’s electrical systems, such as its lights, air conditioning and instrument panel.⁸ In the summer, especially if you use your car for short journeys, it may struggle to do its job.

What you can do

Preparation can save you time and money. Top up the battery before a summer drive to reduce strain on both the battery and the alternator.

Dimmer-than-usual lights, flickering lights or air-con issues could signal alternator problems.⁷ Get a garage to check the alternator before you go, as faults can be tricky to fix. It might be able to clean, repair or find new parts, so you can keep to your plans without incurring the expense of a replacement.

If you’ve started on your long journey and the battery warning light comes on, find a safe place to stop and call for roadside assistance.

Discover how our Breakdown Cover can get you going.

Pre-trip checks

Planning ahead this summer can reduce the risk of a breakdown, helping you enjoy a fun, stress-free holiday drive.

Here’s a list of pre-trip maintenance checks, whatever the weather:

• Ensure oil levels are not too low or too high
• Clean your lights
• Test the car battery
• Address any warning lights on the dashboard
• Assess your tyres
• Top up screen wash and coolant
• Check your brakes

Should a breakdown occur, be prepared by carrying a warning triangle, a torch and batteries, a mobile phone and charger, drinks, snacks and a warm blanket. Even in the summer, it can turn chilly in the evenings.

Remember to check you have the correct car insurance and breakdown cover.

Find out more about Rias car insurance and breakdown cover.

 

 Sources

[1] https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2025/summer-2025-is-the-warmest-on-record-for-the-uk

[2] https://nationalhighways.co.uk/road-safety/trip/

[3] https://www.bbc.co.uk/programmes/articles/5YQ6mqpHd5wpt6vLHBtH69Z/summer-car-maintenance

[4] https://www.rac.co.uk/drive/news/motoring-news/breakdowns-surge-as-heatwave-sweeps-across-uk/

[5] https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2025/uk-records-fifth-warmest-july-on-record

[6] https://www.national.co.uk/blog/how-to-top-up-engine-coolant

[7] https://www.which.co.uk/news/article/car-experts-reveal-the-7-essential-maintenance-checks-you-must-do-this-summer-alqpw4c5aahg-aLQPW4c5AaHg

[8] https://www.rac.co.uk/drive/advice/car-maintenance/signs-of-a-faulty-alternator-all-you-need-to-know/