Car Breakdowns Jump a Fifth as a Rare Red Heat Warning Hits UK Roads

The blast of summer heat gripping Britain this week is doing more than disrupting sleep and melting ice creams. It is pushing thousands of cars to breaking point. The RAC says its roadside patrols dealt with a fifth more breakdowns than is normal for late June as temperatures soared, and with the Met Office issuing a rare red warning for extreme heat, drivers are being urged to think carefully before getting behind the wheel.

If your car is showing a warning light, running on tyres that have seen better days, or relying on a battery that is several years old, the next few days are exactly when those weak points tend to turn into a roadside emergency. Here is what is happening on the roads, why high temperatures are so hard on vehicles, and the simple checks that can keep you moving while the heat lasts.

Why a Heatwave Sends Breakdowns Soaring

The RAC reported that its patrols handled a fifth more breakdowns on Wednesday 24 June than would be typical for the time of year, with the biggest jumps recorded in London, Essex, Kent and Sussex. The day before had already been busy, with breakdown numbers running around 20 per cent above normal for late June. The organisation had warned at the start of the week that demand for help would climb by roughly 10 per cent compared with a usual mid-June day, and the reality has matched that forecast.

The pressure on the roads has come as the Met Office issued a red warning for extreme heat covering Wednesday 25 and Thursday 26 June, the most serious category of alert it can give. Forecasters expected temperatures to push past 37C in the shade across parts of England and Wales, with some spots reaching as high as 40C. A red warning is reserved for conditions that pose a risk to life and to everyday services, and breakdown cover is one of the many things that comes under strain when the mercury climbs this high.

RAC road safety spokesperson Rod Dennis said the situation was serious enough that drivers should weigh up whether their journey was needed at all. “As much of the country endures a further day of extreme heat, we cannot emphasise enough the dangers of breaking down in these conditions,” he said. “Anyone who can delay non-essential trips until the weather starts to cool should do so.” He added that patrols were stretched and asked drivers to be patient, noting that “these are exceptional times with many vital services affected by the fierceness of the summer heat.”

So serious is the risk of being stranded in the sun that RAC patrols have been carrying extra bottles of water to hand to broken-down members. Breakdown spokesperson Simon Williams put it bluntly earlier in the week, warning that “breaking down in these conditions is potentially life threatening if they aren’t properly prepared. Being stuck at the side of a hot road without enough water and some form of shade is very serious.” For elderly, very young or vulnerable passengers, a long wait on an exposed verge in 38C heat can quickly become a medical problem rather than just an inconvenience.

The Three Faults Most Likely to Strand You

According to the RAC, three problems sit at the top of the list during hot spells, and all three are made worse by high temperatures rather than caused by anything the driver has done wrong on the day.

Tyre blowouts are the first. As the air inside a tyre warms it expands, raising the pressure. A tyre that is already worn, damaged or incorrectly inflated has far less margin to cope, and a sudden failure at speed on a motorway is both frightening and dangerous. The RAC’s mobile mechanic of the year, Jack Halstead, singled out “overheating engines and tyre blowouts, caused by air expanding in the heat” as the faults topping the call-out list this week. Hot, abrasive road surfaces add to the strain, which is why tyre condition deserves a proper look before any long trip in this weather.

Batteries are the second. It is a common myth that car batteries only fail in winter. Heat actually accelerates the chemical wear inside a battery and can cause the fluid to evaporate, leaving a unit that was coping fine in spring suddenly unable to turn the engine over. A battery that is more than three or four years old is the most likely to give up, often without much warning, and a flat battery is one of the single most common reasons drivers find themselves waiting at the roadside.

Overheating engines are the third. Cooling systems have to work far harder when the outside air is already close to 40C, and any existing weakness, a low coolant level, a tired water pump, a slow leak or a failing radiator fan, is much more likely to tip over into a full breakdown. The warning signs include the temperature gauge creeping up, steam from under the bonnet, or an unusual smell. If any of those appear, the safest move is to pull over where it is safe to do so, switch off the engine and let it cool rather than pressing on.

The Checks to Do Before You Turn the Key

A few minutes of preparation can be the difference between a smooth journey and a long, hot wait on the hard shoulder. The RAC and the AA both recommend the same core checks during a heatwave.

Start with the tyres. Check the pressures against the figures in your handbook or the sticker inside the driver’s door, and always check them when the tyres are cold rather than after a drive, because a warm tyre will give a falsely high reading. Look closely at the tread and the sidewalls for cracks, bulges or embedded objects, and do not forget the spare if you carry one. Then lift the bonnet and check the coolant and oil levels, topping up if needed once the engine is cold. Glance over the engine bay for any obvious leaks or perished hoses.

Pay attention to your dashboard. The RAC has been firm that a car already showing a warning light should not be driven in this weather until it has been looked at. “Drivers whose vehicles have pre-existing problems like a warning light on the dashboard must get these checked by an RAC mobile mechanic or reputable garage before attempting to set out,” Rod Dennis said. “Running the gauntlet is never a good idea, but especially so in this weather.”

Then pack for the worst case. Carry at least one litre of water per person, plus a spare bottle or two, because dehydration and fatigue set in quickly even in a healthy adult. Take suncream, an umbrella or something else that can block the sun if you end up waiting at the roadside, and bring a phone charger and a portable battery pack so you can always call for help. The RAC also advises shielding your phone from direct sunlight, since a handset that overheats and shuts down at the wrong moment leaves you with no way to reach assistance.

Why Sitting With the Engine Running Could Cost You

One temptation in extreme heat is to sit in a parked car with the engine running so the air conditioning keeps things cool. The RAC has warned that this habit can have costly consequences, and not only at the fuel pump. Leaving an engine idling unnecessarily while stationary on a public road is against the Highway Code, which states under Rule 123 that drivers must not leave a vehicle’s engine running needlessly while parked.

Enforcement sits with local councils under the Road Traffic (Vehicle Emissions) (Fixed Penalty) (England) Regulations. A driver who refuses to switch off when asked can be issued a fixed penalty of 20 pounds, which doubles to 40 pounds if it is not paid within the set period, and some authorities are pushing for tougher action as air quality concerns grow. Beyond any fine, prolonged idling burns fuel for no distance covered and adds avoidable wear, so the cheaper and cooler option is usually to park in the shade, open the windows and wait, or to plan the trip for a cooler part of the day.

How Long the Heat Will Last

The Met Office expected the most intense heat to ease after Thursday, with fresher conditions and the risk of thunderstorms following the peak. That should bring breakdown numbers back towards normal, but the lesson of this week is one that holds for the rest of the summer. Britain has now seen several summers of record-breaking temperatures, including July 2022 when the mercury topped 40C for the first time on record and breakdown organisations reported some of their busiest days ever. Each of those spells produces the same surge in heat-related failures.

The practical takeaway is to treat hot weather with the same respect drivers normally reserve for ice and snow. If you can travel early in the morning or later in the evening when it is cooler, both you and your car will have an easier time of it. Build in extra time, keep water in the boot as a matter of routine through the summer, and deal with that nagging warning light or ageing battery before it deals with you. A short visit to a garage or a mobile mechanic now is far cheaper than a ruined day and a recovery truck later.

Sources:

• https://media.rac.co.uk/rac-reaction-breakdowns-up-by-a-fifth-during-heatwave
• https://media.rac.co.uk/breakdowns-20-up-during-heatwave
• https://media.rac.co.uk/rac-warns-of-early-summer-surge-in-breakdowns-with-arrival-of-next-heatwave
• https://www.rac.co.uk/drive/news/motoring-news/heatwave-uk-car-checks/
• https://www.theaa.com/about-us/newsroom/drivers-warned-heatwave-risks-continue-into-the-working-week