Drivers are being urged to perform a five-minute air conditioning check or risk facing repairs costing up to £800, as the UK braces for another weekend of hot weather. Temperatures are forecast to reach 25C this weekend, according to the Met Office, following England’s hottest June on record, which saw an average temperature of 17.1C – 3C above the long-term average.
Five Common Heat-Related Car Faults
Scott Greensmith, car expert at ClickMechanic, a service that sends mobile mechanics directly to customers' driveways, has highlighted five faults most likely to cause problems in extreme heat. He warns that many can be spotted with a quick pre-journey check, potentially saving drivers hundreds of pounds.
1. Coolant
“Coolant stops your engine from overheating – and in temperatures like these, it's working flat out,” Greensmith said. “A lot of drivers don't check it until a warning light comes on, but by then you're already in trouble.” He advises never opening the reservoir cap while the engine is hot, as this can cause serious injury. If the engine overheats and the head gasket fails, repair costs can range from £600 to £1,500 or more, all because the coolant level wasn't topped up.
2. Tyres
“Heat makes tyre pressure worse,” Greensmith explained. “The air inside your tyres expands as temperatures rise, pushing pressure beyond safe levels – and on a motorway that can mean a blowout.” He recommends checking tyre pressure when the tyres are cold, before driving. A blowout can destroy a tyre instantly, costing between £50 and £250+ to replace, and may also cause damage to the wheel and bodywork, leading to an even larger bill.
3. Battery
“The battery starts your car and powers everything electrical in it – and heat kills it faster than cold weather does,” Greensmith said. High temperatures cause the fluid inside the battery to evaporate and accelerate corrosion, significantly shortening its life. A replacement typically costs between £100 and £300, but if a breakdown occurs on a motorway and a callout is needed, the total cost increases substantially. He advises getting the battery tested before setting off if it is over three years old.
4. Oil
“Engine oil keeps all the moving parts in your engine lubricated and protected – and it thins out in extreme heat, which means it stops doing its job properly,” Greensmith warned. If the oil appears dark, gritty, or low, it should be changed before driving. Serious oil-related engine damage can cost thousands to repair, with engine repairs on ClickMechanic’s platform ranging from £100 for minor work to well over £2,000, depending on the car and the severity of the damage.
5. Air Conditioning
“Your air con circulates a refrigerant gas around the system to cool the air before it reaches you – and if that refrigerant leaks, which often happens unnoticed over winter, you'll get nothing but warm air when you need it most,” Greensmith said. If left unchecked, the compressor can seize from running dry, leading to heating and air conditioning repairs that average anywhere from £300 to over £800, depending on the make of car.
Preventive Advice
Greensmith urges drivers to perform these checks before setting off in hot weather to avoid being stranded or facing costly repairs. A simple five-minute inspection can prevent many of these issues, ensuring safer and more reliable driving during the summer months.
