Heatwave Driving: Keeping Your Car (and You) Cool
To keep your car cool in a heatwave, make sure the coolant is at the right level, the tyres are in good condition and correctly inflated, and the air con works. Heat increases the strain on the cooling system, battery and tyres, so a few checks before a hot-weather journey prevent most summer breakdowns.
Cooling system and overheating
Hot weather puts the engine's cooling system under the most strain, especially in slow traffic when there is little airflow. Low coolant, a weak thermostat or a tired water pump can tip a car into overheating on a hot day.
Check the coolant level when the engine is cold, between the marks on the expansion tank, and top up if needed. If the temperature gauge climbs towards the red in traffic, that is a warning the system is struggling and worth getting checked before it boils over.
Tyres in the heat
Warm roads and motorway speeds raise tyre temperatures, and heat finds any weakness in a worn, damaged or under-inflated tyre. Most summer blowouts trace back to a problem that was already there.
Check tread and condition, and set pressures to the correct cold figure (do not let air out for the heat, as the recommended pressure already allows for it). Our summer tyre care guide covers this in more detail.
Heat is hard on batteries too
It is a myth that only cold kills batteries. High temperatures accelerate the chemical wear inside a battery and can evaporate its fluid, which is why many batteries actually fail in summer or shortly after a heatwave.
If your battery is a few years old and starting feels slow, a hot spell can be the final straw. A quick battery test before a heatwave trip avoids being stranded in the heat.
Air conditioning and staying alert
Working air con is a safety feature in a heatwave, not just a comfort. A hot, stuffy cabin makes drivers drowsy and less alert, which is dangerous on a long, warm drive.
If the air is no longer cold, the system likely needs a re-gas. Spring and early summer are the busiest times for this, so book ahead. We offer an air con re-gas with a leak check so you stay cool and focused.
Protecting yourself and passengers
Carry water on hot journeys for yourself and passengers, and never leave children or pets in a parked car in warm weather, even for a few minutes, as cabin temperatures climb dangerously fast.
A sunshade keeps the interior bearable when parked, and parking in shade where you can helps. Plan longer journeys for cooler parts of the day, and take regular breaks, as heat adds to driver fatigue on top of the usual tiredness of a long drive.
A quick pre-heatwave check
Pulling it together, before a spell of hot weather or a long summer drive, check the coolant, tyres, battery and air con, and top up screenwash for dusty, bug-spattered screens.
If anything is borderline, sort it before you travel rather than risking a roadside breakdown in the heat. We are happy to give the car a quick summer once-over and put right anything we find, so you can enjoy the sunshine without worrying about the car.
Frequently Asked Questions
Why do cars overheat in hot weather?
Hot weather strains the cooling system, especially in slow traffic with little airflow. Low coolant, a weak thermostat or a failing water pump can then tip the engine into overheating. Check the coolant level cold and watch the temperature gauge; if it climbs towards red, get it checked.
Does hot weather damage car batteries?
Yes. High temperatures accelerate the chemical wear inside a battery and can evaporate its fluid, which is why many batteries fail in summer or after a heatwave, not just in winter. If yours is a few years old and starting feels slow, have it tested before a hot-weather trip.
Should I lower my tyre pressure in a heatwave?
No. Your car maker's recommended pressures already allow for normal heat build-up while driving. Lowering pressure causes under-inflation, which generates more heat and raises the blowout risk. Always set tyres to the correct cold figure, even in hot weather.
Why is my air con important in a heatwave?
Beyond comfort, a hot, stuffy cabin makes drivers drowsy and less alert, which is dangerous on a long drive. Working air con keeps you focused as well as cool. If it is no longer cold, the system likely needs a re-gas, ideally booked before the hot weather arrives.
What should I carry in the car during a heatwave?
Carry water for yourself and passengers, keep screenwash topped up, and a sunshade helps keep the parked interior bearable. Never leave children or pets in a parked car in warm weather, even briefly, as cabin temperatures rise dangerously fast.
Book With Norwich Tyres & Auto Service
Need a hand from a real, independent Norwich garage? Call 07933 900901 or pop into Ber Street, NR1 3ES. Same-day tyre fitting is available on most common sizes, with free parking on site.
Hero image: “Sun setting at Birger Jarlsgatan, Östermalm (Stockholm)” by Tommie Hansen (source), licensed under CC BY.