Summer heat is especially hard on batteries (heat speeds up internal wear, so many fail in summer), cooling systems (hoses, radiators and water pumps work hardest), air conditioning, and tires (pressure rises and worn tires are more likely to fail). A quick summer check of the battery, coolant, AC and tires prevents most heat-related breakdowns.
The most common hot-weather problems
Dead batteries
Heat speeds up the chemical wear inside a battery. The damage often shows up as a no-start, sometimes in summer and sometimes on the first cold morning in fall. Test batteries older than three years before summer. See mobile battery replacement.
Overheating
Traffic, towing, steep grades and a hot day stack up against a cooling system with a weak fan, old coolant or a leaking hose. Know what to do if the gauge climbs: car overheating.
AC failures
Low refrigerant from slow leaks, failing compressors and dead condenser fans show up in the first heat wave. See car AC not blowing cold.
Tire blowouts
Underinflated tires flex more and build heat, especially at highway speeds with a full load. Check pressure in the morning when tires are cool.
Fluid problems
Low or old oil, coolant and transmission fluid all lose protection in extreme heat.
Belts and hoses
Heat and age crack rubber. A failing hose can burst under pressure.
Summer checklist
Battery load test
Coolant level and condition; check hoses and the radiator for leaks
Radiator fan operation (it should run with the AC on)
AC performance
Tire pressure (including the spare) and tread
Oil level and change interval
Wipers. Summer storms need good blades
Emergency kit: water, phone charger, sunshade
Protect your car on hot days
- Park in shade or use a windshield sunshade
- Don't leave people or pets in a parked car, ever
- Watch the temperature gauge in traffic and on long climbs
- Keep a little extra coolant and water in the trunk
Frequently asked questions
Does heat really kill car batteries?
Yes. Heat accelerates the wear inside the battery, which is why batteries in hot climates often have shorter lives.
Should I lower my tire pressure in summer?
No. Set pressure to the number on the driver's door sticker, measured cold.
Is it bad to run the AC all the time?
No. It's designed for it. If the engine starts running hot in traffic with the AC on, have the cooling system checked.
Book a summer check
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