How California heat can break your car — and what to do about it
Summer in California doesn’t just strain your air conditioning. It quietly wears down your car too.
High temperatures can drain your battery, overheat your engine and send your tires to the brink. And with wildfire season layered on top, your vehicle could be taking on more damage than you realize.
But the good news is that most heat-related car trouble is preventable.
Here’s what California drivers should know to stay safe, save money and avoid a breakdown this summer.
Do batteries fail faster in heat?
Yes. It’s not just the cold that’s tough on car batteries.
Hot weather speeds up chemical reactions inside your battery, which shortens its lifespan. Even a healthy-looking battery can suddenly die during a stretch of extreme heat.
If your battery is more than three years old, it’s at higher risk of failing. The Car Care Council says high temperatures are actually tougher on batteries than cold.
“When most motorists think of dead batteries that cause starting failure, they think of severe winter weather, but summer heat is the real culprit,” said Nathan Perrine, executive director of the Car Care Council. “Many battery problems start long before the temperatures drop. Heat, more than cold, shortens battery life.”
What to do:
Test your battery before a road trip.
Clean corrosion from terminals.
Consider replacing the battery after three years.
Engines are more likely to overheat
High temperatures can strain your car’s cooling system, making it more susceptible to overheating. AAA’s Chase R. Nacol, director of car repair operations for AAA of Northern California, Nevada and Utah, explains on AAA.com:
“Each car has a cooling system that is designed to cool the engine,” Nacol said.
He added: All sorts of elements in the car — a water pump, cooling fans, belts, and hoses — help keep coolant and air flowing through the vehicle constantly.
What to Do:
Keep an eye on your dashboard’s temperature indicator. If it rises above the middle mark it’s a sign to take action.
Ensure your cooling system, including hoses and belts, is inspected and maintained regularly.
If your car begins to overheat, pull over safely, turn off the air conditioning, and let the engine cool before checking coolant levels.
Tire blowouts are more common
Hot pavement and underinflated tires make a dangerous combination. Heat increases pressure and worn tread can lead to blowouts on long drives.
Doug Shupe, spokesperson for AAA Texas, told The Sun newspaper: “Not only are we dealing with warm air temperatures, but the roads get very hot. So, if your tires are in bad shape, that could cause a blowout.”
What to do:
Check tire pressure monthly.
Look for cracks or bald spots.
Don’t forget to inspect the spare.
Can wildfire smoke damage my car?
Smoke and ash from California wildfires don’t just affect the air you breathe — they can also harm your car.
“Cabin air filters are the first line of defense against contaminants that reduce vehicle cabin air quality for vehicle owners and their passengers,” Perrine said in a news release.
“The Car Care Council recommends that motorists in areas impacted by wildfires and those in surrounding states have their cabin air filters replaced. This simple, yet important, service will help ensure vehicle longevity as well as clean air inside the car.”
These filters trap smoke particles and other pollutants, helping keep the air inside your car cleaner.
It’s also important not to overlook the engine air filter. According to the council, engine air filters trap dirt particles, including soot, which can cause costly engine damage. They play a critical role in protecting the airflow sensor on fuel-injected cars from smoke and debris.
As a rule of thumb air filters should be inspected at every oil change and replaced annually or sooner if they show signs of contamination.
What to do:
Replace your cabin air filter more frequently during fire season to maintain good air quality inside the vehicle.
Use your car’s recirculate setting on days when smoke levels are high to limit outside air intake.
After driving through heavy smoke, have your engine air filter inspected and replaced if needed.
Other heat-related car issues to watch for
The heat can take a toll on many vehicle systems. AAA advises checking these areas to avoid costly repairs.
- Transmission Problems: High heat can cause transmission fluid to break down faster, reducing its ability to lubricate and cool. This can lead to overheating and costly damage.
- Brake Wear: Hot weather can increase brake pad and rotor wear, especially if you’re driving in stop-and-go traffic or downhill areas.
- Electrical System Stress: Extreme heat can cause wiring insulation to deteriorate faster, leading to shorts or failures in electrical components.
- Air Conditioning System Strain: The AC system has to work overtime in hot weather, and if it’s low on refrigerant or needs servicing, it can lose effectiveness — making your drive uncomfortable and your engine work harder.
- Fuel System Issues: High temperatures can increase fuel evaporation and potentially cause vapor lock in older vehicles, which disrupts engine performance.
Essentials to carry for California summer drives
Experts including AAA, the Car Care Council and the California Bureau of Automotive Repair recommend keeping these items in your car to prepare for California’s hot weather and unexpected issues:
Water: Stay hydrated and have water available for emergency radiator top-offs.
Jumper cables: Heat can weaken batteries, so having jumper cables is essential.
Spare tire kit: Always carry a spare tire, jack, and tire iron to handle flats.
Phone charger and portable battery pack: Ensure your phone stays charged for navigation and emergencies.
Flashlight with fresh batteries: Essential for nighttime repairs or emergencies.
Basic tool kit: Screwdrivers, pliers, and other simple tools can help with minor fixes.
Emergency contact numbers: Keep numbers for roadside assistance and your mechanic handy.
What to do if your car breaks down in extreme heat
Car experts emphasize quick, safe actions if you experience a breakdown during California’s summer heat:
Move your vehicle off the road: Find a safe spot away from traffic to avoid hazards.
Turn off the engine: Prevent further overheating and damage.
Activate hazard lights: Alert other drivers to your stopped vehicle.
Stay inside the car if safe: Use air conditioning sparingly to conserve fuel while waiting for help.
Call roadside assistance or emergency services: Don’t hesitate to get professional help.
Avoid opening the radiator cap immediately: Wait until the engine cools to prevent burns.
Use water cautiously: Only top off the radiator with water in an emergency and if available.
This story was originally published June 30, 2025 at 5:00 AM with the headline "How California heat can break your car — and what to do about it."
CORRECTION: This story has been updated to remove or correct inaccurate quotes and to clarify attribution and titles. It also was updated to include additional information.
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