What to Do When Your Car Overheats in Antelope Valley Heat

How hot does it get in the Antelope Valley?

Hot enough to push any cooling system. At Lancaster’s William J. Fox Field, NOAA’s 1991–2020 normals put the average high at 97.6°F in July and 97.8°F in August. The station averages about 36 days a year at 100°F or hotter, and about 109 days at 90°F or more.

The highest reading in the station’s digital record, which starts in 1974, is 115°F. It was reached on June 30, 2013, and again on July 7, 2024.

The National Weather Service office in Los Angeles/Oxnard issues heat warnings for its Antelope Valley forecast zone, which includes Lancaster and Palmdale. Since 2025 they have been called Extreme Heat Warnings, and the NWS archive shows four for the zone in 2026 through mid-October. Rosamond, across the Kern County line, is forecast by the NWS office in Hanford. Check weather.gov/lox before a long summer drive.

What should you do the moment the gauge climbs?

These steps are where AAA and carmakers’ manuals agree:

1. Turn off the A/C. AAA, Kia and Nissan all say to. It takes load off the engine.
2. Get safely off the road. Signal, turn on your hazards and pull as far from traffic as you can: an exit, a parking lot or a wide shoulder. Shift to Park and set the parking brake.
3. Decide about the engine using your owner’s manual. The sources differ here; see the next section. If coolant is leaking or the cooling fan isn’t spinning, turn the engine off.
4. Leave the hood shut while it is steaming. AAA’s Mountain West Group says to wait at least 20 minutes before opening the hood, because pressurized coolant can cause severe burns.
5. Never open the radiator or coolant reservoir cap while the engine is hot. Kia’s and Nissan’s manuals both say so.
6. Call for help. AAA advises against adding coolant and driving on. Its advice is to call for a tow.

Should you turn the engine off or leave it running?

It depends on your car, and the sources disagree. AAA says to turn the engine off right away. Kia’s and Nissan’s owner’s manuals say that if no coolant is leaking and the cooling fan is running, you can leave the engine idling to help it cool, and to shut it off if either check fails. Kia also says to shut it off if steam is coming out.

The section of your manual called “if the engine overheats” is the one to follow. If you can’t check it, or you’re not sure what you’re seeing, AAA’s advice to turn the engine off is the cautious default.

Can you add coolant?

Only after everything has cooled, and only the way your manual describes. Nissan’s manual says to add coolant only when the engine is cool, through the reservoir. AAA warns that adding coolant and continuing to drive risks burns and major engine damage.

Topping up also doesn’t fix the cause. A leak, a broken belt or a fan that won’t run will overheat the engine again.

How do you wait safely in the heat?

• On a freeway shoulder, California’s Driver Handbook says to stay inside with your seat belt on unless there is no shoulder or safe area. Dial 511 for motorist aid; call 911 for an emergency.
• Watch the cabin temperature. A parked car heats up fast. The National Weather Service notes that the inside of a parked car can go from safe to dangerous in a few minutes, and that heat illness can strike even when it is only in the 70s outside. If the engine is off and the cabin is getting dangerously hot, get everyone out on the side away from traffic and wait well clear of the lanes. AAA’s overheating advice is also to get everyone out and away from traffic.
• Never leave a child or a pet alone in the car, even with the windows down.
• Keep water in the car all summer, enough for everyone, including pets.
• Tell the dispatcher if you have children, pets or anyone vulnerable to heat with you.

The Highway 14 breakdown guide covers shoulder safety in more detail.

Where do engines work hardest around here?

• CA-14 over Soledad Pass. Between Palmdale and Santa Clarita, the 14 crosses Soledad Pass near Acton, at about 3,200 feet according to Wikipedia’s figure from the federal place-names database (other sources differ slightly). Fox Field in Lancaster sits at about 2,338 feet. A pass means a climb from either side, and northbound drivers coming home from Santa Clarita climb up through the canyon to reach it.
• Long climbs with a load. A full car, a trailer or a camper on any grade, with the A/C running in afternoon heat.
• Slow traffic on hot days, when the engine gets little cooling air.

On any climb, keep an eye on the temperature gauge. If it starts rising, turn off the A/C first.

When should you get a tow instead of driving on?

Get a tow if:

• the temperature gauge is in the red, or an engine temperature warning stays on,
• coolant is leaking, or there is a puddle under the engine,
• the cooling fan isn’t running, or a belt is broken,
• steam keeps coming from under the hood,
• the engine overheats again after it has cooled down.

AAA’s general advice is to call for a tow rather than add coolant and keep driving, because driving on risks major engine damage.

When you call, say the car overheated, whether you can see a leak, and whether anyone with you needs to get out of the heat. Your request goes to a towing provider serving the Antelope Valley. For a car stopped on a shoulder, see emergency towing. If the car turns out to have a dead battery rather than an overheated engine, see why desert heat kills car batteries, and for a jump-start or other on-the-spot help, roadside assistance.