Car Overheating? What to Do Right Now and What It Costs

What to do right now

1. 1Watch for the warning signs. A temperature gauge well above its normal position, steam from under the hood, a sweet smell, a warning light, or the car feeling sluggish.
2. 2If you can't pull over right away, turn the A/C off and turn the heater up to full. That moves some engine heat into the cabin. It's a short-term stopgap only.
3. 3Pull over as soon as it's safe, switch on your hazard lights, and shut the engine off.
4. 4Wait at least 20 to 30 minutes, until the hood and hoses are cool to the touch. Stay away from the front of the car while it cools.
5. 5Don't open the radiator or coolant reservoir cap while it's hot, and don't pour cold water onto a hot engine.
6. 6Once it's cool, look at the coolant reservoir. If it's empty, you probably have a leak. If it's full and the car still overheated, adding more coolant won't fix it.

A note on topping up coolant

If you add coolant once the engine is completely cool, use the type listed in your owner's manual. Different coolant types shouldn't be mixed, and a premixed 50/50 product can go straight in. Plain water can get you to a shop in an emergency, but the system will need to be properly drained and refilled afterward. Avoid "stop-leak" additives, which can clog the radiator and other parts of the system.

Why cars overheat

The cooling system moves heat out of the engine with coolant, a pump, a thermostat, a radiator, hoses, and a fan. When any one of those fails, the engine can overheat. The clues below can help narrow it down, but only a proper inspection will tell you for sure.

What a cooling-system inspection covers

A good inspection goes beyond a glance at the reservoir. It typically includes checking coolant level and condition, looking over the hoses, belts, radiator, and cap, pressure testing the system to find leaks, and making sure the fan comes on when it should. We cover all of this in our radiator and cooling system service, including coolant flushes with the correct coolant for your vehicle. If your car has already overheated, it's also worth checking for internal engine damage before replacing parts.

What does it cost?

These are general ranges gathered from published repair-cost guides, and they disagree with each other quite a bit. Bay Area labor rates often run above national averages, and exact prices depend on your make and model and on the nature of the problem. Notice the gap between the first rows and the last one: catching a leak or a weak thermostat early is far cheaper than repairing an engine that has been run hot.

Before a holiday road trip

Thanksgiving week puts a lot of cars on long drives, and heavy loads, mountain grades, and stop-and-go traffic all work the cooling system hard. A few minutes of checking beforehand is worth it:

• With the engine cold, check that the coolant reservoir is between the minimum and maximum marks.
• Look under the car where you park for sweet-smelling, colored puddles.
• Look at the hoses and belts for cracks, bulges, or fraying.
• Check the date of your last coolant service against the interval in your owner's manual.
• Keep an eye on the temperature gauge as you drive, and bring a charged phone and some water.
• If anything looks off, have the system inspected before you leave, not on the shoulder of the freeway.

Overheating in San Francisco

Idling in traffic around SoMa and climbing steep hills put extra demand on the cooling system, and a marginal fan or a slow leak can show up here first. If your gauge is running high, you see a puddle, or you smell something sweet, don't wait for it to boil over. If you can safely drive it, bring it in. We're open Monday to Friday starting at 8 a.m., walk-ins are welcome, and you can also book online.