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Car Overheating or Running Hot

Stop Driving

Overheating means the engine is running above its safe temperature range. The cause may be low coolant, a leak, a stuck thermostat, fan failure, water pump failure, blocked radiator airflow, or internal engine problems. Driving hot can damage the head gasket, cylinder head, or entire engine.

Stop driving — this can cause serious damage or be unsafe.

Check These First

Before diving into diagnosis, quickly verify these:

  • 1Pull over safely if the gauge climbs
  • 2Turn off the A/C
  • 3Do not open the radiator cap while hot
  • 4After the engine cools, check coolant level in the reservoir
  • 5Look for coolant leaks or steam
  • 6Listen for radiator fans when hot
  • 7Note whether overheating happens at idle, highway speed, hills, or stop-and-go traffic.

Most Likely Causes

Ranked from most to least common — start at the top.

Related Symptoms in Cooling

Other problems to check if this isn't your issue.

Frequently Asked Questions

Is it safe to drive with an overheating engine?
No, it's not safe. Continuing to drive an overheating engine can cause severe damage like a blown head gasket or cracked cylinder head, which costs thousands to repair. Pull over immediately, turn off the engine, and let it cool before proceeding.
How much does it cost to fix an overheating car?
It depends on the cause. A simple coolant leak might cost $100-$300 to fix, while a failed thermostat ranges from $200-$500. A water pump replacement can cost $500-$1,500. If the engine is damaged from overheating, repairs can exceed $3,000.
What should I do if my car starts overheating while I'm driving?
Turn off the air conditioning (to reduce engine load), pull over in a safe location, and turn off the engine. Never open the radiator cap while hot—you can get severely burned. Once cooled, check your coolant level. If it's low or you see a leak, call for roadside assistance rather than risk further damage.