Because they have an engine and if the engine cant have a break it will explode.
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There can be several reasons, depending on the car/truck and the overheating problem. Check the basics after it has cooled awhile i.e. Check hoses, fan belt, oil level, coolant level and look for obvious coolant leaks. If those things are OK, give it another try and I bet it will start. NOTE: This should be a reminder to have the vehicle serviced ASAP.
Overheating an engine can seriously damage the heads. Check for water in the oil. It may look milky.
The Dodge intrepid will not start after overheating because it blocks the radiator cap.
Check the cars ignition coil and crank sensor. Either of these could be overheating and causing the car to not start until it sits for a while.
overheated and wont start
How do you know that it is your car?
After it cools if there was no damage sustained during overheating
if the engine does not turn over it may be seized Most modern fuel injected engines have a cutout for overheating , preventing you from cooking the engine. When carburetered engines overheat , the carby may stop working because of fuel vaporization, sometimes called vaporlock.
It wont start
Your car wont start. lol
that's probably a sensor that shuts the engine off to protect from damages of overheating. it happens in some newer type cars.
What have you welded ?
use jumpers