Assuming you are asking how long a car can run with an overheating engine before sustaining damage: the answer is not long. An overheating engine can cause severe damage to the cylinder head pistons and bearings among other things. If you allow an engine to overheat long enough it will seizure and cause irreparable damage.
How long does it take for an engine to overheat? That depends on many factors such as the temperature of the coolant the condition of the cooling system the outside temperature and the speed at which the car is driven.
A car’s cooling system is designed to keep the engine at a constant temperature usually around 200 degrees Fahrenheit. The coolant does this by circulating through the engine and absorbing the heat. The cooled coolant is then circulated back through the engine to absorb more heat.
If the cooling system is not functioning properly the coolant will not be able to absorb the heat and the engine will overheat. The engine will continue to get hotter until it seizes at which point the damage will be done.
So how long can a car overheat before damage? It depends but not long. If you think your car’s engine is overheating pull over and call a tow truck. It’s not worth the risk of damaging your engine.
How long can a car idle without damage?
You can idle your car for as long as you want without damaging it.
However if you do it for too long you will eventually run out of gas.