The potential causes of a car overheating at highway speeds are a stuck thermostat, a restricted radiator, or a kinked hose. Regardless of the problem, you'll likely need a mechanic's help in finding and fixing this issue.
Once it reaches maximum“Hot”, you've got around 30 to 60 seconds, no more, before you start to do serious damage, such as seized up valves or even pistons. Chances are 90–1 that you've got a major coolant leak somewhere.
If you find that you've got a car running hot but not overheating there might be a few reasons: Clogged or damaged radiator. Low coolant level. Damaged water pump or thermostat.
If you absolutely must drive with an overheating engine, keep your eye on the temperature gauge. Every time it gets hot, pull over, turn the car off, and wait for 10-20 minutes as it cools.
If you have to drive an overheated engine, only drive it after the engine cools down. If the overheating problem is not recurrent, the problem might have been caused by factors such as driving during a hot day, leaving the air-conditioning on, or being stuck in traffic congestion.