What happens to a liquid when it gets hot? It expands. Just like a person whose temper gets the better of him, as the coolant expands in the radiator, it may seek a way to relieve that pressure. You probably won’t like what happens when it finds that place.

The place where the pressure is relieved is the place where steamed coolant will erupt from under your car’s hood.

By the time this happens, your vehicle is overheating. Keep driving with an overheating car and you could ruin the engine or cause other problems. This is a stuck-on-the-side-of-the-road type of emergency. 

The way to avoid finding yourself stuck somewhere as your radiator blows steam under your hood is to have your cooling system checked now.

Checking your cooling system will include checking for leaks. The following are places coolant may ‘let off steam’ in the form of a high-pressured leak:

• The radiator
• The radiator cap
• Radiator and heater hoses
• Gaskets, such as under by the thermostat
• Through a crack in the engine block (this is the one where you have to replace the engine)
• The heater core

Clearly, the coolant has numerous places where it can ‘choose’ to let off steam. But one of the critical ways to avoid that problem, as part of the cooling system check, is to ensure that the coolant itself is up to snuff. Overtime, coolant loses its mojo. It can no longer take the high temperatures and keep its cool.

Another critical component in the cooling system is the aforementioned thermostat. The way a thermostat works in a car is that it opens and closes at pre-determined temperatures. When the engine is cold, the thermostat will remain closed until the coolant reaches that temperature. Then it will open to allow the coolant to flow through the radiator so that the fan can pull air through and carry much of the heat away.

That brings up another critical part of the cooling system – the fan. As mentioned above, the fan pulls air through the radiator to cool the coolant within. In older cars, the radiator was fixed to the engine. When the engine turned, the fan also turned. 

These days, the fans are generally electric and, like the thermostat, operate when specific temperatures are reached.

Think about it this way, if you have your cooling system checked, you’ll avoid having your car blow its top and you won’t blow your top because you’re stuck on the side of the road.