There are warm, even hot days ahead. Is the coolant in your cooling system up to the task?

Warm summer days are coming to Richmond, some of them even hot; while that’s a pleasant thing to think about, one question you should ask yourself is whether the coolant protecting your car’s engine is up to the task.

In 2024, there were 24 days through the summer in Richmond where the temperature topped 90 degrees, and 63 days in the 80s.* That’s 87 days where the coolant in your car’s engine better be up to the task. Keep in mind that, with operating temperatures, a car can actually overheat on a bitterly cold day in winter, if the coolant isn’t able to keep the engine cool.

And it’s not just the coolant; your vehicle depends on an entire cooling system to keep the engine from overheating.

Your car’s cooling system starts with hoses and passageways to move the coolant through the engine and a radiator, as well as a heater core in the dashboard. You have an upper radiator hose where the coolant is returned to the radiator and a lower radiator hose where the coolant moves into the engine.

The passageways within the engine allow the coolant to flow through the engine collecting heat along the way. When it has moved through the engine, it passes through a thermostat and back to the radiator. A water pump is responsible for keeping the coolant flowing, though the thermostat may close and stop the process until the coolant has reached operating temperature. 

The radiator has coils of tubes built inside thin metal fins. Behind the radiator is a fan that pulls air through the radiator so that the heat in the coolant is transferred away from the coolant. By this process, we could also refer to the upper radiator hose as the hot hose and the lower radiator hose as the cool hose.

Another part of the cooling system is the heater coil in the dashboard. This comes in handy mostly in the winter where a fan blows air over the heater coil so the heated coolant shares the heat with the passengers in the car.

Another important part of the cooling system is the pressure cap, otherwise known as the radiator cap. It is designed so that, if the vehicle is overheating, where overheated coolant will expand and create pressure, the cap will release that pressure before another part of the cooling system fails.

If all these parts are in good repair and operating as they should be, the only question is whether the coolant is up to the job.

Coolant is not just coolant. Over time, it will lose its capacity to do its job. When that happens, a hot Richmond day could find you on the side of the road with an overheated engine.

* From June 1 through September.