How the Engine Cooling System Works

How the Engine Cooling System Works

In order to diagnose your engine properly, everyone needs a few pointers. That’s why City Garage DFW continues to offer free information about your vehicle health. With the constant changes in the manufacturing of cars, there will always be new subjects to speak about. We try to keep you abreast of the inner-workings of your car, so you can know how to diagnose your vehicle troubles and find a professional automotive solution when you need it.


Today, we’re going to be discussing how the engine cooling system works to regulate your engine’s temperature. This part of your vehicle is pivotal to getting anywhere, so we thought it bears some mentioning. Here’s how the whole system works:


Pressure and Liquid Coolant

Your car engine must be cooled continuously to avoid overheating. There are several methods of doing this. The first and most common of them is the liquid coolant system. This works by circulating coolant, which is usually a mixture of water and anti-freeze, through special cooling passages. Whatever coolant is used, liquid cooling systems have the engine block and cylinder head connected by cooling channels. At the top of the cylinder head, all of the cooling channels end up at a single outlet, which then seeps into the engine. As the used up, hot coolant is pumped out of the engine and into the radiator, where it is taken and cooled again. Thus the cycle repeats.


The pressure in the engine is regulated by the radiator cap, which features a built-in pressure valve. Once that mechanism is tripped, the added coolant creating the pressure is pumped through an overflow pipe. In newer cars, that coolant is sent to a reservoir expansion tank where it cools, and is sucked back into the engine to be re-used in the cycle.


The Fan

A constant flow of air is needed to regulate the temperature of the radiator. When the car moves, the fan spins naturally. However, when the car is sitting, a fan is used to provide that air flow. Some cars have an electric fan that is switched on and off depending on the temperature of radiator. Because water expands when it freezes, the engine coolant could freeze and expand to such a point to where it cracks the radiator or engine block. Anti-freeze is added to the engine coolant to lower its freezing point. Many people believe that anti-freeze should be drained each summer. In reality, the anti-freeze in your engine should be able to last you about 2 or sometimes 3 years.


Air Cooled Engines

In air cooled engines, the engine block and the cylinder head are made up of deep fins on the outside of them. A duct usually runs through the fins and an engine-driven fan blows air through the duct to take away heat from the fins. With a temperature controlled valve that controls the amount of air being passed around by the fan, the engine remains at a steady temperature at all times.