How Does My Cooling System Work?

Your cooling system is what keeps your car from having a meltdown. Whether you're cruising down the highway at 75 miles per hour or stuck in a 10-block traffic jam at rush hour, your cooling system is working hard to keep your engine operating at the right temperature. If you didn't have some way to cool things off, your engine would turn into a solid block of useless metal in no time flat. These days your cooling system has a bigger job than just keeping the radiator from belching steam all over the place. Your engine is designed to run at an optimum temperature. This is not just the best temperature for performance, it's more about maintaining the right conditions for all of your emission control systems to function at their peak. That's why your engine has so many ways to heat up quickly on a cold morning!

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What's In My Cooling System?

Nick Ares/Flickr

All of the parts that make up the cooling system have one goal of moving coolant around the engine so it can absorb and dissipate heat. The basic system is made up of the following components:

Basic Components of an Automotive Cooling System

  1. radiator
  2. radiator top hose
  3. radiator bottom hose
  4. water pump
  5. thermostat
  6. thermostat housing
  7. electric cooling fan
  8. thermo-time switch
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The radiator is the most prominent part of the system. Coolant that has traveled through the engine is pumped through the tubes of the radiator and is cooled off for another round. The radiator has many channels on the inside so that the coolant travels all over the place, dissipating heat at every turn. It also has lots of cooling fins on the outside. These fins increase the surface area so that even more heat can escape into the air flowing around the radiator. 

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Radiator Hose

Your cooling system has a number of rubber hoses that move the fluid from one place to the other. These need to be replaced before they become brittle and cracked. Even the smallest hose can fail and leave you on the side of the road. 

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Water Pump

The water pump does what you think it does - pumps the coolant through the system. The pump is belt driven, except in the case of some race cars that use an electric water pump. If your water pump is leaking coolant under the car, this is a heads-up to replace the water pump when you can. 

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Your engine isn't always the same temperature. When you start it on a cold morning, you want it to get warm quickly to get the emission controls working fully. If you stop in traffic, you want it to cool itself off. The thermostat controls the flow of coolant so that it cools down more or less depending on the temperature of the coolant. It rests in a housing just after the radiator bottom hose.

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Electric Fan

Many cars these days have an electric fan for either primary or added cooling. The fan draws air through the radiator when you aren't moving fast enough to get things cooled down. There is often also an electric fan on the air conditioning system.

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Thermo Time Switch

Also known as the fan switch, this is the temperature sensor that tells the electric fan when to blow. When the coolant reaches a given temperature, the electric cooling fan switches on to draw more air through the radiator.