How engine cooling system works

coolant cap

Why engine cooling is necessary?

For a car to operate, we know it needs an engine and transmission, among a host of other components. The engine is a combustion engine that needs certain things to make it work, one of which is the engine cooling system. This works with a fluid referred to as engine coolant, which can be plain water, but usually has antifreeze mixed in with the water.

Internal combustion engines produce a sizeable amount of heat which causes the engine components to expand by a certain amount as determined by design and engineering. Having a process to cool the engine, the engine cooling system, keeps that expansion within that certain amount as they designed it, staying within the tolerance range set with the engineering of the design. There are two distinct ways a car engine is cooled. 

What are the two types of cooling systems?

The two types of engine cooling system of cars are: 

  • Liquid Cooling – this system circulates coolant and water through hoses and pipes inside the engine. The coolant and water pass through the hot engine, absorbing the heat generated and cools the engine. The coolant and water go from the engine and goes through the radiator. Then the heat from the coolant and water is transferred to the air that then blows through the exchanger. 
  • Air Cooling – they used this system on older model of cars, and today, there are a select few that use it today. These type of cars operate with an engine cooling without radiator instead of circulating coolant and water through the engine. There are aluminum fins covering the engine block that pull the heat away and a powerful fan forces the air over the fins, cooling the engine by moving the heat to the air. 

For this article, we will focus on engine cooling system that is liquid-cooled. 

Why do you need an engine cooling system?

The prime purpose of engine cooling system is to transfer heat to prevent damaging the engine from the coolant and water boiling and freezing.  If the coolant reaches a boiling point, vapors form, and the heat isn’t transferred properly, allowing the engine metal to heat up to appoint that it could melt. The liquid serves as engine cooling and lubrication for the metal and non-metallic components of the engine and the engine cooling system. 

How is an engine cooled?

There are three vital functions of a car’s cooling system within six key parts.  The three vital functions are: 

  • Removing excess heat from the engine
  • Get the engine at the ideal operating temperature
  • Maintain an efficient operating temperature 

Those vital functions are achieved by using these six key engine parts: 

  • The engine
  • The radiator
  • The water pump
  • The cooling fan
  • The hoses
  • The thermostat 

If you have ever been stuck in traffic on a scorching summer day and have your car overheat, you got a surprise lesson on the importance of an engine cooling system. The following process keeps the engine at the optimum temperature for expanding at that designed and engineered tolerance that we mentioned earlier. 

For the combustion process of an engine cooling system, part of the fuel energy is transformed into heat, which is transmitted to the coolant. The water pump then circulates that coolant through the engine, through hoses that transport the heated coolant to the radiator. There, the heat changes into air and cools it, then pulls that air past the engine. The coolant is returned back to the water pump, and it is recirculated. 

radiator close up

How do you diagnose a cooling system? 

Coolant is important to maintain an engine’s temperature. If the engine cooling system doesn’t have any coolant, what happens? The following is likely to happen:

  1. Temperature gauge rises, and warning lights go off.
  2. Engine will shut down on newer cars.
  3. Engine parts are damaged if the car doesn’t have the engine shut down feature. The parts that overheating can affect are cylinder head, piston timing, head gasket, water pump, and bent or warped rods.
  4. Other potential issues resulting from theengine cooling system not having any or enough coolant include steam coming from under the hood and/or out the tailpipe, the hood gets extremely hot, and the inside of the car heats. 

When a newer car runs out of coolant, it won’t cause damage instantly, but if you keep driving it after the gauge indicates the engine is hot, that will damage it. Many new cars today will go into ‘limp mode’ and you can get to a safe place, but it shouldn’t be driven on the roadways in that mode for a long distance. 

How Do You Know Your Car Needs Coolant?

The engine cooling system will give you warning signs before it gets damaged. It is up to the driver of the car to realize the warning signs and get the problem addressed. The common warning signs are: 

  • The temperature gauge creeps upward, or a heat light comes on
  • Car is blowing hot air even with the AC on 
  • Car is using an excessive amount of gas 
  • You notice a sweet odor coming from the car 

As you read this article, you may be asking “How can I cool my car engine?” and for the non-mechanic person, we suggest the following:

  1. Turn the air conditioner off.
  2. Turn the heater on.
  3. Put the car in neutral or park and rev the engine.
  4. Park the car if you’re driving and open the hood.

It takes a car at least thirty minutes for the engine to cool down. After that, you can open the radiator with caution, and add coolant if needed. The best thing you can do is call a professional towing service to get the car and take it to your mechanic to check your car’s engine cooling system and advise you from there the next step. Need service for your engine cooling system? Call Express Auto Repair & Emissions at 847-895-9131 today.