 I'm Emmy here again and welcome to another episode of Cobb U. Now on the first half of our series, we talked about all the systems that work together to create the power that turns your wheels. Now with that power comes heat. So today's topic is an often overlooked one, your engine's cooling system. We learned that the combustion process is actually a controlled burn. Naturally with burning, there's gonna be heat. And with the engine spinning at thousands of revolutions per minute, there's gonna be friction, which is gonna make more heat. Now some heat is good for the engine, but an excess is not. We need to control the amount of heat that the engine produces via the tune and use oil and coolant to transfer heat away from critical engine components. The number one job of oil in the engine is lubrication. However, just like in the turbo, oil flowing through the engine helps dissipate heat. And exhaust gases also carry some heat with them as they exit through the tailpipe. Now while oil and exhaust carry lots of heat away from the engine internals, when most people think of the cooling system, they think of the radiator. The cooling system is not just the radiator though. So let's take a look at what makes up the cooling system and how the components work hand in hand to keep the temperature of your engine in check. For today's demonstration, we're gonna be looking at a radiator and associated parts. For more information on how engine oil cools, pistons, bearings, and other components, you can take a look at the extra credit. Also, the components we're looking at might differ from your setup, but the concept's the same. The components we're gonna discuss further are the radiator, fan, water pump, coolant overflow tank, thermostat, heater core, coolant temperature sensor, and all the necessary plumbing and clamps. The radiator core is made up of layered internal and external water and air passages that lay perpendicular to each other. The internal ones where our coolant will travel run from top to bottom. The external ones which have outside air passing through them run front to back. It has an inlet and outlet port and radiator pressure cap. The coolant overflow tank is used to allow heated coolant to escape because of the built-up pressure. The fan has blades to move the air, a motor, mounting tabs, and an electrical connector for power. Now the water pump is the heart of the cooling system and as the name suggests, pumps coolant through the system and is generally driven by the engine drive belt. The thermostat is a valve that regulates the flow of coolant and helps maintain the proper operating temperature of the engine. It will either keep the coolant in the engine or it will route it to the radiator. Now the main valve has wax inside that melts as hotter coolant hits it, making it open and route coolant to the radiator. It will harden when cooler coolant hits it, which will make it close and keep the coolant in the engine. Thermostats can be found in different places depending on your car. On some models the thermostat is installed with the water pump. On others it may be located before the coolant re-inters the radiator. The coolant temperature sensor is used to monitor the coolant temperature which the ECU then uses to manage fuel injection and ignition timing. It's also used to control when the fan turns on and off as well as displaying temperature on your gauge. The heater core is where we get our heat from. It's comprised of the core itself and in-light and outlet ports. And last, all the necessary plumbing and clamps to put it all together. Now that we've covered our primary components, let's take a look at how they all work together. Now keep in mind that in some vehicles the flow of the water may be reversed, but the functionality will be the same. Throughout the engine block and head are coolant passages, also known as water jackets. Inside these passages is where the coolant will flow or remain still in an effort to absorb the heat from the engine and carry it away. All these passages are designed to help keep the temperatures all over the engine even and keep the engine at proper operating temperature. When your car is running, the coolant is going to do one of two things. If the thermostat is closed because the coolant is cold, then it will remain inside the passages absorbing heat. As the coolant gets hot, usually between 160 to 190 degrees Fahrenheit, the thermostat reacts to that heat and opens its valve and the coolant is free to float into the radiator to cool down. Just like an intercooler, as the coolant moves through the internal passages of the radiator core, its temperature decreases because the heat transfers from the coolant to the metal core. Cooler air from outside passes through the external fins on the core in an effort to reduce the temperature of the core itself. That air will come from either the car being in motion and air passing naturally or in like stop and go traffic, the fans turning on. The fans are controlled by the ECU after it gets its reading from the coolant temperature sensor. Based on that reading and other factors such as vehicle speed, the ECU will turn the fan on and off as needed. Once the coolant makes its way through the radiator, it then flows back to the water pump where it will either go back into the engine if the thermostat is open or just wait patiently for it to open again. One cool bit of info is that some modern cars don't use a thermostat. Instead, they have an electric pump that can be turned on and off having the same effect as a thermostat. And just like fans, the pump is controlled by the ECU based on input it gets from various sensors. Going back to the radiator, the coolant inside is very hot and under high pressure. So that pressure needs to be regulated to allow venting in the event of the pressure inside increasing too high. If increasing pressure is left unchecked, it can cause damage to the system. The radiator cap on top not only covers the radiator but helps to regulate that pressure by diverting coolant to an overflow tank, which has more space for the pressure to dissipate in and lower. It does this with a rated spring inside. Once the pressure in the radiator exceeds the spring max PSI rating, it pushes up and opens the valve where the coolant can flow. Once the coolant has cooled, the pressure drops. And with a drop in pressure, we get vacuum. This vacuum then sucks up the coolant and it flows back into the radiator and continues on. This doesn't happen all the time. The overflow tank is designed as a safety net for the engine to avoid damage under higher pressures. Now that we've talked about the coolant and the engine and the radiator, there's two more places that coolant will flow, the turbo and the heater core. We'll start with the turbo and talk about a major misconception, turbo timers. Turbo timers were used back in the day when turbos were typically not water-cooled and needed a minute to cool down before you shut off your engine. So they would keep the engine running for a few minutes even after you took the key out. Nowadays, most turbos are water-cooled so by the time you let off the throttle and find a place to park, your turbo's cool enough to shut off your engine so turbo timers aren't really needed anymore. Moving on from the turbo, it's on to the heater core to get the heat for the cabin. The heater core doesn't affect the engine temperature but uses the hot coolant to get you your heat. When you switch your heat on, the coolant takes a detour through the heater core. A fan then blows air through the heater core to move heat into the cabin. Then the coolant returns back to the main system. And that's the long and short of it. As long as your engine's running, this just cycles over and over again until you shut it off. You can modify and upgrade just about any component in the cooling system that we outlined earlier from a thermostat that operates at a cooler heat range or a radiator that's made of all aluminum construction. There's a part to accommodate just about any one or need. But before getting that race car-inspired component that may reduce the efficiency of the part you're replacing, consider if the upgrade's beneficial to your setup or how you use your car. Instead, time and time again, do what's best for your car and your setup because what's right for me might not be what's right for you. Lastly, when doing this type of part install, you will generally use these kinds of tools, ratchets, sockets, and extensions, screwdrivers, picks, and pliers. And now it's time for the pro tip of the day. Today, let's talk maintenance. We just learned that the thermostat is the one component that directly controls the flow of the cooling system. Yet this little guy is often forgotten. Over time and use, thermostats can go bad. They can get stuck losing control over the coolant. Now if they get stuck open, then the engine will never reach its optimal operating temperature because the coolant is constantly going to the radiator to get cooled. And if they get stuck closed, well then you're running into overheating issues because the coolant never makes its way to the radiator to get cooled. And that just isn't cool. A thermostat is pretty straightforward to replace, so we'd recommend you swap it out if it's had a long, happy life or if you push your car all the time. Don't forget about this little guy. It can save you a ton of money in the long run. That's gonna do it for this episode. So now that we've learned how to make power, manage tunes and parts, and keep that power as heat in check, we now need to transfer that power to the wheels. So in the next couple episodes, we'll learn about transfer of power, how to keep it on the ground, and how to stop it when needed. Thanks for joining us. Be sure to subscribe to our YouTube channel so you can check out future episodes. I'm Emmy, your host for CobbU. Remember, check out cobbtuning.com for all your parts and tuning needs. Do you like the storage solutions featured in our studio? Then visit sonictoolsusa.com to get more detailed product information.