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Keeping Cool: What Consumers Should Know About Their Vehicle's Cooling System

American Government Special Collections Reference Desk

Keeping Cool: What Consumers Should Know About Their Vehicle's Cooling System

Ali Bell
March 17, 2013


Is your car running hot? Is your vehicle's air conditioning not blowing cold? After reading this article, you will have a basic understanding of your car's cooling system, the problems associated with it, and the services needed to properly maintain the vehicle and avoid further costly repairs.

Antifreeze and the Cooling System As most consumers are aware, the cooling system has antifreeze; the most common antifreeze is ethanol glycol. Basically the ethanol glycol is mixed with water and it raises the boiling point of water. Water has a boiling point of 212 degrees at sea level. When you add antifreeze to it, the boiling point is increased to about 240-250 degrees.

The other important thing that antifreeze does is lower the freezing point. You do not want cars in cold climates to have the coolant freeze because that can cause cracking of blocks, cylinder heads and water pumps when the water freezes inside of a motor. So it is very important that there is a proper amount and mixture of coolant. The antifreeze has the added component of rust protectors, the importance of which will be discussed below.

The importance of a Cooling System Flush Coolant is so important, that the take home message today is: Don't be guilty of reducing the life of your vehicle by failing to get the cooling system flushed regularly! It should be done every 30-50,000 miles. Normally in an average car or light truck the price is less than $100 for the service. The benefit to regular cooling system flushes is that it prolongs the life of the radiator, water pumps, thermostats, hoses, head gaskets, and everything that is exposed from the inside out to that coolant. The coolant also has rust inhibitors in it. If you neglect this service, coolant becomes corrosive over time and it tears up the seals in the water pump, corrodes the head gaskets, and eats holes in the radiator and heater core. So that $100 service is a tenth of the cost of some of those things to repair. Like any other service, it costs money, but it is a lot cheaper than the repair of those components.

What is involved in a cooling system service If you take your car in to us for a cooling system flush and service, we will first of all visually inspect for external leaks. We will also inspect the drive belts, hoses, the fan clutch or your electric fan operation. We will check the front of the radiator for debris. What we find here, especially in Utah, is a problem stemming from our roads having a lot of dirt and other matter on them. Over time, some of that debris can go through the front of the condenser. The condenser sits in front of the radiator and is what cools off the air conditioning gases. The radiator is right behind the condenser. The debris will go through to the front of the radiator and impact into the radiator. You get what looks like a birds nest, and is made up of a bunch of material similar to what a bird uses to build its nest. It can get so impacted that you have no air flow through the radiator. What we have noticed is that people do not recognize that their car has been running warm; but they will bring it to us in the summer and say that their air conditioner has stopped blowing cold. They often think that they need a recharge for the air conditioner. But what we find more commonly is this blockage problem from debris. The cooling fan, which is behind the radiator, draws air through the radiator. It also has to draw air through the condenser to cool off the gases. When that debris is blocking air flow, there is no air flow through the condenser and it

becomes a problem. With those high pressures in an air conditioning system from the gases that are being compressed to make the air conditioner work, without cooling that condenser off, it ruins air conditioning compressors and other parts. The cooling system service is very important because we also look at other items that may be affected from lack of maintenance.

After looking at all those components, and making an assessment, we will then pressure test your cooling system. It is like your grandmothers pressure cooker. The boiling point of a liquid can be raised by putting it under pressure. Every cooling system has a radiator cap, which holds between 10-15 psi of pressure. The coolant has a boiling point of 240 degrees. By putting it under pressure you can raise it up to, depending on where you are at sea level, about 270 degrees. It doesn't mean that you want to run the car to that temperature; it means that you have protection to that temperature. We install a pressure pump with a gauge and pressurize the system to 15 psi for about 10-15 minutes. The system must hold that pressure without dropping. If it drops, that means there is a leak. The easiest leak to diagnose would be external, and we should be able to see it leaking from a hose clamp, radiator, a gasket, or water pump seal. Alternatively, the leak could be internal. It is usually harder to find an internal leak, and can be more costly to repair than an external leak. An internal leak could be a head gasket or an intake manifold leaking coolant either into the combustion chamber or into the oil system of the engine. These are the types of problems that can be severe, so AVOID them in the first place!

If the pressure gauge holds pressure, we know that we have a cooling system that has good integrity. We will hook up a machine and back flush the block, the cylinder head, the heater core, and the radiator. By the way, your heater core is inside the dash of your car and looks like a small little radiator. That is what your fan, when you turn on the heat, blows across; as water circulates through it, it blows air across that warmed up heater core, and that is how you get heat in the cab. So we will flush that heater core and radiator until we have all the old antifreeze and corrosive material and particles cleaned out. Then we will drain it and charge it up with a 50/50 mix of the proper level of antifreeze. Finally, we will start the car up, double check our work, make sure that the cooling fans, if it has electric fans, come on at the proper temperature, road test it and deliver to a happy customer!


Consumer Education articles from Dave's Complete Auto Service. Please visit our website at http://www.davescompleteauto.com for more car repair articles and videos. We offer compete car repair, including an in house machine shop, restoration facility, collision center and towing services with locations in Centerville, Utah and Layton, Utah.

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