With all that air, fuel, and fire stuff going on in its engine, your vehicle needs something to help it keep a cool (cylinder) head! Because water is usually cheap, plentiful, and readily available, auto manufacturers have found it to be the simplest answer to the problem.
A few have found that air is even cheaper and more abundant; they designed the air-cooled engines on the old Volkswagens, but aside from some VW bugs and air-cooled Porsches that are still on the road, there are few air-cooled vehicles available in the United States these days.
Of course, nothing is as simple as it seems. Automakers have added some gizmos to keep the water in the engine from boiling too easily: a water pump, fan, radiator, thermostat, and coolant. There’s also a transmission cooler to keep the transmission from overheating and an air-conditioner to keep you from overheating.
Together they comprise your vehicle’s cooling system . The cooling system is highly efficient. It usually requires almost no work to keep it operating — just a watchful eye for leaks and an occasional check or change of coolant.
Of course, some vehicles have more complicated systems or variations on the theme, but in general, if you understand the way the basic cooling system works, you should have little trouble dealing with the one in your vehicle. Whether you do the work yourself or have it done professionally, keeping the cooling system in good shape will go a long way toward “keeping your cool” when things heat up on the road.
The cooling system. This chapter explores the cooling system part by part. shows you what to do if your vehicle overheats and how to maintain and troubleshoot the cooling system and make easy repairs. helps you get out of trouble if your car overheats on the road. Whenever you encounter a term set in this font, you’ll find it defined in the glossary in Appendix A.
Most coolants contain about 95 percent ethylene glycol, a chemical that stops water from freezing or boiling even in extreme temperatures. (Ethylene glycol is toxic; there are nontoxic coolants that contain propylene glycol instead.
In addition to the glycol, coolant also contains rust, corrosion, and foaming inhibitors, so coolant does more than just keep the water in the system in a liquid state: It also helps to prevent the formation of rust on the metal surfaces of the engine and the radiator, lubricates the water pump, and keeps the liquid from foaming as it circulates through the system.
Since the early 1960s, auto manufacturers have designed the cooling systems of most vehicles for a 5 0/50 mixture of ethylene glycol and water, which is still generally considered the proper proportion of coolant to water for the cooling systems of most vehicles.
(I often refer to the coolant and water mixture as “liquid” . Today’s engines require specially formulated coolants that are safe for aluminum components. There are long-life (sometimes called “extended life”) coolants with organic acid rust and corrosion inhibitors that promise to last for as long as five years.
Automakers use some of these coolants as original fluid in new vehicle radiators made of aluminum (they can’t be used in anything except aluminum radiators). Due to differences in Japanese, Korean, European, and American compounds, you can shorten coolant life by putting the wrong stuff in your vehicle’s cooling system.
So make sure that you use the automaker’s recommended coolant to ensure the longest life and best protection for your vehicle. If your cooling system is operating properly, you shouldn’t have to keep adding liquid to it. shows you how to check the level and condition of the liquid in the cooling system, and shows you how to add liquid or flush the system and replace the liquid in it.