Auto Repair - Other
An automotive cooling system design.

Cooling System Problems

An automotive cooling system design.
Dan Ferrell's image for:
"Cooling System Problems"
Caption: An automotive cooling system design.
Image by: Photo courtesy of Vibby on Wikimedia.

Trying to find the cause of cooling system problems in your vehicle can be like trying to solve a puzzle at times. However, coolant leaks, engine overheating and overcooling are three of the most common issues to affect this system. Thus, a professional mechanic knows there are some specific components and maintenance issues associated with one or more of these conditions. This simple guide will tell you which parts and operating states are the most likely to be causing trouble, so that you can fix your cooling system faster.

Cooling system leaks

This is one of the most common problems affecting a vehicle's cooling system. As components wear out, leaks begin to make their way through weakened joints and mating surfaces. In most cases, a simple visual inspection can reveal the source of the problem.

There's usually a telltale wet spot around the engine, an accessory or on the floor—where you park your vehicle—that may tell you where that leak is coming from. Look for darkened areas around the radiator or heater core; a wet area around the hose of one of these components, the water pump or the engine block. However, if you're sure you are dealing with a system leak but can't seem to find the culprit, you might be dealing with an internal problem, such as a cracked water jacket or cylinder head gasket. In this case, it is a good idea to take your vehicle to a service shop for a cooling system pressure test to find the source.

Engine operates above normal temperature

Vehicle engines are designed to operate at a temperature that oscillates between 180 and 210 degrees Fahrenheit (80 and 100 degrees Celsius). Although cooling system leaks are a common cause of engine overheating, they are not the only ones. Check the coolant level in your system and add the recommended antifreeze-mixed with 50 percent distilled water-to the reservoir to bring the coolant to the correct level, if necessary. Also, look for a loose or worn out fan belt; a radiator outer face covered with dead leaves, bugs and other debris; a failing and/or noisy water pump; a failing radiator fan or a thermostat stuck in the closed position.

A particular problem that many car owners fail to prevent is rust buildup inside the radiator. Over time, rust will clog internal core tubes, severely restricting coolant flow and increasing engine-operating temperature. If left unattended, rust will reach, corrode and destroy the water pump and engine core plugs as well. You can prevent rust buildup by performing a radiator flush when replacing the coolant in the system. This is usually done every two years, when corrosion inhibitors in the antifreeze begin to lose their working properties. Consult your car owner's manual for the recommended coolant change intervals for your particular car make and model.

Engine operates bellow normal temperature

Although leaks and overheating are two of the most serious problems affecting a car's cooling system, overcooling can be just as bad. Overcooling not only makes it much more difficult for your engine to reach operating temperature, but also leads to bad engine performance, an increase in fuel consumption and parts wear. When dealing with an overcooling engine, look for a radiator fan operating continuously. This may be due to a shorted fan switch or a stuck fan clutch, if your vehicle is equipped with it. Also, check if your thermostat is stuck in the open position, allowing the coolant to circulate continuously between the engine and radiator, and preventing your engine from reaching an adequate temperature.

Of course, the on-board diagnostic (OBD) system in your car can help you repair the cooling system as well, depending on your vehicle make and model. The OBD system or car computer can store a trouble code due to a failing sensor-like the coolant temperature sensor and oil temperature sensor-or some other cooling related electrical circuit. Many auto parts stores now will retrieve this trouble code for you, free of charge, if your car's check engine light has been activated.

Coolant leaks, engine overheating and overcooling are the most likely cooling system problems you will have to deal with when the system fails to work as it should. However, as you already learned, there are some common parts and performance issues associated with these problems. Whatever the cause, keep this simple guide handy to steer you in the right direction and help you get your cooling system, and your car, back in shape and on the road.

More about this author: Dan Ferrell

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