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Why is my coolant disappearing?

Why is my coolant disappearing?

Coolant. Antifreeze. Radiator fluid. While each of these terms may sound very different, the fact is they all describe the same fluids that are critical to keeping your vehicle and its cooling system hydrated. Given its importance, one would think vehicle owners would carefully monitor and maintain the levels and quality of this fluid in their cars and trucks. However, the U.S. Department of Transportation claims that one of the leading causes of breakdowns on our highways is mechanical failures within vehicle cooling systems.

Antifreeze & Cooling System Overview

When it comes to cooling system failures, many problems originate with low fluid levels or poor fluid quality. To understand why it’s important to check, change and replace coolant regularly, we need to take a look at how these fluids work.

Coolant is the fluid—usually bright green in color, but also found in orange, yellow, and red hues—that allows your engine to maintain its optimal temperature by redistributing heat away from the engine through the cooling system. This is accomplished by circulating the coolant from the engine and through your vehicle’s radiator.

You may ask: why does my vehicle need special fluid for this? Couldn’t a jug of water do the same thing? While water is one of the most effective fluids for holding heat, water freezes making it a terrible long-term solution in colder temperatures. To combat the cold, your vehicle most likely requires a 50/50 mix of water and ethylene glycol—giving us the term “antifreeze”.

In addition to lowering the temperature at which the fluid in your radiator will freeze, ethylene glycol improves the temperature at which the fluid in your car or truck will boil—hence the term “coolant”.

Along with keeping your car from freezing in the winter, and your truck from overheating in the summer, your coolant acts as a lubricant for every moving part it touches, including the water pump, which pushes fluid through the engine, cylinder head and radiator. If that wasn’t enough, most coolant contains some type of additives to help prevent costly corrosion within the radiator.

One of the primary factors leading to cooling system failure is a lack of actual coolant within the system, most often attributed to leaks. Since coolant passes through so many different areas within the cooling system, there are numerous possibilities of where a leak may occur. For example, they could start with cracks in the hoses, small holes in the radiator, or issues with the water pump.

Coolant leaks can also happen inside your car. In most cases, a leak inside the car or truck stems from the core component in the heater, but coolant can also blow out as mist from the defroster. Typically, in this case you would smell the coolant before you saw it.  

[Note: Coolant is deadly if swallowed. Not only to humans, but to pets and other animals as well.  Be sure to clean up any leaks or spills thoroughly and wash your hands well after any contact.]

While most leaks are obvious, there are often times you may feel your coolant is simply disappearing. If you have ever found your vehicle missing coolant with no visible leak on the ground or on or around your cooling system, the problem could be a worn out radiator cap, which  allows coolant to actually escape while you’re driving. A blockage in your radiator can lead to problems with coolant flowing properly through the system, making it less visable while in operation. Overheating can also pose a problem with the head gaskets within the engine, causing coolant to escape through your engine’s exhaust.

Even when avoiding leaks and other mishaps, your coolant will eventually start to break down from every day use, preventing it from protecting your cooling system properly. Keeping a careful eye on coolant levels at all times—or having a Sears Auto Center expert check and test the condition of the coolant—will help you detect problems before they escalate. Be sure the consult your vehicle’s owner’s manual for regular maintenance recommendations, including when it’s necessary for a coolant flush.

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