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‘Check Coolant Level’: What to Know About This Dashboard Notification

Antifreeze overflow filler in engine

Seeing the “Check Coolant Level” warning on your dashboard is often a sign you’re about to have a very bad day. Your engine’s coolant — also known as antifreeze — is a vital fluid that keeps the engine’s temperature regulated, improving efficiency and preventing overheating that could damage the motor.

Not all antifreeze is created equal, and different automakers often require specific formulations to prolong the lives of their particular brand of engines. If you want to keep your motor running in tip-top shape and avoid long-term damage, it’s important to understand the role coolant plays in your car and what to do when the check coolant light comes on.

Remember, NEVER open the radiator cap when the engine is hot. Always wait until the radiator is cool to the touch before opening the cap.

What Does Coolant Do?

Why not just run water in your engine’s radiator to keep things cool? The answer is a little complex. While water would work to a certain degree in an automotive cooling system, you would have to use distilled water — the impurities in tap water would gradually corrode and cause deposits in the engine block, the water pump and the radiator. Plus, even distilled water would freeze in the winter, which would crack the engine block and permanently disable your car.

This is why most engine coolant is water mixed with ethyl glycol, a type of alcohol. Coolant is often called antifreeze because the low freezing temperature of glycol prevents ice from forming, even when the thermometer dips well below freezing. There are also other additives in coolant that work against corrosion and foaming as the liquid is circulated through the car’s system. Finally, dyes are used in store-bought coolants to make it easier to identify which type of coolant and which group of additives are found in your particular system.

Pouring antifreeze into carColor Matching

So how do you pick the right coolant? In the simplest terms, choosing the right antifreeze to add after you see a ‘”Check Coolant Level” light starts with picking the same color that you’re already running. More appropriately, however, you should consult your car’s manual to find the exact name and type of antifreeze your vehicle needs, as similarly-hued jugs of coolant can contain different types of additives.

You don’t have to wait until you see a warning light on your car to change your antifreeze, though. Usually, the coolant in your car is good for roughly 60,000 miles before its additives stop offering peak performance.

If you do encounter a coolant notification from your vehicle, you’ll want to do more than just top off the antifreeze. In this situation, you should find out if your vehicle is leaking or otherwise consuming coolant, as this could indicate a more serious problem.

Check out all the chemical products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to check your coolant level, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.


Benjamin Hunting View All

Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time.  I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.

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