6 Symptoms of a Bad Coolant Overflow Tank
Coolant overflow tanks are designed to capture excess coolant that is released from the radiator due to pressure built up by heat. They work similarly to an expansion tank in a water heater.
As you may know, a heavily used engine heats up very quickly. Oil alone is not enough to cool the engine components. The engine relies on coolant to keep from overheating in these high performance situations. As this heat is generated, the coolant absorbs all the heat and keeps the engine cool.
So what happens if your coolant overflow tank cracks, breaks, or overflows? Below are some common symptoms that a faulty coolant expansion tank can cause.
That little plastic container next to your radiator probably doesn’t seem important, but it plays a vital role in the safe operation of your engine. When your radiator coolant overflow tank starts to fail, it can cause a series of problems, from mysterious leaks to deadly overheating issues. Learn how to recognize the warning signs of a damaged expansion tank before your engine overheats and leaves you stranded. Fortunately, replacing a coolant overflow tank isn’t too expensive.
Common Signs of a Failed Coolant Overflow Tank
Here are the 6 most common signs that your radiator overflow tank is faulty.
1) Coolant Leak
If your radiator coolant overflow tank is damaged or cracked, it can leak coolant. If the overflow tank is too old and worn, it can sometimes crack. You should notice small puddles or drips of coolant on your garage floor or driveway.
Caution: Coolant is extremely harmful to dogs and cats. If you notice coolant leaking on your floor, have them clean it up immediately so your pet doesn’t have to do it. There have been many cases of dogs and cats becoming seriously ill or dying from ingesting engine coolant.
2) Cracks or clouding in the overflow tank
The plastic used to manufacture radiator overflow tanks becomes brittle over time and is prone to cracking. Even a small hairline crack can lead to a significant engine coolant leak. Visible cracks in the tank, especially near the mounting points, indicate a need for replacement. Cloudiness or dirt inside the tank indicates corrosion or deterioration of the plastic due to aging or chemical reactions. When the plastic breaks, small leaks can occur even without visible cracks. It only takes a minute to check for cracks and cloudiness when the engine is cold, and can easily prevent expensive engine damage.
3) Coolant Odor
In addition to coolant leaks, the front of the car will emit a distinctive smell of coolant. If it gets bad, it can even spread throughout the entire interior of the car.
It’s not the worst smell in the world (it’s a bit sweet), but it’s not something you want to smell for a long time. So if you smell this warning signal, check the condition of your overflow tank and replace it as soon as possible.
4) Engine overheating
Since the role of coolant is to cool the engine when it is overloaded, a leak (or a broken radiator hose) could mean that there is not enough coolant circulating through the engine to cool it sufficiently.
5) Low coolant level
Check the coolant level in the radiator coolant overflow tank, and if it is low, coolant is slowly evaporating or leaking. Even people who normally don’t notice leaks may notice a small leak that is hard to notice from the outside. To be sure, you should check the coolant level to see if there is a leak. The overflow tank lid is often the source of the leak.
6) Bubbles in the overflow container
Air bubbles in the coolant reservoir usually indicate a problem with the cooling system. Air bubbles mean that combustion gases from the engine cylinders are leaking into the coolant, often through a defective head gasket. It’s unlikely that you’ll have air bubbles in your coolant expansion tank, but it could simply be an indication that there’s a crack or hole somewhere in the tank that’s letting air in.
