How Much Coolant Should Be in the Overflow Tank?

Overflow Tank

The purpose of a coolant overflow tank is to store coolant that has been displaced from the radiator. This can happen as the temperature of the coolant rises and causes it to expand. As the coolant gets colder, it contracts and displaces some of the coolants back into the radiator. This process happens continually as your engine runs and helps to regulate the temperature of the engine coolant.

The main reason you need to check your coolant level often is that if there isn’t enough coolant in the overflow tank, your engine could overheat. That’s why it’s important to know how much coolant should be in the overflow tank. Here’s a quick guide on how to check your coolant level and what to do if it’s low.

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How to Check Your Coolant Levels?

To check your coolant level, first, find the overflow tank. It’s usually located near the radiator and has a white cap with a green handle. Once you’ve found it, unscrew the cap and look at the liquid level inside. If it’s below the “Full” line, then you’ll need to add more coolant.

You can buy pre-mixed coolant at most auto parts stores, or you can mix your own using distilled water and antifreeze concentrate. If you go with the latter option, be sure to use a 50/50 mix of anti-freeze and water. Any less antifreeze and your engine could freeze in cold weather; any more, and it might not dissipate heat well enough in hot weather.

What to Do If It’s Low?

If you find that your coolant level is low, add more until it reaches the “Full” line on the overflow tank. Once you’ve done that, screw the cap back on tight and start up your engine. Let it idle for a few minutes so that the new coolant can circulate throughout your system, then turn off your engine and double-check the overflow tank one last time to make sure that the level hasn’t dropped again.

Why Maintaining Right Level is Important?

It’s important to maintain the right coolant level in your overflow tank because if the level gets too low, your engine could overheat. This could cause serious damage to your engine and might even lead to a complete breakdown. So, be sure to check your coolant level often and top it off as needed. By doing so, you can help extend the life of your engine and avoid costly repairs down the road.


It’s important to check your coolant level often and top it off if necessary. Doing so will help prevent your engine from overheating. Be sure to use a 50/50 mix of distilled water and antifreeze concentrate when adding new coolant to your system.

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