How to Clean a Coolant Reservoir – All You Need to Know

While inspecting your coolant level, check the status of your car’s coolant reservoir. If you find it dirty and filled with deposits, it’s time to clean it. If you’re not sure how to do it, don’t worry. Here’s our complete guide on how to clean a coolant reservoir.   

What Is a Coolant Reservoir?  

The coolant reservoir or overflow tank is where the excess coolant produced because of the engine’s heat is stored. When your car’s engine heats up, the warmth makes the coolant expand. This expanded coolant overflows into the coolant reservoir, and when your car cools down, it is sucked back into the radiator.

The coolant reservoir plays a vital role in this cycle, and therefore, any damage or harm to the reservoir can cause your car to overheat. That’s why it’s important to keep the coolant reservoir in its best condition all the time.

Why Should You Clean Your Coolant Reservoir?

Over time, your coolant reservoir tank can be filled with dirt, mud, and sludge. These contaminants deposited inside the reservoir can affect the quality of the coolant. This, in turn, can negatively affect the car’s performance. Therefore, make sure you check the coolant reservoir’s status during your car maintenance schedule or while changing the coolant. If you notice it is dirty and yellowish, clean it as soon as possible.    

How to Clean a Coolant Reservoir

We’ve mentioned the important steps in cleaning your coolant reservoir below. Follow these steps to clean it without any hassle.  

Step 1   

Before you start the cleaning process, make sure the engine is cool. Turn off the engine and wait for at least two hours before touching the coolant reservoir.   

Step 2  

Disconnect the hoses and remove the coolant reservoir tank. If the tank still contains any fluid, transfer it to another bucket. Now, closely inspect the reservoir and check its condition.   

Step 3  

To remove the deeply embedded dirt, you should soak the reservoir in a container having bleach, water, and dishwashing liquid. Now place the reservoir into this container and allow it to sit for a few hours, or you can also let it stay overnight. Make sure you remove the reservoir’s cap to allow the solution to enter and loosen the dirt.   

Step 4  

Scrub the reservoir’s outer part to remove the dirt using a brush. Repeat the process till the pale-yellow color disappears.   

Step 5  

To clean the inner part. Clear all the liquid present inside and use a brush to clean it. Next, rinse it with a high-pressure hose. Repeat the process until you see a noticeable change of color. Once you’re satisfied with the result, place the reservoir back as it was.   

How Do I Know If My Coolant Reservoir Is Clogged?

To know whether the coolant reservoir has become blocked, drain the radiator and inspect the coolant flow. Ideally, the flow should be steady. If the flow is slow or varying, the car has a clogged radiator.

The following are some signs that indicate a clogged radiator.

• The engine is getting overheated often.
• The coolant level is low.
• There is a leakage of coolant.
• AC vents give out warm air.
• Defective radiator hoses.
• Smoke from below the hood.
• Rusty or dirty coolant.

Why Is My Coolant Reservoir Dirty?

These are some reasons why the coolant reservoir has turned dirty.

• Polluted coolant: Having a broken cylinder head or a dirty head gasket can mix the coolant and oil, forming sludge. A crack in the system can pollute the coolant with transmission fluid.
• Corrosion: it happens when unwanted coolant chemically reacts with metal surfaces, creating reddish deposits that appear as slush.
• Removal of additives: Coolant comprises a base mixed with water and additives. The base should ideally offer freeze and boil-over protection— the additives shield against corrosion, scaling, and cavitation. A mixture of incorrect coolants can cause the additives to be removed from the solution and form a sludge.

Is It Normal for the Coolant Reservoir to Be Empty?

No, it isn’t normal for the coolant reservoir to be empty, as your coolant system can’t draw in additional coolant when it wants it. It can cause overheating. You can refill the reservoir with fresh coolant, but you must also find out where that coolant went.

Can a car run without a coolant reservoir?

No, you must never drive your car without coolant. That’s because driving the car without coolant can result in the car becoming inoperative within a few minutes. If the car becomes damaged, you have to get the engine replaced before driving again.

What happens if your coolant reservoir is clogged?

A clogged radiator means that there’s an overflow of the coolant.

Can I pour water into the coolant reservoir?

Yes, you can pour water into the radiator if the engine is getting overheated or if the coolant reservoir is empty. But you must do this only when there’s no other choice. Also, this is effective only for shorter distances.