Why Does My Coolant Reservoir Keep Emptying? 

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Why Does My Coolant Reservoir Keep Emptying

When you drive your car, the engine produces a lot of heat. That heat needs to go somewhere, so the cooling system is there to take care of that. The coolant in your car is what helps reduce the temperature of the engine so it does not overheat. There are a number of different coolant systems that come in different types of vehicles and for different makes and models. In most cases, there will be a reservoir with coolant that has a cap on it. This reservoir is there so that you can check to see how much coolant is left in it at any time and add more if it gets low enough.

Why Does My Coolant Reservoir Keep Emptying?

Your thermostat is broken

If your car’s thermostat has been broken for a while, your engine will never reach the proper operating temperature, making it difficult to properly circulate coolant. It’ll be very hard to find leaks in your radiator or hoses since the coolant will never reach those areas, to begin with. If your coolant level is dropping every few days, check your thermostat to make sure it’s not stuck in the open or closed position. If the thermostat is stuck open or broken, you’ll need to replace it as soon as possible to keep your engine from overheating and causing a lot of other damage.

Your radiator is leaking

Your radiator is the main component of your cooling system, so it makes sense that it would be one of the reasons why your coolant level is dropping. To check if your radiator is leaking, you’ll need to open the hood and take a look at the radiator. If you see any drips of coolant coming from your radiator, it’s a good indication that you have a leak which could be caused by a number of different things, including a broken or damaged radiator core, a broken or loose connection on the radiator hoses, a bad or broken pressure cap, or a bad or broken thermostat. The easiest way to tell if your radiator is leaking is to check the level of the coolant. If your level is normal, but you keep seeing drips of coolant coming from the radiator, there’s a good chance that the radiator core has a leak. A leaking radiator will require a full replacement, so you’ll need to schedule an appointment with a mechanic as soon as possible.

Your engine is overheating

If your engine is overheating, it’s a sure sign that your cooling system is having issues. You can easily check the level of your coolant and see if it’s low to check if your engine is overheating. If your radiator is leaking, it will also make it more difficult for your car to properly cool down. Your radiator is what cools your car’s engine, so if there’s a leak in it, your car will have a hard time cooling off. Normally, coolant travels from the engine block and into the radiator, where it travels through the radiator fans and releases the heat into the air. A radiator leak will make it hard for your car’s engine to cool off, so it will keep increasing in temperature.

There’s a leak in your hoses or hose connections

If you’re having trouble figuring out where the leak in your car is coming from, you can use coolant to track it down. The easiest way to check for a leak in your car’s hoses or connections is to pour a little bit of coolant into the radiator, and then check the level of coolant every few days. If you see coolant in your overflow reservoir, you’ll know that there’s a leak in the hoses and connections. To find the exact location of the leak, you’ll have to follow the coolant trail and listen for the sound of the leak.

You have a bad gauge or sensor

The coolant temperature gauge and sensor are what keeps your car’s engine from overheating. If there’s a problem with one of these components, your car’s engine will overheat. If your engine is overheating, your coolant level will be dropping, and you’ll see evidence of this in the coolant gauge and sensor. Overheating can cause extensive damage to your engine, so it’s important to address it as soon as possible. If you suspect that your gauge or sensor may be faulty, you should visit a mechanic to have it checked.

How To Deal With A Depleted Coolant Reservoir?

Check for Leaks

This might sound obvious, but the first thing you should do is make sure you’re not simply losing coolant. If the reservoir is low, you can be pretty sure there’s a leak in the system somewhere. Check the tires for signs of a leak, and look underneath the car for drips or puddles, too. If you notice a leak, mark the location of it with something that won’t wash away in the rain. This will help you diagnose the problem. If you don’t find a leak, there could be another problem causing the low coolant level. For example, the thermostat might be stuck open, or the radiator fins might be clogged. If you’re sure that you’re not simply losing coolant, then the next thing to check is the radiator pressure cap.

Add Coolant

Most cars have a low coolant warning light that will illuminate if the reservoir is almost empty. This is a good time to add some coolant. If you don’t have any on hand, you can buy a bottle of premixed coolant at any auto parts store. If you don’t have time to stop at the store, you can use a 50/50 mixture of water and antifreeze. Just remember that you’ll have to add more coolant again when you get to a store. As you’re adding the coolant, be sure to check the antifreeze level in the radiator. If it’s too low, you might need to add more. In fact, we recommend adding a full container of coolant even if the level is just a little low.

Run the Fan Constantly

Some cars have a pressure-activated cooling system. In these cases, the cooling fan doesn’t switch on automatically when the coolant level drops too low. You can help the situation by keeping the fan on. In some cars, you might have to turn the fan on manually. If you have a conventional car with a radiator, there is usually a switch on the radiator that turns the fan on. Look for a switch that has “fan” written on it. If you have a sports car with an electric cooling system, the fan should turn on automatically when the coolant level drops too low. If not, you may need to reset the computer.

Mix Water and Antifreeze

You can try mixing water and antifreeze, which will bring the level up. Again, you’ll have to add more coolant when you get to a store. If you don’t have the time to make your own mixture, you can buy a premixed coolant that includes water. This will bring the level up, but it’s not a permanent fix. You’ll need to add more coolant later. You might want to add a water softener to the mixture, too. The water in your area might contain minerals that can clog the cooling system.

Get Professional Help

If you’ve tried all the above methods but nothing seems to clear up the problem, it might be time to get professional help. There may be something wrong with your cooling system that you’re not able to fix. In this case, it’s best to leave the repairs to the pros. If you’re not sure if you need a new radiator or thermostat, have a mechanic take a look at it. They’ll be able to tell you what’s wrong, and they’ll be able to recommend a solution. The mechanic will probably offer to flush the system and replace the radiator. This is a good idea since the mineral deposits that can clog the radiator can also get into the rest of the system.

What To Do If Your Coolant Reservoir Keeps Running Out?

  • If your coolant reservoir keeps running out of coolant, there could be a few different issues, but the first thing you want to do is make sure you are adding enough coolant to the system.
  •  If you are, but it is still happening, you can check the thermostat to see if it is broken.
  •  If the thermostat is faulty, you will want to replace it before the coolant runs out. Another possible cause of a coolant reservoir constantly running out is a leak in the system. 
  • You will want to have this fixed as soon as possible to avoid engine damage from overheating.


A coolant reservoir is basically a container that holds the engine coolant in your car when it uses a liquid type of coolant. This coolant is commonly a mixture of water, ethylene glycol, and sometimes some other additives designed to help protect the engine. The coolant reservoir is where you can check how much coolant is in your car at any time. This makes it easy to add more coolant when needed or check and see if you need to add more. 

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