8 Reasons Your Car Is Leaking Coolant While Not Running

• Mohamed Shamiq

Updated on September 14, 2022

If you see any liquid dripping under your car, it is not a good sign. Antifreeze leaks are not that rare. With a ton of liquids running through your car, you will eventually run into some trouble. You need not panic about leaking fluids, as long as you have the knowledge to deal with it. To deal with a coolant leak, you need to know the reasons why your car is leaking while not running.

• What is antifreeze?
• How to identify a coolant leak?
• What causes coolant leaks?
• What happens if you drive without coolant?

What Is Antifreeze?

An engine consists of dozens of moving parts. When these metal components rub against each other, it builds up a lot of heat. This heat created by friction builds up and can overheat your engine.

The solution for this is your coolant. The coolant circulates your engine while absorbing all the heat produced by it. Coolant is commonly referred to as antifreeze. Though they are considered the same thing they aren’t.

Antifreeze is actually a concentrated form of coolant. For it to be used in your engine it needs to be diluted with water. When antifreeze is diluted with water, it is known as coolant.

How Does It Work

The coolant is stored in a reservoir. From there it is pumped to the engine. As the coolant flows around the engine it will absorb all the heat produced by the engine. By doing so it will keep the engine safe.

Now the hot coolant moves to the radiator. Inside the radiator, the airflow reduces the temperature of the coolant. Once the coolant is at a lower temperature, it flows back into the engine to absorb the heat from the engine.

What Is Coolant Made From?

Coolant is a water-based liquid. But the addition of antifreeze adds a lot of positive properties to the liquid. The antifreeze keeps the water from freezing at low temperatures. It also protects your engine from rust.

When you looking what coolant is made of, what you are really looking for is antifreeze. Though there are dozens of varieties, almost all coolants in the market are derived from a base chemical Ethylene Glycol. Various other chemicals are added to this to provide other beneficial properties.

Some believe that you can use water as a coolant. But actually, it is not such a good idea. Water can freeze when the temperature drops. Ice crystals can damage the water pump. If it’s completely frozen, it wouldn’t be able to flow at all.

If you live in a place where sub-zero temperatures are rare, you still won’t be able to use water as a coolant. This is because of the minerals in the water. These minerals deposit along the path that the coolant takes. These minerals end up damaging the engine.

Other than these, water will also contribute to rusting. Unlike coolant which will protect your engine from rust.

How To Identify A Coolant Leak?

If you suspect that you are running out of coolant due to a leak, there is some way in which you can confirm, whether your car is leaking coolant.

Look For A Puddle

Usually, when liquids are leaking they tend to leave a puddle of fluids where they were parked. This is the first thing that you look for. Before looking into reasons your car is leaking coolant while not running, you first need to make sure that the liquid that forms the puddle is in fact your car’s coolant.

With many liquids running through your car, identifying is not easy. Due to this, the liquids in your car have colors assigned to them.

It is not that simple though. In this case, the coolant does not have a specific color. A few years back there was only one type of coolant. This was dyed green. With improvements in technology, we have a lot of different types of coolants nowadays. So now there is no standard color for the coolant.

But usually, coolant is dyed in a bright color. This is to make it easy to check coolant levels in your reservoir. There is a chance that it could get discolored after accumulating dirt and debris from the cooling system. So there are no guarenttes.

Another option is to check the texture. Coolant is a water-based fluid. Most other fluids in your car are primarily used as a lubricant. Therefore they have an oily texture. This is a handy way to confirm that the liquid leaked is coolant.

Observe The Reservoir

On some occasions, a coolant leak is not going to drip down to the floor. There is a chance that the coolant is leaking into another component around your engine. If you run out of coolant all of a sudden, it is probably a leak. But how do you confirm it if there is no evidence except for the low coolant level?

Pour water into the coolant reservoir. Observe for a while for any drops in your coolant level. If you do not see any changes, get your engine running. This will start pumping the coolant or in this case the water throughout the engine.

Again, keep an eye out for the fluid levels. If you see the coolant dropping steadily it would mean that your coolant is leaking.

Here is the bad news, whether you are right about the leak or wrong, if you test for a coolant leak using this method, you should consider getting your coolant flushed. But if you notice that there is a leak in the system, in that case, you need to fix the leak before performing a coolant flush.

What Causes Coolant Leaks While Parked?

Usually, when liquids are leaking from your car it can be due to one of many possibilities. Your coolant circulates the entire engine and gets back to the radiator. This is not a small journey.

Any cracks, holes, wear of seals or loose fittings could cause your coolant to leak. If there is any sort of damage along the path of the coolant, it could cause it to leak. When you are looking at reasons why your car is leaking coolant while not running, there is a long list of potential suspects.

1. Damaged Water Pump

Coolant needs to be supplied with a certain amount of energy to keep it flowing. This is where the water pump comes in. It pressurizes and pumps the coolant so that it can circulate the engine.

Without a functioning water pump, your coolant is not going to be effective. It doesn’t matter if you fill it to the brim, without the force of the water pump, the coolant cannot circulate. This will cause your engine to overheat.

There can be multiple causes why your water pump is not working. For the coolant to leak through the water pump, it should have external damage. Usually, it is the connection between the water pump and the radiator hose that causes the leak.

It is almost impossible to salvage a damaged water pump. So you definitely need to replace it. Water pump replacements cost between $300 to $500. Half of the cost is due to labor charges.

2. Radiator Leaks

The radiator is another point that could be the reason your car is leaking coolant while not running. The radiator is constantly subjected to pressure and heat. This puts a lot of stress on the radiator and the junctions in which hoses are connected to the radiator.

In radiator leaks, often the areas where hoses are connected to the radiator tend to be the weak spot. Wear and tear allow antifreeze to leak out of these worn-out seals. Corrosion could also have similar effects. In modern cars, which use modern coolants, corrosion is rare.

Depending on where the leak is in your radiator, the repair procedure will change. There is a chance that you will be able to repair the existing radiator. If so, the repair costs aren’t going to be high.

3. Cracked Hoses

Hoses are what transports the coolant from one place to another. They are subjected to high temperatures with pressurized coolant flowing through them. Though the hoses are built to take this abuse, with time hoses tend to wear out.

Worn hoses might have tiny holes in them. This could allow the coolant to seep out. Hoses also tend to become brittle with time. So you might see cracks in the hose as well.

It is rare to see hoses disconnected when the car is parked. It is possible that it could happen while driving, but if your car is leaking coolant while parked due to radiator hoses, you might have to consider replacing your hoses.

4. Loose Clamps

Radiator hoses are connected to the radiator using clamps. These clamps go around the hose and are tightened in order to seal the connection between the hoses and the radiator.

If you use low-quality clamps, they can rust. When your clamp is not properly attached to the hose, it will not create a proper seal. This will allow the coolant to escape through those loose seals causing a coolant leak.

The good news is that this is a cheap fix. All you need to do is replace a few clamps. Make sure to use good-quality clamps so they do not corrode again.

5. Damaged Radiator Cap

The radiator cap maintains the pressure in the system. If the pressure is too high, it releases the pressure. It contains a valve that routes the coolant back to the reservoir if the pressure is found to be too high.

A damaged or failed radiator cap, will not be able to accomplish its task. The radiator cap tends to get stuck. When this happens the valve is unable to open and relieve the pressure. This would allow the coolant to flow at a higher pressure.

This is one of the worst things that could happen to your cooling system. If the pressure rises in the system, as the fluid flows it can damage the components.

On the other hand, if the radiator cap is unable to close that poses a different problem. This could cause the coolant to flow into the reservoir at a higher rate than normal, causing it to overflow.

6. Damaged Heater Core

The hot coolant flows through the heater core. The heat is then taken from the coolant and blown through your ventilation system when you switch on your heater.

It faces the same issues as the radiator. If the reason your car is leaking coolant while not running is the heater core, you will see coolant leaks in the passenger side of the engine.

The best solution for this is to replace the heater core. A unit built with aluminum and a core made of copper is the best replacement. These manage to last longer.

7. Damaged Coolant Reservoir

Cracks or punctures in the coolant reservoir will cause your coolant to leak. But they are not common. They rarely happen naturally. A crack or a hole in your coolant can only be caused by an external force hitting the reservoir.

Thankfully, fixing cracks or punctures in the reservoir is not hard. Use a silicone sealer to patch it up. If the damage cannot be sealed you will have to replace the coolant reservoir.

8. Head Gasket Damage

The head gasket is a vital component in your engine. If your head gasket is damaged, leaking coolant is the least of your worries. But leaking coolant can be a good indicator for head gasket damage.

The head gasket assists in the flow of coolant and engine oil in the engine. A damaged head gasket would result in both engine oil and coolant entering the combustion chamber. This could critically damage your engine.

A coolant leak could be an indicator of this. Another indicator is white fumes through the exhaust. When coolant burns inside the engine it will turn into steam and exit through the exhaust. This steam appears as white smoke.

These are the common reasons your car is leaking coolant while not running.

What Happens If You Ignore Reasons Your Car Is Leaking Coolant While Not Running?

Whenever you notice a problem in your car, you need to take action towards repairing it. You will still be able to drive when your car is low on fluids, but you’d be risking damage to major components of the car.

This is true with coolant as well. Just like any other fluid, coolant is crucial to keep your car functioning. If you ignore the reasons your car is leaking coolant while not running, you will get the problems fixed. Eventually, your coolant will run out through that leak.

Here’s what will happen if you drive with low coolant levels.

Engine Overheating

This is not a surprise. The coolant’s primary task is to prevent the engine from overheating. Without the coolant, the engine will continuously rise in temperature and overheat.

When the engine overheats, the damage is certain. The first and most common part to get damaged is the head gasket. As mentioned earlier, a blown head gasket will allow engine oil and coolant into the combustion chamber. Ultimately, it will lead to irreversible damage.

Malfunctioning AC

The heater core draws energy from the coolant. Without coolant, your engine will overheat but the what won’t be transferred to the heater core. So even if you crank up the temperature in your ventilation system, it will not show an increase in temperature.

Damaged Water Pump

With or without coolant, the water pump will function when the engine is on. When there is no coolant, the water pump will operate without any resistance to slow it down. If it works without coolant for a long time, it will be damaged.

FAQs

Here are some of the most common questions regarding the reasons why your car is leaking coolant while not running.

How To Identify A Coolant Leak In The Car?

Often when your car is suffering from a coolant leak, it will drip down to form a puddle when parked. If you know how different one liquid in your car is from the other, you should be able to identify what liquid has been leaking in your car.

If the leak is caused due to damaged head gasket, you will see white smoke coming out of the exhaust. Other than that, you have to look for general symptoms of low coolant to identify a coolant leak.

How Much Does It Cost To Fix A Coolant Leak?

We cannot tell you exactly how much it is going to cost you to fix your coolant leak. It all depends on the reason your car is leaking coolant while parked.

A radiator replacement could cost you $200 to $1000 depending on your car. A damaged head gasket could cost anywhere from $1000 to $2000 or more. While repairing a coolant reservoir is going to cost less than $100. The actual cost to fix a coolant leak depends on why your coolant is leaking.

Can A Coolant Leak Damage Other Components?

A coolant leak will cause a lack of coolant in your car. This will damage several components. Apart from that if the coolant leaks into the engine, it will damage the engine beyond repair.

Is It Okay To Use Water Instead Of Coolant?

Water can be used as a coolant, but only during emergencies. If you do use it because you are out of coolant, then you have to flush your cooling system when possible.

This is only permissible when the climate is warm. In cold temperatures, water will freeze. Even if it doesn’t become completely solid, tiny frozen ice crystals can damage your cooling system.

How Often Should You Replace The Coolant?

The exact number will differ according to the coolant you use and your manufacturer’s suggestion. But generally, the number is 30,000 miles. Every 30,000 miles you need to completely flush out your existing coolant and replace it with a new one.

Even though the replacement window comes every 30,000 miles, you need to regularly check coolant levels and top it off as necessary.

How To Distinguish Leaked Coolant?

Usually, fluid leaks can be easily identified using color. In the case of coolant, there is no such thing as a standard color. You might find it green, orange, pink or any other color. Even though there are a variety of colors, coolant is often dyed using a bright color.

Other than the color the best way to distinguish coolant is the texture. While most liquids have an oily texture coolant, since the coolant is mostly made out of the water, you will notice a difference in texture.

Conclusion

No matter how careful you are with your car, eventually, you will run into some trouble with it. Whether you have faced it before or not, it is best to be ready for the next time.

Coolant leaks are quite a common problem in cars. When you look at the importance of coolant and what happens when you drive without it, leaking coolants might cause you to panic. But fortunately, if you notice the signs fast enough, you can get out of the problem without suffering a lot of damage.

The coolant circulates through a bug area and goes through many components. A failure at one of these parts could be the reason your car is leaking coolant while not running.

Depending on the component that is damaged the symptoms might vary. But the best way to check the source of the leak is a physical inspection.

If you can find the leak, depending on the experience you have and the complexity of the repair, you can either do it yourself or take it to a professional. If you do not find the source of the leak, and you notice that your coolant is running out faster than usual, then you have to hire a mechanic and get your car checked.

Never ignore reasons why your is leaking coolant while not running. You might be able to drive your car around for a while, but driving with a coolant leak is never a good idea.

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