Losing Coolant Only When Driving: What To Do? (Explained!)

One of the most critical components of a vehicle is the cooling system. A vehicle’s cooling system will allow the engine to work while keeping its working temperature inside the threshold limits. There is also a chance that the pressurized system will not be maintained. 

If there is a leak in your vehicle while running, your vehicle’s engine can overheat. In addition to that, your vehicle can also have damages that will need to be repaired soon. So if your vehicle is losing coolant while driving it and you are bothered by it, you are on the right page. 

This article will discuss why you are losing coolant in your vehicle and what you have to do. Let us get started. 

Losing Coolant Only When Driving

Why Does My Car Leak Coolant Only When I Drive?

The cooling system of every vehicle is a closed section, hoses, and cylinders. The engine and the radiator are also part of the cooling system. In any of these areas, leaks can happen. 

These leaks can cause dripping of the coolant when driving. The causes of the leaks can be external leaks, radiator leaks, radiator cap leaks, blown head gasket, failed water pump, and issues with the coolant tank extension. 

1. There Are External Leaks.

The coolant fluid will move into the engine so that it can get heat. The heat will then be sent back into the radiator to cool before going out of the engine. If there are leaks in these parts, this is then viewed as an external leak, leading to dripping if the vehicle is running. 

The external vehicle coolant spill is very simple to analyze. You do not need devices to test for anything. You need to keep an eye for any indication of breaks.

2. There Are Radiator Leaks.

The radiator hose is responsible for the external coolant spills if your vehicle is running. The elastic hoses can degrade and weaken over time, and they can also burst. 

In addition, the connections between hoses and some other coolant systems can break. And if there are free clasps, it can cause fluid coolant to leak. 

3. There Are Radiator Cap Leaks.

The radiator cap is saddled with keeping the ideal pressure needed to move the coolant water mixture. If there is a loss of pressure, the coolant fluid cannot travel into the system. The radiator of your vehicle is known to be a pressurized system. 

This allows a hot fluid from the engine to travel into the arrangement of the cylinder in the radiator. Travel can also reduce heat, and it makes the engine from heating. If the radiator cap is leaking, the pressure of the radiator cannot keep up. 

4. There Is A Blown Head Gasket.

The head gasket of your vehicle is a vital part of the condition of your engine. If your head gasket blows, you might not notice it for a while. You can even drive a few miles before you notice that there is a problem. 

This is because the head gasket deals with a broad scope of temperatures. This is in between the cylinder head and the engine block. If this starts to leak, it is known to blow. 

If that happens, you cannot keep the motor oil and the coolant separate. This can cause severe damages to your engine.

5. There Is A Failed Water Pump.

The water pump is an essential thing in keeping the coolant flowing in through the cooling framework. This has a belt in the lower part of the engine and is close to the drive belts. It also has a lower house of radiator. 

The hose can lose for some time. It can also get rusted. It can also experience a type of external damage.

6. There Are Issues With The Coolant Extension Tank.

The vehicles have an extension tank. And this can circulate into the radiator. Most of the extension tanks are in plastic form, and it is located close to the engine. 

It usually has a radiator with an elastic hose. This hose will get the coolant and deliver it to the radiator and vice versa. This is while the engine is warming or cooling down. 

What To Do When You Have This Issue?

It is recommended to have your radiator hose examined. Look for any splits, swells, openings, or damaged hoses. If there are damaged hoses, have them replaced immediately. 

Any damages to the radiator can prompt an external coolant leak while you are driving. If you leak your radiator, have the radiator checked. You also have to drive to the nearest service center to perform a pressure test into the radiator cap. 

You can also check on the vehicle user manual and check the cap of the radiator. If there are damages to the water hose, it can also be due to tear and wear. You will need to replace them so that you can avoid any continuous leaking. 

You can also avoid the leaking of coolant when driving your vehicle by adhering to the required quantity of the coolant recommended for the extension tank. You also have to follow the standard maintenance plan involved in changing the coolant of your radiator. The old coolant will then go stale. 

If this happens, it can become acidic, and the aluminum can also destroy it in your radiator. You also need to visit a mechanic and have the mechanic identify the problem. 

Can Coolant Leak While Driving?

Yes. One of the common reasons your vehicle is leaking coolant while driving is because the engine is hot and under pressure while running and can cause leaks. 

The causes of the coolant leaks if your engine is running can be a cracked coolant hose, a leak in your radiator, a leak in the coolant radiator cap, and a blown head gasket. The coolant can escape from a cracked hose or a leaking gasket if your engine is running. In addition, the coolant can pump under pressure around the engine.


In summary, people have been noticing that their coolant is leaking when they are driving. This bothers car owners because coolant prevents your engine from overheating.

This article will serve as your guide. Use this article for any issues with your coolant leaks. There are solutions for the leaks.



Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more