Coolant Shooting Out Of Radiator [5 Easy Solutions]

The air pocket in the engine block is the main culprit for coolant shooting out of radiator. Besides, a faulty radiator cap, a cracked cylinder head, and a bad thermostat are other caveats that cause the coolant to overflow out of the radiator. 

coolant shooting out of radiator

Once you address and deal with those issues, you can stop the coolant leak. And no coolant leak means a smooth engine, which improves the performance of your vehicle. Throughout this guide, we will break down every issue we mentioned. So, let’s get started to discover the solutions. 

Coolant Shooting Out Of Radiator [5 Easy Solutions]

This chapter will walk you through the troubleshooting steps to fix the coolant shooting-out issues. 

Note: You can also read how to fix Coolant Leak front passenger side tire

01. Air Pocket In The Engine Block

If you make a replacement recently like the thermostat or anything that involves draining the coolant, it may create an air pocket.

You may just add coolant and start driving your car. As a result, you may end up having an air pocket inside the engine block or cylinder head. 

The cylinder head has multiple coolant opacities inside. The coolant may trap in the blocks of the cylinder head. It will prevent the coolant from flowing freely between the radiator and the engine.

Consequently, it will overheat the engine. This situation sometimes can cause bubbling and allow the coolant to shoot out of the radiator


Purging the air out of the cooling system is the solution to solve the air pocket issue. The following tutorial will help you in bleeding the air out of the coolant system: 

We highly recommend you purge the air out of the coolant system every time you flush the coolant and add fresh antifreeze. 

02. Bad Radiator Cap

A failed radiator cap can also be a culprit that causes the coolant to leak out of the radiator. If the radiator cap is at fault or its seal gets damaged, the radiator can’t hold enough pressure. As a result, the coolant comes out of the radiator. 


You must replace the radiator cap if it’s at fault or its rubber seal gets damaged. Just get a new radiator cap.

Then, remove the old one by keeping the hand on the radiator and twisting your hand to the left. Keep twisting until it comes loose. Once you remove the old radiator cap, install a new one. 

03. Cylinder Head Gets Cracked Or Warped

A cracked cylinder head is also responsible for the coolant to leak out of the radiator. Excessive heat causes the cylinder head to go bad.

Too much heat expands the metal parts of the cylinder head and leads it to a crack. Poor engine performance, coolant leaks, oil leaks, and smoke out of the engine are some signs of a cracked cylinder head. 


It requires mechanical skills to replace the cylinder head if it gets cracked or damaged. So, We highly suggest you call a certified mechanic to do this task for you. On the other hand, you can watch this tutorial if you are mechanically inclined: 

04. Blown-out Head Gasket

Yes, a leaky or burn-out head gasket can also cause the coolant to come out of the radiator. If the head gasket is at fault, it will produce excessive heat from the cylinder, which heats the coolant as well.

As a result, there will be extra pressure in the coolant system. And this pressure will expand hoses and force the coolant to leak out of weak areas like the worn-out radiator. 


If the head gasket is leaking, you have two options to fix this issue. You can either replace the head gasket or use a sealer to fix this issue. Replacing the head gasket will cost a fortune ($1000).

So, you can choose the cheap yet effective route to seal the head gasket. And this video will help you how to use a sealant to seal the head gasket correctly: 

05. A Bad Thermostat

It’s a rare case that a bad thermostat can leak coolant out of the radiator. But, sometimes an exceptional thing may occur like the coolant leaking from the radiator. If the thermostat is stuck closed, it will bring more damage than a leak.

In this case, we recommend you take a look at the percentage of antifreeze and water. Ensure their levels in the radiator and the overflow tank are in the right place. The operating temperature of the radiator and the overflow are different. The thermostat opens and closes based on the temperature of the coolant mixture.

If it’s too hot, it will open to circulate and cool down the motor. When the thermostat remains stuck closed, it will make the coolant too hot and the coolant will try to find a way out. And unfortunately, the antifreeze finds the radiator on its way to leaking out. 


As we mentioned earlier, it’s uncommon for coolant to shoot out of the radiator because of a faulty thermostat. If you can’t determine the exact leaking point of the coolant, we recommend you call a technician to have a coolant system pressure test to detect the coolant leaking source. 


What causes too much pressure in the cooling system?

If the radiator cap gets damaged, the coolant will leak into your hot engine. As a result, it causes a lot of pressure on the cooling system. In the worst case, the coolant may shoot out of the radiator cap. 

What are the signs of a blown head gasket?

White smoke out of the tailpipe, coolant loss, and engine overheating are some symptoms of a blown head gasket. 

What are the symptoms of a failing thermostat?

High temperature, overheated engine, unusual noise coming out of the engine, and coolant leak are some signs of a failing thermostat. 


Dealing with the coolant shooting out of radiator issues is a must. If you don’t fix the problem immediately, it will overheat the engine and bring permanent damage to the engine. And you know replacing an engine requires a lot of money. 

Fortunately, we broke down every reason that causes the coolant to shoot out of the radiator. So, follow our guide and take the necessary initiatives to solve this problem. Best of Luck!

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

Leave a Comment