What Happens When a Radiator Hose Blows?

A radiator hose is a link between the radiator and the engine. It is divided into two, which are the upper and lower hose. Hot coolants from the engine pass through the upper hose, and the lower hose carries cool coolants.

A vehicle’s upper radiator hose blowing off is a common thing because the hose has to handle hot liquid constantly.

In addition, the lower radiator hose is also prone to collapse due to problems from the radiators, like blockages.

This article will examine what happens when a radiator hose blows,the causes, how to recognize a blown radiator, and the temporary fix.

blown radiator hose

What Happens When A Radiator Hose Blows?

The radiator hose is an essential part of the radiator that carries coolants from the radiator to the engine. When the radiator hose blows up, the coolant supply is cut off from the radiator to the engine. If the problem is not properly checked, it could result in parts of the engine getting damaged and could eventually lead to a failed engine.

Furthermore, the first noticeable symptom of a blown hose is leakage. You will notice a coolant leak on the ground. It stops the engine from receiving coolants resulting in heat build-up.

Causes of Blown Radiator Hose

Several factors could cause a blown radiator hose, ranging from the hose’s age to other common causes. When you understand what causes radiator hose to pop off or blow, you will better understand how to fix the problem.

Below are some of the causes of a radiator hose burst.

1. Damaged cap

One of the most common causes of a blownhose can be traced to the radiator cap. A damaged cap will cause pressure to build up in the system; when the pressure reaches a certain level, it causes a collapse or burst radiator hose.

Some of the causes of a damaged or faulty radiator cap could be age or rust. You should periodically check the cap to see if it is in good condition. In some cases, the cap could be fine; the cause of the blown hose could be due to inappropriately closing the cap.

2. Age of the Hose

When your radiator hose blows off, it could be due to how long you have used it. Like most parts of the vehicle, the hose has a limited use time, although it can last forever.

The radiator hose is responsible for moving coolants to and from the engine. The problem here is that the coolant varies in temperature. It is usually very hot when coming from the engine with extremely high pressure. It could damage the hose over time, causing it to get weaker and more vulnerable to leaks, bursts or other damages.

3. Clogged radiator

Another issue that could cause a radiator hose burst while driving is a clogged radiator. The radiator hose is directly connected to the radiator, making it vulnerable to problems that affect it.

When the radiator is clogged, it will affect the radiator hose. It will cause the lower part of the hose to collapse.  It will also generate air in radiator.

4. Blocked tank hose

When the tank hose is blocked, it limits or completely stops air from flowing through the expansion tank. It creates a similar effect as having a damaged radiator cap. The issue creates a vacuum and leads to a collapse of the hose.

How Do You Know If I Have A Blown Radiator Hose?

There are two major ways you could know if you have a blown radiator hose. You could observe for blown or leaking radiator hose symptoms or test the hose using simple steps.

Firstly, we will be looking at some blown radiator hose symptoms. They include the following.

1. Engine overheating

When you notice that your engine gets overheated too frequently, it could mean that it does not get enough coolant from the radiator. It could result from a leak caused by a blown radiator hose.

When the hose is damaged in any way and cannot carry coolants to the engine, the engine will build up enormous heat, which could damage its parts. Overheating can damage the cylinder walls, or the pistons deform, bend or warp.

2. Leaking coolants

One obvious symptom of a blown radiator hose is leaking coolants. The hose is a medium where coolants flow from the radiator to the engine. Once the hose is blown, it creates an opening for the coolants to escape. You can see the coolant visibly on the floor beneath the vehicle.

3. Visibly damaged hose

Once the hose is blown out, you can find the damaged part on the hose by examining it. You will notice a blown-out or collapsed hose by looking under the hood.

4. Low coolants

Due to the leak caused by the opening in the blown hose, all the coolants in the reservoir and radiator will continuously leak. It will continue until no coolants are left in for the engine to use.

Once you notice that the low coolant light is on and you have to refill the coolants too frequently, then there is a leak somewhere. You could find out by looking beneath the vehicle after refilling them with coolants for visible coolants on the floor.

Another way to know if your radiator hose is damaged is by testing or examining the radiator. You could first squeeze the upper radiator hose. The hose is old and bad if it is hard or has a crunchy feeling.

Also, you could examine the hose for any apparent damages, like a busted, collapsed or leaking sign.

How to Temporarily Fix Bad Radiator Hose

Driving the vehicle in such conditions could be dangerous with a damaged radiator hose. The good news is there is a temporary fix for the hose, which can afford you more miles. It will give you the time to get out of the difficult situation and get to a mechanic for a hose replacement.

Furthermore, to get the temporary fix started, all you need is an insulating tape which you can find in any local store nearby. Once you have the tape, wrap it around the affected part of the hose. You can use duct tape if you do not have insulating tape.

You mustn’t drive your vehicle for too long with this temporary fix. The tape might not be able to handle the heat from the coolants, and another leak could be created in no time.

The best solution for this problem is to replace the hose immediately. If repair is delayed, it could cause severe damage to the radiator and engine. It would cost even more to have it fixed.


A radiator hose plays a vital role in properly working the engine. It is why when the radiatorhose blew off while drivingand you opt for a temporary fix, you need not settle for that. It would be best to replace the damaged hose immediately to avoid further damage.   

Our expert mechanic has shared his knowledge regarding what happens when a radiator hose blows? Read it to learn the temporary fixing process.

Akindayini Temiloluwa

I am Akindayini Temiloluwa, an automotive expert writer and car enthusiast. I have over three years of experience in the automotive writing niche and have completed over 300 pieces of content from 50 projects. I have vast knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance. My goal as an automotive content writer is to simplify the most challenging concepts for my readers, help them self-diagnose what may be wrong with their vehicles and offer real value for their time.

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