What Causes Freeze Plugs to Blow Out: 7 Easy Solutions!

Freeze plugs are an important part of vehicles. It protects the engine of a vehicle from damage. But many people are suffering from problems related to it.

It’s a common problem but what causes freeze plugs to blow out?

Overheating, high pressure, aged freeze plug, leakage, and coolant amount are the main ones. To fix these issues temperature and pressure should always be maintained. The freeze plug should be replaced from time to time. You should always keep an eye on the coolant level as well as the radiator cap.

That’s not all! We have discussed some other common reasons for this issue. Also, we have given some solutions which can help you with this issue. 

Stay with us to find the solutions. You will not be disappointed!

What Causes Freeze Plugs to Blow Out

Many reasons behind this problem. People often ask what would cause a freeze plug to blow out? We have found some probable reasons and solutions to it. Also, the freeze plugs might go bad. That also has some bad consequences.

What happens when freeze plugs go bad? Freeze plugs usually leak coolant when they go bad. However, they do not go bad completely so the leakage is very slow. 

We have given 7 problems with solutions here. So go on and identify the one you’re facing and solve as mentioned!

Problem 1: Low Coolant Level

It is the most important point to take care of. If there is a low level of coolant, then the engine loses its efficiency. The engine will create a lot of fumes and smoke. It can pressurize the plug.

A low coolant level heats the engine easily. The overheated engine can create more pressure. It can also damage the engine as well.


You should keep your coolant level between high to medium.

The coolant reservoir is mainly transparent. Also here is a bottom line and a top labeled line present. 

If the coolant is under the below line, it means the level is low. You can refill it if it is low.

We have some recommendations on the coolant below.

Engine Ice TYDS008 High-Performance CoolantCheck Latest Price
Zerex Asian Vehicle Red Silicate and Borate Free CoolantCheck Latest Price
Zerex Original Green Low Silicate Ready-to-Use Antifreeze/CoolantCheck Latest Price

Problem 2: Overheating

Overheating is a bad sign. It means there is a problem with your engine. It can occur for the presence of leakage, or problem in the coolant. 

Also, there will appear leakage if it is overheating. Overheating increases the pressure. And the high pressure gives force to the freeze plug and it blows out.

Source: engineeringchoice.com


You should find out the main problem. You should check all the leakages. If there is any leakage, it should be repaired. Also, you should change the thermostat after a decent time. 

You can go on a test drive. If you are unable to find any problem, it is better to go to the mechanic.

Besides, you should take regular care of your vehicle. Washing and cleaning your vehicle can solve half of this problem. You can remove the antenna during washing your vehicle.

Problem 3: High Pressure

The thermostat is an important element. It has a significant role in the cooling system. If there is a sticking thermostat, then it can not cool down the temperature easily. As the temperature rises, it will create high pressure.

But how can you tell if your thermostat is stuck?

If it isn’t flowing, give your engine some time to warm up. After 10 to 20 minutes, the coolant should reach the proper temperature and start to flow. Your thermostat may be jammed closed if it doesn’t start to flow yet.

Until you replace the thermostat there will always be a high pressure inside the engine. It can cause the freeze plug to blow out.

So a commonly asked question is why would freeze plugs pop out. If you find a sticking thermostat then the answer is known to you.


You need to keep the temperature under the hood cool. If you notice any aforementioned symptoms that indicate that your thermostat is stuck just open the hood.

By doing this, you can prevent harm to other parts. If there is actually a sticking thermostat, you should replace it.

If you’re not sure how to replace the thermostat then check out this video guide and change it accordingly.

A new thermostat will resist high pressure. And that will help you to get rid of the problem.

Problem 4: Freeze Plug is Not Replaced for a Long Time

Every product has a lifetime. Your freeze plug can be good for up to 100,000 miles. People often don’t check the freeze plug. If it runs more than its limit, it’ll go bad. An old and expired freeze plug can create this type of problem.

Freeze Plug
Source: moparforums.com


You should check all the parts, especially the freeze plug. The freeze plug should be replaced after the car runs 100,000 miles. 

A bad freeze plug can hamper the engine. It can affect the cooling system. The freeze plug will frequently blow out. 

Also, it will raise the pressure. That will result in high temperatures.

A bad freeze plug can damage the engine. Then you have to pay a lot for the engine. So you should check the freeze plugs with a flashlight. In this way, you can easily find out the age one. 

You should drain the antifreeze and remove the blocking part. Then remove the plug and clean the hole. After that, fix a new one.

After every three years, it should be replaced. Or after 60,000 miles you can replace it.

Problem 5: Freeze Plug Leak

What happens when a freeze plug pops out? 

It occurs because there must be a leak present. Coolant will leak from the bad freeze plug. Your engine cooling system will not work as before. The leak will not let your engine cool down quickly.

Freeze Plug Leak
Source: dodgeforum.com

If there is any leakage in the plug, the coolant will change its odor. It will turn from a sweet odor to a distinct odor. Gas exhaustion is also caused by this.

Or you can see something like this beneath your car.


You should replace the plug with a new one. We have already given the process of how you can replace it. You can check that.

Or you can try to reseal a leaking freeze plug with sealants. I normally use K-Seal ST5501 Multi Purpose sealant to do all my sealing job. Also, I’ve read rave reviews of Bar’s Leaks 1186 Liquid Aluminum Stop Leak as well.

You can use any of them or any other sealant to repair the leaks. If you’re not quite sure how to do that then check this video on how to use the Bar’s Leaks Seal liquid to stop leaks.

Problem 6: Improper Adjustment of the Freeze Plug

You should always keep in mind that the freeze plug must be the correct size. There will be no adjustment problem if it is accurate in size. There can be some gaps or leaks, or even the valve can be oversized.


You should check all the freeze plugs. Plugging the brake line can be done. You should clean the adjustment areas. You should replace the valve after a certain time. While replacing the valve, you should be more careful.

Problem 7:  Issue With Radiator Cap

The radiator cap can be bad. A bad radiator cap can heat the engine. The coolant reservoir tank might overflow sometimes. You can find some coolant leaking from the bad radiator cap. These causes are already mentioned in the above points.


A radiator helps to release the pressure. Different vehicles prefer individual pressure. You can easily fix it on your own. 

But you should be careful before you replace a radiator cap. The engine must be cool. Or there will cause a severe burn or injury to your hand.

All the seven problems are related to each other. If any of them occur, it will create the same situation. The mechanism of all the problems is connected.

The consequences of these problems are the same. So you have to find out the specific one. You can follow the solutions. If you are not an expert at it, take it to an expert.

Frequently Asked Questions (FAQs)

Can you drive with a leaking freeze plug?

You can drive, but we do not recommend you to do so. There will be a leak of coolant from the freeze plug. So there will appear a bad smell of coolant. If your engine is full of coolant, you can drive. But it will no longer fill up. The engine will lose it quickly.

Do you have to drain the coolant to replace the freeze plug?

Yes, you should drain the coolant to replace the freeze plug. You should open the drain valve. Drain all the coolant. Then you can replace the freeze plug. After that, you should use a cloth to clean the block hole.

Can you reuse a freeze plug?

You can not reuse a freeze plug. Reusing a freeze plug is a bad decision. The standard time to use it is for three years. After that, the sides of the freeze plug will reduce their thickness. If you reuse it, you can notice that it will not fix properly. It will not be as tight as before.


We have tried to give the solution of what causes freeze plugs to blow out. 

These are basic problems that people often face. You can check these problems according to our article. Also, go for the solution.

Hope you will get benefits from our solutions! Stay safe and enjoy your driving.

Robert Lozano

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