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Can Flex Seal Be Used on Cars? (Explained)

Flex seal is considered as an effective and easy to use sealant by experts. Flex seal is popular for having the ability to be used on many different types of surfaces. But their effectiveness and adhesiveness do not work equally on all surfaces. 

Today, we are going to discuss and find out whether flex seals can be used on cars or not. 

Can Flex Seal Be Used On Cars?

Flex seals can be used on various parts of the car. Flex seal mainly possesses the ability to be used on cars for minor repairs like side view mirrors, car windows, undercarriage of the car, exterior trims, and wheel wells. It can also be used to protect the car from rust and corrosion.

Walk through this section to learn more about flex seals and if you can use them on following car parts –

Car engine:

Car engine is one of the most important parts of a car. It has many minor and major parts and your car can not function without a healthy engine. However, several parts of the car engine can develop cracks and holes over time. 

These cracks and holes can be repaired with the products of Flex Seal. 

But the important thing to remember here is that flex seals work as a temporary repairing measure and not a permanent one when it comes to car engines. 

Car exhaust:

The exhaust system is a crucial part of the car. The primary job of car exhaust is to filter the dangerous exhaust gasses and make your car eco friendly. But the exhaust system of a car becomes affected with several holes and cracks and will require immediate attention. 

Flex Seal products can be used to repair these holes and cracks. However, flex seal products do not last for a long time inside the exhaust system as it is constantly exposed to high temperature conditions. 

Car radiators:

Manufacturers have not made flex seal products with the purpose of making it usable on car radiators. Car radiators can require repairing from time to time. 

But that can not be done with flex seal products as they do not possess the required ability to be used on such a complex surface like a car radiator.

Car coolant tank:

The coolant tank of a car can need repairing because of holes and cracks on them. But flex seal products can not be used in this case. Flex seal products do not have the ability to be effective on the coolant tank of a car. You can use it as a temporary solution. 

But your coolant tank will need professional attention soon. 

Car mufflers:

Car mufflers go through an excessive pressure situation everyday and can require repairing from time to time. However, flex seal products are not considered as the best method when it comes to repairing your car muffler. 

You can use a flex seal on your car muffler as a temporary solution but not a permanent one. 

Car tires:

The tires of your car can start giving you problems due to cracks and holes. Flex seal products can be used as a temporary solution to repair faulty tires. But you will need to get your car tires repaired by a mechanic as soon as possible.

Can You Use Flex Seal on car rust?

There are many uses of flex seals on cars. Flex seal can be used on car rust because of its effectiveness. Some experts suggest that you coat your car with Flex seal spray to keep your car free from rust. 

The components of flex seal are capable of keeping out excessive water, moisture, and air from the important parts of your car.

Some car owners even spray flex seals on the undercarriage of their car to keep away rust. However, applying flex seal spray directly on the rusty areas does not remove rust. Flex seal is only able to decrease the spread of rust and can not remove it completely.

Will flex seal fix my car’s oil leak?

Flex seal does not possess the ability to stop your car’s oil leak. Flex seals can be used to slow down the oil but it can not stop it completely. Flex seal is not made with the purpose to be used on something as complex as oil leak. 

If your car engine has started leaking oil and you can not take it to a mechanic immediately, then you can certainly apply a flex seal on the leakage area to slow down the leak. But the oil leak has to be repaired immediately by a mechanic.

5 reasons why you can flex seal a car

There are a lot of valid reasons why you can use flex seals on your car. Let’s discuss them in detail. 


Flex seal has been labeled as a proven sealant by many experts. The effectiveness of flex seal products make it applicable on a complex surface like a car. 

Car is made of many different surfaces and you can use flex seals on these different surfaces of the car because of its effectiveness.


Another trait of flex seal products is their durability. They can last for a long time on different surfaces and under different conditions. That is why flex seal products can be used on different parts of the car barring excessive high temperature conditions. 

Under excessive high temperature conditions, flex seal products are not so durable and can wear off easily. 

Temporary solution:

Flex seal products can be used as temporary solutions for different repairing procedures of the car. If a crucial part of your car becomes damaged, you can use a flex seal to stop the damage temporarily until you get it checked by a mechanic. 

But flex seal products can also be used as a permanent solution when it comes to minor repairs. 

Easy to use:

Flex seal products are very easy to use and they come readymade. You do not have to add or subtract anything from it. Flex seal glue, flex seal spray and flex seal tape are the most compatible products for a complex surface like a car. 


Flex seal products do not cost very much. If you want to do some minor repairs on your car or stop further damages, you can certainly buy and use a flex seal product without worrying too much about the size of your wallet.

What does flex seal help with the car?

Many people do not know about the applications of flex seals on the car. Let’s discuss in detail to find what flex seal helps with the car.

Helps with the headlights:

The headlights are protected by a casting that needs constant repairing due to cracks. Flex seal tape comes in handy while repairing the headlight castings. 

Helps with the exterior trim:

The exterior trims of your car can start falling off due to changing weather conditions. Flex seal glue can be used on the exterior trims of the car to stop them from falling off.

Helps with the door jambs:

Faulty door jambs are responsible for letting water get into your car. The door jambs of your car can be fixed with the help of a flex seal.

Helps with the mirrors:

The side view mirrors of your car can get broken due to minor accidents. Flex seal can be used as a temporary solution in this case.

Helps with the car windows:

You can use flex seals on the inside and outside part of your car windows to get rid of any leaks. 

Helps with the rust:

Flex seal can be applied on the undercarriage of the car to protect it from rust.

How do you Flex Seal a car?

Flex sealing a car might seem like a daunting task if you do not have prior experience regarding the matter. Let’s discuss in detail about how you can Flex Seal a car.

Identify the problem:

First of all, you will need to identify which part of your car needs to be flex sealed. The most common problems flex seals can help with are car window, side view mirror, undercarriage, door jambs, exterior trim, wheel wells, and headlight castings. 

Clean the part:

You will need to clean the part of the car you are going to use the flex seal on. Using flex seals on a dirty area will cut down its effectiveness. You can either use fresh water to clean the car’s part or take the help of a car cleaning liquid. 

Apply the flex seal:

You can choose from a variety of flex seal products to use on your car. Flex seal glue, flex seal spray, and flex seal tape are usually used to flex seal a car. The use of the flex seal will vary according to the part of the car.

Final Thoughts

Flex seal can be applied on the car for minor repairs and works as a temporary solution for major repairs. Flex seal products can not be used on complex surfaces like car radiators, car mufflers, and car exhaust. But it can be used on side view mirrors, car windows, and wheel wells.