Can Radiator Stop Leak Cause Overheating? (Explained)

Replacing a car radiator can be an expensive and time-consuming task, that is why radiator stop leaks became so popular. While it does help, it is not a permanent solution to fixing a leaking radiator but since “radiator stop leaks” are temporary fixes do they have any negative effects on your engine? can radiator stop leaks additive cause overheating? let’s find out!

What is a Radiator stop leak?

Radiator Stop leak is a synthetic additive that can be used to repair radiator leaks in automobiles. it helps the radiator stop leaks by sealing the air gap between two components with low molecular weight or silicone rubber material.

Most manufacturers of radiator stop leak recommend that it be used with care as it could cause damage to your engine in the long term, through corrosion. there are also several claims that radiator stop leak can cause system failure and cause other damage. since it has a tendency to dry up, it can leave a residue which due to buildup of the deposited sealant or flammable vapors, resulting in engine fires.

However, that rarely happens, as long as you use it as a temporary fix to your leak.

According to the manufacturers of the additive, you should only use it once you already have a leak in one of your car’s radiator. Therefore, if a leak occurs when you are driving on a highway, then it is not the time to start rushing to buy an unnecessary additive just so that you can at least make your drive home and drive around for another 10 000 miles before replacing the radiator completely.

Can radiator stop leak additive cause overheating?

In general, a stop leak can not cause overheating. but if you use it for longer than recommended, then it could cause issues with the cooling system. when you use a radiator to stop leaks, in most cases, it tends to dry and leave deposits inside the cooling system. intake gaskets are especially prone to this issue and may need to be replaced at a later time.

How long does the stop leak last in a radiator?

How long the product is useful varies depending on the type and severity of the leak.

If you have a leak in your radiator that is mild to moderate, it is likely that you can drive around with a stop leak on your car and see no harm done to your engine; however, if the leak gets worse or falls into severe categories, then there may be corrosion issues with your engine.

Usually, stop leaks additives can be good for 10000 miles, but if they are used early and as a temporary solution to a leaking radiator, then they can last up to 30000 miles.

Will using a Stop Leak ruin my radiator?

In general, the product works well. However, depending on the leak and how much damage has already been done to your radiator system, it is possible that stopping the leak will be good for your radiator and will not ruin it since it’s already damaged and does need replacing.

How long does it take for Stop leak to work?

Usually, a radiator stop leak can stop a leak instantly, in some cases it takes up to 30 minutes. but if the leak didn’t stop in 30 minutes, then you can try another product and try again.

If your radiator is leaking badly, meaning that the cooling system is not holding any pressure and requires an immediate repair, then this fix is not going to be permanent as you will need to replace the radiator soon so get ready for a new one.


If you are looking for a quick fix to your leaking radiator, then radiator stop leaks can be a temporary solution. it can help you get from point A to point B but do not rely on it too much and hope that it works for another 30 000 miles. Be cautious when using this additive and follow the manufacturer’s instructions to the dot and always choose a reputable brand then you won’t have to worry about the additive causing overheating.