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Radiator Stop Leak Review

You don't want to neglect a cooling system leak. The first time I had one, the majority of my coolant disappeared in a day.

What Is Radiator Stop Leak?

I recently wrote an article about engine oil stop leak and its benefits, and I wanted to follow up with an article on radiator stop leak. Even though the two products have similar names, they are not the same at all.

Stop leak: Stop leak varies greatly depending on what system you're using it for. Inside the engine, stop leak is designed to treat the rubber seals that keep oil from entering into the fuel mixture for combustion. Stop leak for engine oil is designed to soften and expand the rubber and keep the rubber seals fresh and working.

Radiator stop leak: Radiator stop leak is different. This product is designed to seal a leak that's happening somewhere in the cooling system, and if not used properly, side effects might ensue.

Radiator stop leak is a goopy substance that can cause quite a lot of trouble down the road if you're not careful. So before you go out and buy radiator stop leak, open up the hood of your car and see if you can't specifically locate where your leak is coming from. Many times, the leak will occur on a part of the cooling system that's easy to repair without the use of goopy additives like radiator stop leak. Below, I'll diagram what the cooling system looks like and how to try to diagnose where your leak is coming from.

When to Use Radiator Stop Leak

In the following section, we'll go through how to diagnose and find where your leak is. But sometimes, especially in certain older vehicles, there isn't just one leak. Sometimes the whole system needs to be treated. There are certain old Fords and other manufacturers that had numerous problems with the cooling system as a whole. In this scenario, radiator stop leak might be an excellent way to go, because it will treat the whole cooling system all at once. Just make sure you get the very best radiator stop leak out there. If you get a poor stop leak, it can clog up your pipes with goopy stop leak and cause unwanted pressure variances and larger problems. I've left you a link at the bottom to a product that has a lot of positive testimonials. Hopefully that will cut down on any side effects that sometimes pop up from poor quality radiator stop leak.

If, however, your vehicle isn't an old beater and you think that your coolant leak might be fairly well localized to one spot, go through the next section and see if you can't identify the specific area where your radiator leak is. You don't want to neglect a cooling system leak. The first time I had one, the majority of my coolant disappeared in a day and I burned through a few quarts of oil because my engine got so hot. I had to replace not only my radiator but get an immediate oil change, as well.

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This is a picture of an aluminum heat sink.  It's not a radiator, but is similar.  Depending on the severity of your leak, radiator stop leak will fix most mild leaks inside your radiator.

This is a picture of an aluminum heat sink. It's not a radiator, but is similar. Depending on the severity of your leak, radiator stop leak will fix most mild leaks inside your radiator.

Finding Your Leak

There are three main components to the cooling system of your car. The first is the radiator itself.

1. Radiator: This component is basically just a large aluminum heat sink, like the ones you might see on top of the processor inside your computer. The water flows from the hot engine through the radiator, with air rushing over the surface from the fan and from the outside air, getting cooled. Then the water flows back into the engine to reabsorb heat. The two tubes that carry the water back and forth from the engine are called the upper radiator hose and the lower radiator hose. Those are the second components of your cooling system.

2. Upper and Lower Radiator Hoses: The upper radiator hose carries the hot water from the engine into the top of the radiator to be filtered through the radiator and cooled. The processed water then flows through the lower radiator hose back into the engine to reabsorb heat. These two tubes, because they're made of rubber and undergo constant changes in heat, can wear out easily, or else become loose and begin to leak. The first thing you ought to check is whether or not your upper and lower radiator hoses are attached firmly and whether or not they're leaking. If you warm up your engine and open up the hood, leaving your car running, you should be able to tell whether the leak is coming from one of these two hoses, or whether it's coming from the radiator itself. If the leak is coming from one of the two hoses, you're in luck because they're pretty easy to change.

The is the icon for windshield wiper fluid. Don't pour radiator stop leak in here or you might have a big problem.

The is the icon for windshield wiper fluid. Don't pour radiator stop leak in here or you might have a big problem.

3. Coolant Overflow Tank: The third component of your cooling system is the coolant overflow tank. This is generally a clear plastic tank that's off to one side of the radiator. Most cars have two plastic tanks that each hold about a half a gallon of liquid. One is the coolant overflow tank and the other is the windshield wiper fluid tank. You'll have to identify which one is which. The windshield wiper fluid tank generally has the icon pictured to the right stamped somewhere on it or on the cap. If you really do have a leak in your coolant system, then odds are that your coolant overflow tank is completely empty. When the car is cold, the coolant overflow tank is at it's fullest. As you drive and more coolant is flowing through the system to keep the engine at a safe temperature, the coolant overflow tank adds more liquid to the cooling system. There's a chance that your leak is coming from the coolant overflow tank, but this is pretty rare. If the tank gets cracked and begins to leak, you'll be able to see droplets of coolant falling from it. If that's the case, then you're in luck again, because the coolant overflow tank is pretty easy to change out.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

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