Radiator stop leaks are a touchy subject in the automotive world, but there are products out there which can be an effective stop-gap measure to keep your car up and running. If you’re looking to avoid lemons, or even just determine if a stop leak is the right product for you to spend some money on then you’re in the right place.
We’ve dug up four effective products and the information you need to make an informed choice.
Best Overall !
K-Seal is probably the most solid option to go with in order to get a long lasting fix on a serious radiator problem. Remember that even the best is temporary, but this is your best shot if you’ve got a serious problem.
Top 5 Radiator Stop Leaks
|Genuine GM Fluid||All|
|Bar's Leaks 1186||Aluminum|
|Bar's Leaks 1109||Copper|
When to Use a Radiator Stop Leak
Before you consider using one of these products, keep the following in mind: chemical solutions to radiator problems are not intended to be a permanent fix, no matter what the bottle says.
In general, you’ll find these products useful primarily for tiny “pin hole” leaks, rather than wanting to use them on anything which can actually be seen with the naked eye. You also want to use the least aggressive product possible for the best results, since stop leak products can cause problems in and of themselves.
- Top 5 Radiator Stop Leaks
- When to Use a Radiator Stop Leak
It can be hard to tell just how aggressive a product is from the marketing around it, since almost all of them are billed as a permanent solution to the problem, which isn’t really true.
Basically, the more coolant you’re losing over time, the more aggressive of a product you’ll want to use. If you get something too gooey, however, the product can also cause clogging in the radiator which will render everything ineffective and you’ll have to replace the part anyways.
If you’re using a stop leak product, it should only be as a gap until you have the time and money to invest in a new radiator.
How Does a Radiator Stop Leak Work
Rather than mystifying the products, like the manufacturers tend to do, let’s discuss exactly what makes these products work.
Radiator stop leaks work by adding a fiber or other mass to the coolant system. Naturally, these larger particles will tend to be attracted to the lower pressure areas, namely where the leaks are, and clog together to form a gap.
Some products will use a low melting point metal additive as well, forming a temporary weld when the radiator cools down after usage. These can be great for some applications, but it can be hard to tell which is which when you’re just looking at the bottle. Basically: the companies are loathe to say exactly what their product does since it runs the risk of their formula being stolen.
If this sounds kind of dangerous… it can be. Never use more than recommended. You run the risk of fouling your entire coolant system and causing damage to more than just your radiator.
How to Use a Radiator Stop Leak Effectively
Make sure you follow all of the instructions on the bottle in addition to the following general outline in order to make sure you run the best chance of fixing things. Some products will need to be shaken and pellets and powders will have specific directions for how much to add. Follow the amounts to the letter. Too much is definitely not a good thing.
First, you’ll need to let the car cool down and remove the radiator cap. Don’t try to remove it when the car is still hot for obvious reasons, a face full of steam definitely isn’t a good time. Even if it’s cool be careful, slowly crack the pressure rather than just ripping it open. Pressure differentials can do some weird stuff.
Afterwards, you’ll want to add the product that you’ve chosen and allow the engine to warm up to normal running temperature. Keep an eye on the ground under the vehicle to figure out when the leak stops. Once everything stops, let the engine run for a few more minutes and then you can turn the key.
Even if the product doesn’t mention it, we recommend flushing the system while it’s still hot. The last thing you need is excessive amounts of fibers or low melting point metals running around in your radiator. The build-up can cause serious problems throughout the system, and while it’s not guaranteed you’re already looking at the expense of replacing a radiator so it’s probably best to err on the side of caution.
If you’re particularly paranoid, you can flush the whole system twice with water before adding the manufacturer recommended antifreeze back into the system.
From now until your radiator is replaced or repaired you’ll want to keep an eye on the temperature and fluid level. Get things replaced as soon as you can, you might be looking at anywhere from a couple hundred to more than a thousand miles before you have to actually take care of things but remember that a radiator stop leak is not a permanent fix.
How to Pick a Radiator Stop Leak
While there’s a common perception of stop leaks being automotive snake oil, the fact is that some will work in order to let you avoid minor repairs for anywhere from a short time to an extended period.
We’ve done the work of digging through the reviews of this extensive part of the market in order to bring you the best and try to ascertain the situations they work best in. The main thing you’ll want to do is check to make sure the product is compatible with your radiator material.
Those products which are compatible with only one type of radiator may be the best to go with, but it can be hard to tell. This limited capability usually indicates a more precise chemical reaction however.
For the most part, pellets and powders will be a cheaper option. They’ll also work just as well as most fluids, since the solvent matters less once they’re dissolved.
Fluids on the other hand are a bit more foolproof as most are made to fit a specific size of cooling system.
Whatever you choose to go with, you should be able to get back on the road pretty quickly but get that radiator fixed properly as soon as you can. You wouldn’t just tape gauze over a cut that needed stitches, but it might let you get to the doctor without losing too much blood. Pretty much the same principles apply here.