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Here's Why You Should Think Twice Before Using Tire Sealant

It may seem like the perfect product for fixing a flat tire, but sealant has plenty of drawbacks. We weigh the pros and cons of this spare-tire alternative.
fixing flat with tire sealant

Different types of flat tires call for different ways to fix them, depending on the situation you're in, the severity of the damage, and the price. If you get a small puncture and not a full blowout, a can of aerosol tire sealant can come in handy — just attach the hose on the product to your tire's valve stem, empty the can's contents into the tire, and keep on driving.

Keeping sealant on hand may offer a quick fix to get your car up and running again. But using it can have drawbacks if you're concerned about tire and road safety. Many automotive brands produce their own tire sealants, so before plunking down some cash for a can, weigh the tire sealant pros and cons.

The Tire Sealant Pros

It's a fast, convenient, and affordable DIY solution.
Many tire sealants — think products like Fix-A-Flat or Slime — come in a pressurized can and are easy to apply. When you spray the product into the valve, the tire inflates and the formula coats the inside of the tire, plugging leaks or punctures. Within a few minutes, you can start driving your car so the gel spreads evenly.

Even with more major flats, a good sealant will fill up your tires enough to drive the car a short distance, like to the side of the road. That way, you can get out of the way of dangerous traffic and reduce the risk of harm to you, your passengers, or your wheels. It's a safe option if you don't have a spare tire. Sealant is readily sold in automotive and retail stores, and it's cheap and long-lasting.

Tire sealant may prevent flat tires.
Sealants are most associated with fixing tire punctures, but using them for preventing flat tires is often overlooked, according to Marc Lapointe, general manager of Seaway Hyundai in Ontario, Canada.

"Preventative tire sealants are particularly helpful if you live in a more rural area where there is a lot of gravel or rocks, or if you tend to be around job sites, where nails and screws routinely find their way onto the road and driveways," he says. "Using a preventative tire sealant is an easy and affordable way to give the tire an extra layer of protection and help prevent potential punctures that would cost you more money down the road."

SEE ALSO: Tools You Should Always Have in Your Car in Case of Emergency

Sealant may prolong the life of old tires.
Tire sealant doesn't need to be applied only in the event of a flat tire. Jim Wang of Wallet Hacks says that he uses sealant to fill in age- and wear-related cracks in the tires of his farm equipment — a lawn mower, tractor, and wheelbarrow — to keep the items running longer. "The tires themselves are relatively old, have to withstand some rough conditions and so they develop little cracks," Wang says. "A jug of sealant is less than $50, and if it can get a few more years of life out of $500 tires, it's worth it by a long shot."

The Tire Sealant Cons

Tire sealant may damage — rather than fix — your tires.
It may be simple to use, but when applied incorrectly, tire sealant may further ruin your tire. Sealant is designed to disperse and fill up puncture holes while aided by the heat of the tire. If it doesn't warm up fast enough, it can pool toward the bottom of the tire and lead to potential wheel misalignment. Tire sealant may also damage the sensors inside your tire, keeping the pressure constant and failing to alert the driver inside the car if the tire pressure was to actually become low.

It's not a permanent fix for a flat tire.
Leaky tire sealant has been known to corrode wheels, which can be costly to replace. Plus, no tire sealant is a permanent solution. In fact, you may need to buy a new tire to replace your flat because many service centers won't repair a tire treated with a chemical sealant.

You may need to buy a new tire to replace your flat because many service centers won't repair a tire treated with a chemical sealant.

Sealants may contain hazardous chemicals, and removing sealant may be time-consuming for a repair person. Using a canned sealant can increase the pressure inside the tire, too, risking a blowout or injury to the person who's repairing the tire. Sealants may also void your tire's warranty, so that replacement tire will end up costing full price.

When Should You Use Tire Sealant?

Think of tire sealant as an alternative to the spare tire. Only use it in emergency situations, and drive on a sealed tire just to take it to get repaired or replaced. According to CarsDirect, take the precautions when applying sealant that you would when changing a tire, such as ensuring that your car is safely on the curb or shoulder of the road. Depending on the size of your car, SUV, or truck, keep a larger can or multiple cans of sealant in the trunk. Exercise caution when using the applicator, can, and tire inflator, and don't over-apply. Of course, if you've been in a more serious auto collision, prioritize your safety over fixing a tire.

SEE ALSO: How to Choose the Best Motor Oil for Your Car

Is Tire Sealant a Good Buy?

We say yes, since a can of sealant from a reputable auto parts store costs only $5 or $10 and can last months, or even years, when used minimally. For minor puncture holes caught in time, less sealant can mean more and extend the life of the product, and possibly prevent you from plunking down money for a new tire. We would still recommend carrying a spare tire in your trunk, as sealant should be a temporary fix before a flat tire becomes a serious problem.

Readers, what do you think are the biggest pros and cons of tire sealants? Have you used them on your own tires, and if so, what was your experience like? Let us know in the comments below!

Contributing Writer

Paul Sisolak is a freelance writer who covers a wide range of topics, including personal finance, automotive reviews, travel, news and trends, entertainment, and education. He has written and reported for U.S. News & World Report, Business Insider, Huffington Post, CNN Money,, and
DealNews may be compensated by companies mentioned in this article. Please note that, although prices sometimes fluctuate or expire unexpectedly, all products and deals mentioned in this feature were available at the lowest total price we could find at the time of publication (unless otherwise specified).
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2 weeks ago, after a period of slow leaking, I put a can of Fix-A-Flat in the rear tire. I immediately drove about 1 miles at 35 mph then drove 15 miles at highway speed. Ever since then at highway speeds, I feel I'm driving over small rumble strips. The ride is very rough. Could the Fix-A-Flat made the tire out of balance, causing the shaking?
Good article. A couple of things that need mentioning. One obvious problem keeping spare cans in your car is that you don't really want the cans to freeze. The quick summary here is that if you have a newer tire don't use the sealant, get out the spare. Sealant is perfect for older tires. The shops won't repair them anyway if they are anywhere near the wear bars. The article is incorrect that sealant can ruin your wheel "alignment." Paul meant to say "wheel balance" and then only if it is not done properly. It will not affect your sensors either, just follow the directions on the can. One can will usually only put about 15 to 18 lbs into a dead flat tire which will give you a run flat failure if you drive too far. It is a good idea to keep a 12V pump and tire repair kit in the car if you drive long distances in rural areas.
I've used it, and it worked. That's when I learned the BIG disadvantage of using sealants: It voids your warranty on most major manufacturer's tires. If your tire is still covered by warranty, and the vast majority are, you really should not use a sealant. It's not worth it.
Probably got flat in the first place because of those dangerous tire pressure valve stem caps DN is always recommending cause they care more about $$$$$$ than safety of their readers.
do not use unless it is an extreme emergency.
It will throw your wheel out of balance, and cost much to clean it out later.
Some valid points. You need to take into account safety and convenience, being stranded can go from bad to worse in a hurry, and these cans can be a life-saver, even if you end up needing to buy a new tire or sensor for $100. The key is to apply just enough sealant to plug the leak, and no more. When using sealant, make sure the wheel is rotated so the valve stem is at or near the 6 o'clock position, that sends sealant down and get more on the interior of the tire, rather than the wheel hub. Next, drive the car as soon as you can, centrifugal force will spread the sealant to the interior surface of the tire, and keep it off of your sensor and wheel. If you can, use a little sealant then inflate the tire with air. I've not heard of shops refusing to repair a sealed tire, but plugging a leak in the tread is not a difficult DIY, you can find repair kits usually near where the sealant itself is sold, and it takes only a few minutes.
Pretty much a no brainer for vehicles without TPMS and trailers. Often times the spare is low of air and the spare in a can is excellent backup. Small 12 volt air compressors are now available very cheap too. I have one that is included into a backup car starter with light and 120 volt invertor. Hundred dollar investment made waking up to a dead battery a minor issue on vacation and used the compressor to inflate air mattresses and the invertor to charge up a couple phones.