How Do I Find and Plug a Slow Tire Leak?

Do you find yourself having to put air in one of your tires every few days? If so, one of your car’s tires could have a slow air leak. That air leak can eventually lead to a flat tire. Fortunately, you can verify when a tire has a leak and even patch it at home.

How to tell if your car’s tire has an air leak

Student Joseph Ziemek patched a leaking tire during an auto tech class.
Student Joseph Ziemek patched a leaking tire during an auto tech class. | Bruce Bisping/Star Tribune

Most modern cars are equipped with a tire pressure monitoring system (TPMS) that notifies the driver of a change in pressure in any of the car’s tires. However, if you suspect that your vehicle has an air leak and it doesn’t have a tire pressure monitoring system, then there’s an easy way to find it.

First, you can visually inspect the tire’s tread and check for any obvious punctures or nails in it. According to Cars.com, a slow air leak can even be caused by a pinhole in the tread or sidewall. However, the air valve stem or an unsecured tire bead could be culprits as well. In order to pinpoint the leak’s location, you can start by grabbing an empty spray bottle and filling it with soapy water.

Next, take your spray bottle full of soapy water and spray all areas of the tire – this includes the tread, sidewall, the valve stem (uncapped), and along the side of the rim. When you find a spot where bubbles start to form, that’s where the air is leaking out. It’s best to do this process with the tire completely removed from the car, but you can do it with the tire still install. You might just need to move the car backward or forward to ensure you’re inspecting the entire circumference of the tire.

How to fix the tire after spotting the leak

A mechanic at a car repair shop in the Lichtenberg district changes a vehicle from summer to winter tires.
A mechanic at a car repair shop in the Lichtenberg district changes a vehicle from summer to winter tires. | (Photo by Wolfgang Kumm/picture alliance via Getty Images)

After you find the leak, you can fix it yourself as long as the puncture is in the tire tread and not the sidewall. Repair Pal notes that small punctures can be repaired as long as the tire has been driven on when flat. To repair the leak, you can buy a tire repair plug or patch kit at your local auto parts store. If you choose to repair the leak using a plug, then you can simply use the tools in the kit and repair the hole with the tire still mounted on the rim.

But if you choose to repair the hole using a patch kit, then you’ll have to remove the tire completely off the rim so you can patch it from the inside of the tire. In this case, it will be wise to seek the help of a tire shop to patch the tire or at least remove it from the rim for you. Also, if a leak is caused by a damaged wheel or a tire bead issue, then you could be better off getting help from the tire shop.

Will a tire sealant repair the leak?

A car service worker fitting winter tires
A car service worker fitting winter tires. | (Photo by Anton Vergun\TASS via Getty Images)

While tire sealants like “Fix-a-Flat” can seal small punctures in a tire, they are mainly meant to be a temporary solution, according to Tire Fever. The real solution to fixing any small tire leak is to have plugged or patched. However, if the damage is too large, then you may just need to replace the tire completely.

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