How to Fix a Slow Leak in a Tire

Most car owners dread slow tire leaks. They can be hard to spot, are sometimes difficult to locate, and can spell the end for your tires if you let them go on for too long. Not to mention that slow tire leaks always seem to strike at the worst possible time. Have an interview for a new job? Slow tire leak!

Fortunately, slow leaks are usually fixable, either by an expert or by you at home. The biggest trick is finding the leak before it gets more prominent and before it can cause more damage to the rest of your tire. 

Finding a Slow Leak in Your Tires

The first thing you need to do to fix a slow leak is to find it. Finding a leak depends on noticing the leak itself and then locating where your tire is leaking. 

Detecting a Slow Tire Leak

Newer cars and most premium models of vehicles will have TPMS or tire pressure monitor system that can alert you to low tire pressure. Some will just detect that one of the tires on your car is under or overpressure, while others will also indicate which tire is having the problem. 

Short of a TPMS alert, most people will notice that their car is driving differently before their tires start visibly showing low tire pressure signs. You might have decreased turning performance, or it might seem like you have to use more gas to accelerate in extreme cases.

Not too long after your car’s driving performance goes down, a slow leak will usually cause visible low tire pressure. You’ll notice that your tires are uneven or that one tire is more slumped than the others. Refilling a tire in this condition is a good stopgap until you can patch the leak or get a new tire, but it’s not a permanent solution. 

The more you have to refill a tire with a slow leak, the more likely the leak is to grow over time. 

Locating the Slow Leak

Finding a leak will usually mean taking your tire off the vehicle so you can search for the leak. Sometimes it might be obvious, like if a nail or screw has punctured the tire and only has a partial seal. Unfortunately, not all slow leaks will be that simple to find. 

One common way to locate small leaks is to fill a spray bottle with soapy water and then spray a thin layer over the tire. The leak will form bubbles in the soap, making it easy to spot the exact location. You can either dry the tire immediately to patch it or use a marker to indicate the leak’s location temporarily. 

If you take the tire off and it doesn’t appear to be leaking, you might have a leak that isn’t related to tire damage or a puncture. It’s relatively common for your tire’s bead to form a leak if it isn’t making a good seal with the tire’s rim. 

Tire rims corrode over time, especially in places that use a lot of road salt since the salt is mildly corrosive. If your tire bead is leaking, there may be temporary solutions available, but ultimately, you’ll likely need to get new rims for the tire. 

Your tire’s air valve stem can also cause a leak if it’s no longer forming a good seal, which is a relatively common problem, especially in new tires and tires that have been in use for several years (regardless of wear and tear on the tires). Fortunately, the air valve stem can be replaced. You might be able to attempt a home repair if necessary, but most tire retailers and mechanics will also provide a professional replacement. 

Fixing Common Slow Tire Leaks

Once you know where the leak is coming from, you can evaluate whether your tire is due for a repair or whether it likely needs replacement. The placement of the leak is critical for this decision. Leaks in the tread of the tire are often repairable if they are relatively small and self-contained. However, leaks in the tire’s sidewall, even small leaks, compromise the tire and mean that you’ll need a replacement. 

Pinholes and small punctures in the tread can usually be fixed with a store-bought patching kit. Tiny holes can be filled with a resin or rubber material designed for patching tires without other materials. 

Valve stems can also be replaced if they start leaking, though replacing air valves takes a lot more skill. The typical recommendation is to take your tire to a repair shop or mechanic if you’re not comfortable replacing your air valve stem. 

Bead leaks are a little different, and it’s about 50/50 whether you’ll be able to fix a bead leak at home or whether it will need to be taken care of by a professional. Like all leaks, a bead leak might be repairable, but it also might be too severe to fix. 

Repairing the bead usually involves taking the tire off your vehicle and cleaning any corrosion on the bead and the rim. Try to be as gentle as possible when you're cleaning off the corrosion. Tires are tough, but you don't want to put any new micro-abrasions or punctures in the tire while you're working.

Once you’ve cleaned the bead and the rim, apply some bead sealer to the tire’s bead. Bead sealer is a specialized sealant specifically designed to fix bead leaking. Most vehicle supply stores will carry bead sealer, and it’s relatively affordable to purchase. However, in some cases, the rim might need to be replaced. 

There's also a possibility that the wheel itself could be causing a slow leak in your tire, especially if the wheel is aging or pitted. Usually, it takes expert evaluation to determine if your wheel can be repaired to stop the leak or if you’ll need to replace the wheel entirely. 

Final Thoughts

Like most car repairs, the most important thing is to catch slow leaks as quickly as possible. Even if the leak itself isn’t fixable, finding it quickly and replacing the tire can help protect the rest of your car, especially your suspension system. 

Knowing how to fix a slow leak on your own can save a lot of money in the long run. It’s essential to make sure you keep a close eye on your tires and your car’s driving performance. That way, you’ll be able to keep your vehicle in good condition for a more extended period of time.