How to Check for Slow Tire Leaks?
2 Answers
Pour some water to see if bubbles form. Bubbles indicate a leak at the valve core. Inflate the tire fully and use a soft brush with soapy water to check for pinholes in the tire. Carefully inspect the tire surface to see if any foreign objects are puncturing the tire. The extent of damage to the tire sidewall can be directly observed; severe cases may show cracks or bulges. Remove the wheel and sprinkle water at the junction between the tire and the rim. Bubbles will appear at the spot where the rim is deformed, causing a hidden leak.
I've been repairing cars for decades and have encountered many cases of slow tire leaks. First, don't rush to fix it—inflate the tire to the standard pressure, say 2.5 bar, and leave it overnight to see how much the pressure drops. Once you confirm it's leaking, find a large basin, fill it with water, and fully submerge the wheel. Slowly rotate the wheel and observe where bubbles appear—that's the leak point. Common causes include punctures from nails, loose or corroded valve stems, or rusted/warped wheel rims compromising the seal. Adding some soapy water to the basin can make the bubbles more obvious. Rim issues are often overlooked, especially with older wheels where long-term salt corrosion can damage the seal. For prevention, use a tire pressure gauge monthly to check pressure and avoid sudden blowouts during long trips. If the water immersion method doesn't reveal the leak, it's best to visit a 4S shop for a professional inspection—they have specialized equipment for a more thorough check.
