How to Find a Tire Leak

Finding a tire leak can help stop a gradual reduction of air pressure in your tires from a slow leak, that could leave you stranded with an unexpected flat tire. Follow these suggestions to find minor tire leaks that could cause major problems.

Step 1:  Check the Air Pressure of Your Tires

You may have a tire with a slow leak without realizing it. Use a reliable tire inflation pressure gauge to check the air pressure of all 4 tires regularly. If you notice that one is always lower than the others, you may have a slow leak.

Remove the low-pressure or flat tire from your car and replace it temporarily with your vehicle's spare tire.

Step 2:  Inspect the Tire

Examine the entire tread, sidewalls and bead of the tire. Look through the magnifying glass for any cuts, cracks, splits or objects embedded in the tread that have caused punctures. Circle any likely trouble spots with a bright yellow or white china marker, a kind of oil marker that adheres well to rubber.

Step 3:  Re-inflate the Tire

Use your air compressor, or go to a service station with an air pump, and fill the tire to just over 30 psi. Confirm the pressure with your tire pressure gauge. It should hold for the few minutes the leak test will take. Listen for the high-pitched hiss of air leaving the tire at any of the trouble spots you marked. If you can narrow down which it is, mark an arrow at that spot.

Step 4:  Spray on the Bubbles

Use any kind of spray cleaner, window cleaner or make your own from a few drops of dish detergent mixed with water in a spray bottle. Spray around the tire tread 1/6 of the circumference at a time. When you see bubbles come up out of the tire anywhere, you have found your leak. Circle the locations - there may be more than one - with your china marker.

Step 5:  Plug the Tire and Take It In for Service

If the problem is a tiny hole, smaller than 1/4 inch across, you can do a temporary repair with a tire plug. Remove the object that created the puncture with the vise grips, create a smooth, uniform hole with the tire reamer and insert the tire plug. Redraw a circle around it with the china marker. If the tire's tread and sidewalls are in good condition, take the tire to a tire service center for an interior patch. If the tire's tread indicators are showing, or if the sidewalls are damaged along with the tread puncture, discard it and buy a good-quality replacement tire, either new or pre-owned. Have the tire center install the new tire, put it on in place of your spare, and drive home.

Check your tire pressure monthly during the year, and weekly in spring and fall, to catch slow leaks.