Q: I recently had four new tires installed on my car. The tires lose about 8 psi per week. Where do you think they are leaking and how can I tell?
A: The bead, where the rubber contacts the wheel, may be leaking on each tire. The best way to look for leaks is to put about a teaspoon of dishwashing soap in a spray bottle and fill with water. Spray the tire, rim, valve stem, and valve core with the soapy solution. As you spray the tire you will see many bubbles from the soap, but look carefully. Eventually the leak will start to blow a pile of bubbles. If the bead is leaking, you can have each tire broken down and the bead cleaned. Then the tire shop can use a special bead sealer to seal the tire.