Dear Doctor: I have a 2008 Toyota RAV4 with 175,000 miles. Recently, I noticed that one tire was losing air pressure, at first about 2 psi a week, then 5 psi overnight. Nothing could be found in the tire, and remounting it did not help. It was only after the second trip to the tire shop that they showed me where air was leaking through the inside circumference of the rim itself. Since the rim is steel, there is some surface rust. Could the rim be rusted clear through, or possibly cracked? - John
Dear John: I have seen this before, especially in the Snow Belt area. In some cases I have ground down the rust area and used a two-part epoxy to seal the leak. I have also installed an inner tube, or replaced the rim if needed it is the customer's option.