I was driving my 94 Voyager when a girl does a wrong way heading my way and totaled my minivan. My brother loaned a 94 Subaru to me (what a brother!). I hate to complain, but the left rear tire leaks. It has been hot out, so I just kept pumping it up. When it finally cooled down a bit I took the wheel off the car and poured slightly soapy water all over the tire searching for a leak. Never found one. Pumped it up and it was fine. Until the weather warmed up again and then it went flat again. Note: It goes flat while parked in the sun. I should fix this before I return it to my brother. Suggestions?
This leak is likely due to rubber flexibility when it gets hot.
It is possible the rim needs cleaning or replacing due to possible pitting (if an alloy wheel).