My tire got flat and found out that the leak was from the eroded stem value.
I don't know how stem value got eroded.
Tire seems okay for another 10,000 or less maybe.
I have a Olds Intrigue where the rim was not smooth as it could be in hole and it would leak around the base, I had to take some permatex gasket sealer in with me and give to the tire guy to put on the stem to make them seal up.