Tire valve stem recall
30 million defective valve stems made in China were installed in tires in the United States from Late September 2006 thru mid 2007. They forgot to add the UV protection or possibly ozone protection and the rubber is breaking down. The valves were manufactured for Dill Air Control Products of Oxford, N.C. by Topseal Shanghai Auto-Parts Co. Ltd. in China.
To be sure if you have one of the bad valves you need to dismount the tire and check the manufactures code on the valve from the inside. The bad codes are TR-413CH, TR-414, TR-415, TR-418 and TR-423. But you can tell if it is cracking by bending the stem and looking for small cracks near the rim hole. See the picture I took of a bad one. It is worth replacing a cracking valve stem even if it turns out not to be one of the recalled valve stems.
Much more info here:
http://www.4x4training.com/Articles/Safety/TireValveRecall.htmlKen
