Tire Bead problems of the 2009 Nissan Murano

Cooper cs4 touring tires leaking air in cold weather. I have a Nissan Murano, this winter with the very cold temperatures these tries had to have air added every week. I'm talking about 5 to 6 pounds of pressure. Had them bead sealed but they continued to leak. Posted complaints on Murano web sites and was told by other drivers with cooper tires," the problem was the cooper tires. " had the oem goodyears till 55k and never had this problem. I am posting this now so other people with these tires will check them more often.