04 tensioner torque??

2004 serp belt tensioner assembly job . when replacing it is there a specific torque requirement for the bolt ? searching around i see some folks had problems with the bolt backing out a few weeks later . some said it was because of "overtightening". why would overtightening cause it to not stay put? also is the procedure the same on corolla,s as it is on matrix and vibe? == you need to jack up the engine just enough for the bolt to be able to clear the inside of the fender. .