Halo Bro,
Keep on "banging" table at TC till the problem solves... :) Btw, in order that the SE knows wat is ur problem, u can request them to drive out your car around n listen to the sound (if they cant hear it at the service bay when ur car is running). Once they hear the sound, they shd b able to solve for u once n for all.. :) Remember is ur right to bang table, and of cos TC has to solve ur problem in order to retain the customers in the future.. :)