My 2003 Mercury Grand Marquis (4.6l) has developed a continuous rattling noise in front when operating temperature is reached and the car is stopped in drive with my foot on the brake. I believe I have narrowed down the source of the noise to the Accessory drive belt and belt tensioner. The rattle disappears when I put pressure (either way) on the belt tensioner. The noise also disappears when the air conditioner is turned off.
Can the tensioner be lubricated or adjusted or otherwise fixed?