thanks for the input...i can have a look at the heat shield. But I can hear the sound coming from the front left wheel area. It is a sound like metal hitting metal (grating/grinding) and I hear it whenever I am driving on wet roads. I think I heard the sound about twice when rain was not falling, but I would always hear it on wet roads. Whenever I hear the sound, I can feel a difference on the wheel, as though the wheel is under pressure, as though it is being forced to turn. A few mechanics have checked, but they did not see anything that would cause this problem. The sound lasts for just a few seconds.