hey everyone. i took my ford truck (f150, 2002 4.2v6) ok so i took my truck to our local ford dealership for a concern i had. the problem was i was hearing a "rattling" noise coming from my truck. now i told this happens when the truck is at rest or at a cruise pace, roughly the noise happens at 1 to 1.2 rpm's. anything over that and the noise goes away same thing if it goes under 1 rpm. so i leave it there and i ask for a copy of the report. it stated ""REMOVED ROCKS TRAPPED IN CONVERTER SHIELD OK THIS TIME" so i'm all super happy that the noise is gone. turns out about a week later to my suprise the noise is back. and again i take it back to the ford and they tell me the same thing. now for the 3rd time i will take my brand new truck to the ford to correct the same problem. so what i'm asking here is what is a converter shield and how do rocks get in there? another thing will this affect my truck in any way because i do not want to drive it if it will cause any further problems. and one last question to all your ford fix it people is this really the cause of the rattleing noise? i would appreciate any repsonce and i thank you for your time.

 

They're referring to the catalytic converter heat shield. It's a piece of stainless steel welded to the converter which goes between the converter and the floor boards to reduce the heat in the cab. Stones trapped in there are harmless but the noise would be a genuine nuisance. There might be a TSB on this if it's any kind of a common problem, have the dealer check.

 

Sometimes the weld will break loose, making the converter shield rattle. A common fix is to tighten a large hose clamp around it.