i have a 4.2 2003 f150 SC when i start it up you hear what seems to be exspansion noises coming from the exhaust area its pretty noisey when warming up or cooling down and quit frequent once im on the interstate had she reaches operating temp its quite
thanks for any input

 

its normal , bob

 

thanks for the info i even took it to midas they spent about an hour on it and heard the sound i heard but couldn't figure it out you can idle the engine up to about 1500-2000 rpm and it will make that popping tin can sound periodically but can't say what it is.