My truck ('99 Ram 4x4 5.9 QC) squeals when i start it up, usually only when it is not warmed up, for example, it was sitting for about 8 hours today and when i went to start it up it squealed for about 3 seconds, starts up and runs perfect. What is causing this noise???

Thanks

 

Usually, that sound comes from your belt when it is not tight enough. The serpantine belt is self tensioning, so if it is squeeking because it is not tight, then you probably need to replace it (they do stretch some over time). There is an indicator on the tensioner pulley that will tell you if the belt is no longer the correct tension.

If it is not that, it could be one of your pulleys going bad (bearing).