I have a 2004 F250 with 217,000 km that i purchased a year ago and have only put 40,000 on myself. It recently has started a ticking sound and almost a squel the squel is not constant though just off and on but the ticking seems to get louder as time goes on and it sounds like it is coming from the van belt, water pump area. I'm not to sure what it could be i have read about the cam phaser issue with this engine but my mechanical skills are limited.

 

I don't think the 2004 SD for the cam phasers. Just the F150's. Could be a idler pulley bearing or alternator bearing. Try removing the belt and spin all of the accessories to see if any feel rough or make noise. I have also heard an exhaust leak at the manifold lead when the studs break.