I have a 2002 F150 4.6 v8 and replaced the tensioner pulley and tightened it good.When i grab it,it has slight play up and down. My belt ripped when i installed it after replacing pulley. Could that be the problem? Thanks

 

What had slight play up and down? The belt?

Did you get a tensioner with the correct amount of grooves? For some reason I remember there being 2 different grooves

 

Having a hard time picturing what you're saying. But I'm assuming you installed the correct pulley. Most trucks had A/C, which use a smooth pulley.

If you're saying that the tensioner itself has play in it, replace the tensioner.

Again, not picturing exactly what you're describing.