Ok I went to start up my truck today and it started to howl from my engine. When I rev it, the howling goes up. I looked and listened and it seems to be coming from the front top of belt. Any ideas?? Thanks.

 

Tension pulley or A/C compressor clutch could be worn out.

 

Loosen the tensioner (or take the belt off) and spin each of the pulleys (including the A/C) and see which one is noisy or stiff and replace it, if you don't it will eventually lock up and burn the belt off. (then the water pump stops turning and the little red light comes on...........)

 

Also, before taking off belt you may be able to "listen" to various items with a long stick or screw driver pressed aginst your ear. Bad bearings make lots of noise, the stick helps focus on one spot and overcome nearby engine noise. Helps keep your dreadlocks out of the belt pathway (safety first).