Heater noises

[alan]

I've got a 99 silverado with 80000 miles.  Just yesterday I was driving along and noticed a loud hissing that would come (accessory belt noise) on for about 10 seconds then go off.  If I turn my heat off the noise would go away?  What does this sound like?

[RyanbabZ71]

is the noise coming from the heater/cooler ducts?  I had a high pitched noise that happened when i turned on the air or heat.  The higher i turned it up the louder and higher pitched it was.  This happened this past summer/fall and on a 2 hr trip to close down our summer cottage for the winter i ran the heat the whole way.  On the way back the noise disappeared.  Has never came back.  My fix was to run the heat for an ext period of time

[nonstop]

Ryan, Mine just did that too this weekend. Freaked the crap right out of me.

 

I just turned it off, and on again, I guess the lube in there got cold or something, but if its turned off then back on its quite again.

[RyanbabZ71]

mine was loud no matter what for a few months.  I didnt even realize it had left until my dad asked why it wasnt making anymore noise hehe  

[CacalackChuck]

I too have just been blessed with this problem.  It sounds as if there is a leaf or some debris in the duct that is making the fan make the ticking noise.  I have owned several Chevy's and this has always been a problem.  In the past, the noise usually works itself out.  If anyone else has had this problem, and had their truck looked at, please let us know what the diagnosis was.  Much obliged