i just got truck back from a buddy who flushed my heater core out and was suppost to look to see why my lights flicker at night and inside flickers also he said was alternator.... and also my belt is making a bad sqeaking noise i've been putting belt spray on it but it stops sqeeling while im spraying it on there and 5 seconds later comes back squeeling again bad

 

You could stop at AutoZone and they can test the alternator for free to verify the diagnosis. If you're sure the squeak is from the belt and not a pulley then replace the belt, but a dying alternator can make a whining sound.

 

more then likely if you are spraying your belt and the sound goes away. either the belt is bad. or your pulleys arnt lined up correctly... i would get your alt tested like rriddle3 said. and im sure theyll test the battery as well..this way youll know your electrical system is all good.. the pulley issue is a common problem for the 5.3L motors where the power steering pulley isnt on the pump correctly.

 

i want to know when those squirley little 5.3's were offered in our trucks?

and i must have missed the part where he mentioned taking off the power steering pully. or any other one for that matter.

besides the possiblility that it's the alt making the whine, you should also look @ the tensioner pully & the idler pully. both are very common to be squealers.

 

They didn't come with a 5.3 just sting a fact could potentially be an issue. And if he's spraying the belt the squeal goes away.I don't remember him posting about a whine noise. Bu yes idler and tensioner are common issues for both sqeals and whines.