A few days ago my serptene belt flew off. I replaced the next day, then i had to replace the tensioner pulley. I started the truck and every thing seemed fine. Then i turned the truck off and inpected every thing and it seemed fine. Then i went to restart the truck and it wouldn't start. I have checked the battery and replaced it and the truck started once and now it wont restart. Do I need to have the alternator checked or is their another problem?

Serpentine/drive belt or belt tensioner. Once off, check the pulley's

You have a few problems here first let's try to help with the belt. If the belt is not put on straight it will shred into pieces by straight I mean aligned with the 2 or more pullies including the tensioner. The steering not being straight means the tire alignment is off this can be sorted by going to do a lazer alignment.

The accessory belt most likely or possibly an accessory belt idler pulley is causing the squealing until the belt warms up enough to stop slipping against one of the pulleys which is causing the noise. Either replace the belt or inspect the tensioner pulley and replace.
You can try to buy "belt dressing" at the auto parts store for a temporary solution. Just spray the belt dressing on the contact surface of the belt it should quiet down for a few days.

REPLACE THE TENSIONER IDLER PULLEY.THE TENSIONER IDLER PULLEY MAINTAINS THE BELT TENSION WHEN IT GOES BAD.THAT WILL LEAD TO LOOSE BELT TENSION CAUSING BELT TO BREAK.

Hello bigfish.

We often see this on the Chrysler vans in the shop.
You will need to check all the pulleys and bearings that the belt runs on.
Alternator, AC compressor, tensioner pulley, idler pulley, power steering pump.
Also the tensioner has a heavy spring in it that keeps tension on the belt and pivots on an aluminum pin.
If it wears it go crooked and tilts pushing the belt off.
All these parts are available through your favorite auto parts store.
I would recommend a Goodyear Gatorback belt if you are replacing it, they seem to work the best.

If you would like further advise with this, please ask me in comments.
Thank you.
KL

Carefully check the condition of the belt, the tensioner, and the idler pulley. I had the same thing happen and once I knew where to look, I could see that my idler pulley bearings were bad (understatement...they were GONE!)

Your idler pulley and tensioner need to look even and straight and not leaning in or out. A sure sign of a problem is if one or the other leans in toward where the tension from the belt would be on it.

The best way to check is to buy, rent, or borrow a serpentine belt wrench to take the pressure off and then try and wiggle the tension and idler pulley. If you feel any play, replace as soon as possible. I dragged my feet and ten days after I heard the noise, my idler pulley flew apart right as I pulled into work.

The chirp is from scale or a glaze on one of the pulleys. If not black or shiney in color clean it with brake cleaner and spray some belt dressing on the pulleys

It appears that either the new tensioner or some other pulley is NOT lined up properly. Check to make sure all pulleys are in alignment.

YOU HAVE WHATS CALLED A TENSIONER PULLEY IN FRONT OF ENGINE , ONE OF TWO PULLEYS THAT ARE SLICK (NO GROOVES). THE TENSIONER PULLEY IS WHAT YOUR AFTER. IT WILL BE ATTACHED TO A SLOTTED BRACKET WITH A BOLT HEAD DIRECTLY BEHIND IT.(LOOKING AT ENGINE FROM FRONT OF VEHICLE ITS USUALLY ON YOUR FAR RIGHT!) FIRST UNLOOSEN BOLT ON FRONT OF PULLEY ABOUT FIVE TURNS , THEN MOVE TO BOLT ON TOP BEHIND PULLEY , AND START UNLOOSENING IT TILL PROPER TENSION IS RELEASED TO SLIDE BELT OVER ALL PULLEYS(USE BELT DIAGRAM UNDER HOOD FOR PROPER INSTALLATION. ONCE BELT IS ON REVERSE STEPS 1 AND 2. TIGHTEN TOP BOLT BEHIND TENSION PULLEY TILL BELT HAS ABOUT A QUARTER INCH PLAY IN IT UP AND DOWN (DON'T OVER TIGHTEN).THEN TIGHTEN FRONT PULLEY BOLT TILL VERY SNUG.YOUR DONE! BELT MAY NEED RE-TIGHTENED AFTER DRIVING A FEW DAYS , BUT YOUR AN EXPERT NOW AND THAT WON'T BE A PROBLEM. HOPE THIS HELPED!

Squeal belts usually mean not enough tension. I have had problem with persistance squeling in the past, the problem turn out to be cheap aftermarket belt that keep stretching and wouldn't maintain proper tension, putting brake fluid or any kind of oily liquid on your belt will make it worst not better.