How do you loosening the tensioner pully?

Below I have given you a picture of how the drive belt is routed around the different pully's. Pully number 8 (the one marked with a red arrow) is your belt tensioner. It is spring loaded. On the pully itself is a 15 millimeter bolt. Take a 15mm wrentch and rotate it counter clockwise (away from the belt) to loosen the tension. This will make it loose enough to remove the belt off of one of the pully's and then remove the belt. It should have quite a bit of tension so you may need a long wrench or some sort of a pipe to go over the end of the wrench in order to give you better leverage in order to loosen the tension. Hope this helps....

1 remove battery cables from battery 2 disconnect wires from alternator 3 loosen belt with the belt tensioner it will probly take a 3/8 drive ratchet to loosen the tensioner by putting the end that normaly goes into socket into a square hole in tensioner( just move tensioner far enough to slip belt off alternator pully) 4 remove bolts from alternator 5 put new alternator in place and put bolts in 6 put belt back over pulley 7 plug wires back on alternator 8 reconnect battery

the serpentine belt drive system has a tensioner pulley losing the bolt wont help you have to put to belt on as it shows on the diagram on the fan shroud while rotating the tensioner to loosen position hold pressure on it put the belt over all the pullies then on the tensioner once the belt is around all the pulley and the tensioner rotate the tensioner to tighten the belt...hope this helps

there is a tensioner as you face the engine on the left side, install the belt around the pulleys using the underhood belt routing. using a 3/8 ratchet pull the tensioner and then put the belt on thealternaor pully.

Firt - study & write down (draw) the belt path,,
and be sure about it..

Then - put a wrench on the nut in the center of the tension pully.. Move the tension pully to loosen the belt.. Pull belt off..

Repeat to put new one on..

Should be pretty easy..

There shouold be a tension pully.. This pully keeps tension on the belt..
Put a wrench on the nut at the center of the pully.. You should be able to put pressure on it to move it and releasing the tension..

first you need to figure out if you have an automatic tensioner or an adjustable one. so look at the pullies which ones are not accesories (ie not an alternator pully, power steering.) some pullies will just be on there own not driving anything. is this pully connected to something like this O>o <--this end is the pully.
pully mounting bolt ^ ^arm with hole for rachet
or does it look like the pully is attached to a threaded pole.

the auto adjuster need a rachet to pull back on it (because it's spring loaded) while you install the new belt.

the other need the nut on the pully loosened and the threaded pole loosened will move the pully removing tension from the belt (opposite will tension the new belt).

tighten belt until you can only twist it in half.

One way you can usually tell is that the tensioner base mounts to engine with a bolt in the center of the casting, & pulley is offset from that casting. Put your wrench on the offset pulley bolt to relieve tension. There are various set-ups on that engine so maybe we better confirm which engine it is ?

well has soon as you loosen and take out the alt the belt will become loose then put alt on it will slide down to put belt around and then pull up on alt and tighten it up

That bolt keeps the belt tensioner on. There are two bolts on a typcial tensioner. One to keep the pully on, the other to keep the whole asembly on. Since it's a GM, you should either see a square hole, around 3/8 in or a raised slot. You can put a 3/8 braker bar in the hole and you push it to remove the tension. No need to remove any bolts. Or, there could be a slot sticking out on it, you can put a wrench on it and push it to remove tension. When there is no tension, you slip off the belt from any pully, i prefeer slipping it off a top pully for easier access, and same for instaliton. Set the new bet up the way your old one was exepct for the highest pulley, remove the tension from tensioner, slip belt back on last pully and let the tensioner do it's job. If you remove the bolt that keeps the tensioner on, it will pop off and easily hurt yourself. After the new belt is on, make sure it is on correctly. There are small ribs on the inside of the belt, if those aren't in the groves properly of all the pullies, the belt will not last as long.