HOW TO CHANGE THE ALTERNATOR PULLEY
cant take credit
1.Disconnecting battery
Move to the trunk to disconnect the negative battery cable from the battery. Start by lifting
the carpet liner off the battery. Loosen the 10 mm (5/16” on Ion) nut on the battery cable and wiggle the cable off the battery stud. Wrap the cable end with a rag and place it on the floor.
2.The supercharger removal starts with removing the inlet duct that connects the air cleaner to the throttle body. On the Cobalt, this requires loosening two 8 mm hose clamps at each end of the hose; the Ion has 7 mm bolts on these clamps. Start removing the hose by pushing it off the throttle body flange as shown.Pull the hose up off the air cleaner flange and out of the vehicle like this. Remove the brake booster hose on the housing of the blower. The detail photos (middle and right) show you how to compress the two tabs on the bottom side of retainer and push the tabs out the side of the retainer housing to allow the retainer to be gently pulled off the flanged fitting attached to the blower housing.Remove the evaporator-purge hard line fitting by rotating the tab downward on the fitting to unlock it from the nipple on the solenoid. Take a look at the photo on the right to see how the fitting locks on the nipple. Remove the vacuum hose for the EVAP purge line from the nipple on the throttle body by rotating tab downward on
the fitting to unlock the fitting and gently pulling it off. Remove the map sensor electrical connector by lifting the lock tab and pulling connector off the blower housing.
Remove the two 10 mm bolts that hold the coolant reservoir for the intercooler.
Use a hook tool to assist in getting the bypass hose to slide off the nipple of the boost bypass solenoid near driver’s side of cylinder head of engine.
You can either disconnect the electrical connector on the bottom of the throttle body (not easy if you haven’t done it before), or disconnect the four bolts holding the throttle body on the supercharger body.We’ll show you the throttle body removal. To start, remove the four 10 mm bolts holding the throttle body on the supercharger.As you remove the throttle body, capture the red O-ring that seals the throttle body to blower and place it in a safe location for reuse. Place the throttle body off to the side in the engine bay.
3.Moving over to the pulley and belt area of the supercharger, now is the time to release the tension on the drive belt by placing a 15 mm open-end wrench or a “flank drive” open-end wrench on the belt tensioner.I use a tensioner tool from pulley boys store.
http://www.pulleyboys.com/cobalt-ion.html 
The tensioner is cast and sometimes hard to “grab” with a regular open end wrench, but the flank drive wrench will help considerably. Slowly push down and back toward the firewall, as the hydraulic tensioner depresses, until the tensioner bottoms out. Then carefully work the belt off the supercharger pulley with your hand.. Remove the four 6 mm bolts holding thesupercharger onto the intake manifold. There are two little black plastic “guides” that nest in the top of the supercharger bolt holes. Make sure these don’t get lost as you’ll need them to reinstall the blower. Helpful Tip: One trick many people servicing this vehicle do to keep all the parts in one place is to place all the fasteners and other parts up on the cowl of the vehicle as you remove them. You can also place everything in a tray on your workbench—the key is to put everything in one place. Carefully lift the supercharger out of the engine bay making sure nothing falls down into the opening in the intake manifold. As the blower comes off the intake, maneuver it toward the driver’s side of the vehicle to clear the radiator hose. This is one of the two black plastic guides that nest in two of the bolt holes on the blower. Be careful to not let these drop into the intake upon supercharger removal. They hold the supercharger bolts. ECOTEC 2.0L 69 These two metal locating pins seat in the intake manifold (arrows) and have a tendency to stick to the blower housing. Make sure they don’t fall down into the opening in the intake! If the pin(s) stay in the blower when it is pulled out, pull them out and reinstall them in the intake. Place some tape or a rag over the intake opening to minimize chances of something falling into the engine. It is a good idea to make sure the supercharger bypass seal is still in place on the intake manifold and that the metal guide pins are installed in the intake.
5.Compress the clamp holding the lower radiator hose on the radiator outlet and peel the
hose off the outlet. Expect some coolant to find its way out of the radiator at this point,
so have a drain pan and some rags ready to catch the remaining DexCool that comes out.
6. Loosen the 15 mm nuts on the alternator,you will see two in the upper base and one in the lower area.like the pic.Also you will see a cable and plug in the right of the alternator,use a 10 mm too loose the cable and unplug the wire hardness.
7.Remove the alternator from the car is not easy but figure out a little.
8.you will see a cover in the pulley area,use a little screw to take off that cover.
Use a Impact wrench, is a must when doing this.
On the 2.0 LSJ you need a 17mm hex allen socket, turn clockwise to remove the whole pulley.
Use a crew to stop the inside fan in case the net doesn't came off.
the pulleys look like that and also the mrz pulley efficient.
this is the old alternator pulley
9. place the MRZ pulley like the photo and push to the end.
10. With a 21mm tight the nut in place counterclockwise.
Change LSJ Alternator pulley 
Linear Mode
