Disconnect the negative battery cable.

Remove the upper radiator hose and then use a shop vac to suck out some of the coolant.

Remove the cap from the shreader valve and then bleed off the fuel pressure.

Disconnect the fuel lines, both of them.

Then unplug the injector plugs.

Then with a 10mm socket, remove the 4 nuts holding the fuel rail down.

Remove the fuel rails and injectors.

After the fuel rails and injectors were all out of the way remove the throttle body. There are 3 10mm nuts holding it in place. If you have a bracket in the way simply lift the UIM after it's disconnect and then remove the throttle body.

The UIM has 8mm bolts. There is one 10mm bolt/stud holding the EGR heat shield, remove the nut, loosen the other side of the shield and move it out of the way, then you can remove the stud.

Take the serpentine belt off the alternator.

Take the alternator and move it out of the way.

There is a hidden bolt under the alternator

With all bolts out of the way you can lift the UIM off.

If your not changing your lower intake gaskets, skip the next few steps

Remove the EGR tube.

remove the brackets on the front and rear that hold the sensors and move them out of the way.

Now you need to remove the 12 bolts holding the LIM in place. These are 3/8" bolts, NOT 10mm

There are 2 hidden bolts. One on the back right, the other front left.

Be sure to cover the lifter valley to prevent anything from falling in.

No mater how hard you try, coolant still gets in to the lifter valley. Be sure to wipe this up with a rag. I then pour some oil in to the lifter valley to help clear away any coolant.

Clean up all your gasket surfaces.

Put a small bead of RTV in the corners where the head meets the block and place your new gaskets on the heads.

You will also have 2 short rubber like gaskets that run along the edge of the engine front to back. Add another small bead of RTV on top in the corners where you added in the last step.

Lubricate the o-rings on the coolant elbow and insert into the tensioner assembly. Then, carefully slide the LIM onto the other end of the elbow and place the LIM back in place. Using either RTV or GM Pipe Sealant with PTFE put a dab on the lower threads of each LIM bolt as you put them in and start threading them.

Now snug up all the bolts and torque in this order. Half torque, then full torque Note, 5 is not on the diagram, it's below 11

make sure you torque to the proper setting.
LIM bolts are 132 inch pounds
UIM bolts are 89 inch pounds.

Now put everything back in the reverse order.