Unscrew 8 T10 screws from the cooling unit. NOTE: these screws are acctually allen keys. The prefered tool will be long handled allen keys. t10 are 2.74mm (closest allen key is 2.5 or 3mm) and t15 are 3.27mm(closest allen key is 3mm and 4mm). You may strip your tool or the actual screws themselves. Use a set of high quality long handled allen keys.
The screws will loosen but will not come out, they are designed to loosen the unit, but remain in place.
The last two images show another version of the LCS (out of the computer) in the G5 with off-center views to show the 8 screw holes.