It may be necessary to soften the thermal paste between the logic board and heat sink. You can soften the thermal compound using a hairdryer. Move the hairdryer back and forth over the ribbed metal section of the heat sink. At this point, the heat sink should come free easily.

If necessary, use a spudger to pry up the heat sink from the left side near the hard drive.

While lifting straight up on the hinge grill with your right hand, lift the heat sink with your left hand from the end nearest the hard drive and remove the heat sink assembly from the computer.

The hinge grill is held captive by the display assembly/clutch cover, and can only be partially raised.