Remove the four indicated Phillips screws from the front wall of the battery compartment. When working from the left, remove the 2nd, 4th, 7th and 9th screws.
Four 3.25 mm Phillips #000. (Head: 4 mm. dia. x 4mm thick)
There's a trackpad and keyboard ribbon cable connecting the upper case to the logic board, so don't pull the upper case off entirely just yet.
Use a plastic opening tool, an expired plastic credit, or a similarly-thick card to pry up on the upper case, starting in the upper-left corner and working around to the front of the computer.
The upper case is likely to stick at its connection above the front edge of the optical drive. If this happens, first free all other sides, then proceed to pull upward on the upper case from either side of the optical drive opening. Here again, inserting a plastic card, guitar pick, etc. can be useful.
If you stand the base of the MacBook on one end to get a better look, you may displace the four grey plastic clips that hold the right side of the upper case in place. Don't panic. They slide into slots at the top rightmost edge of the lower frame, above the front edge of the optical drive.
During reassembly, make sure the clips on the right side, above the optical drive, click firmly into place. They're different from the clips on the left side, and so normally they require a little firmer pressure to click into place.
While holding up the upper case, pull up the black tab on the connector end of the silver ribbon cable away from the connector's socket on the logic board.
If there is no black tab, you can also use a spudger to gently pry the connector out of its socket on the logic board. This connector is tall, so be sure to pry straight up.
If you happen to break your upper case cable when removing the upper case, we stock the cable individually and we have a guide that makes replacing it easy.
While you have the upper case removed, it's a good time to remove dust, hair, etc. It's best to use a can of compressed air, though if you use a brush, make sure that its bristles are made of a material (usually animal hair) that doesn't generate static electricity, which can destroy electronics.
Upon reassembly, there are 4 grey plastic clips installed in slots running along the top of the frame in front of the optical drive (refer to second and third pictures). These clips must be installed in their slots for their mating tabs on the underside of the right side of the upper case to snap into them.
I love these guides, they have helped me to replace the airport card, replace the keyboard cable and modify the optibay to install a 2nd drive.
The last 2 jobs I have completed were to remove the cooling fan to clean it and the exit of the heat sink and later to remove the heat sink to renew the thermal paste conducting material.
My suggestions would be if you are going to remove the heat sink take out the cooling fan first. This is just because the removal of the heat sink is much easier if the fan is out and it's really not too much more work and when you re-assemble make sure the black tape is really sticking down, if it's not the full cooling will be lost and funnily enough the noise of the fan increases.
I used the guide and had no problems getting to the point of replacing the heatsink. I see how the rear heat sensor (250) clips onto the logic board but for the life of me, I cannot see how the longer sensor attaches. I see two contacts but other than the felt thing, there is no way to attach. . . What did I do wrong. . . HELP. Milt King
To refit the temperature sensors, ensure the cables are rooted under the clips of the heatsink. The connectors then just push down on to the motherboard pins.