For access, remove:
Please perform the following steps as shown in the pictures below:
When installing: Make sure that the connectors are attached firmly.
Note: Loosen the screws [4a] to [4d] in order, but do not remove them. Some models do not have screws . For those models, skip the step 
When installing: Before you attach the fan assembly to the computer, apply thermal grease, at an amount of 0.2 grams, on the parts marked [a] as in the following figures. Either too much or too less application of grease can cause a thermal problem due to imperfect contact with a component. For the new CPU thermal device/fan, you need to peel the thin film off from the rubbers marked [b].
For Switchable Graphics models:
For Integrated Graphics models:
For Workstation models: