Lenovo ThinkCentre M55e - Manual (Page 23)

3. Remove the fan plenum from the heat sink and fan assembly. See “Locating
components” on page 3.
4. Depending on which heat sink you are removing, do one of the following:
a. Pivot the handle 1 to release the heat sink clamp and then disengage the
clamp from the plastic retention bracket.
b. Remove the four screws 1 securing the heat sink and fan assembly to the
system board.
Note: You might have to gently twist the heat sink to free it from the
microprocessor.
5. Lift the heat sink and fan assembly off the system board.
Chapter 2. Replacing hardware 15