Dell PowerEdge XE8640 Installation And Service Manual page 93

NOTE: Ensure that the PHM is held parallel to the system board to prevent damaging the components.
Figure 54. Installing the processor heat sink
3. Set the anti-tilt wires to the locked position (outward position), and then using the Torx T30 screwdriver, tighten the captive
nuts (12 in-lbf) on the heat sink in the order below:
a. In a random order, tighten the first nut three turns.
b. Tighten the nut diagonally opposite to the nut that you tighten first.
c. Repeat the procedure for the remaining two nuts.
d. Return to the first nut to tighten it completely.
e. Check all the nuts to ensure they are firmly secured.
Installing and removing system components 93