Dell PowerEdge C6145 Hardware Owner's Manual page 120

CAUTION: Using excess thermal grease can cause grease to contact the
processor shield, which can cause contamination of the processor socket.
3 Place the heat sink on the processor. Make sure the guide pin is
inserted through the slot of the heat sink. See Figure 3-8.
4 Using a Phillips screwdriver, tighten the two heat-sink retention screws.
5 Install the system-board assembly. See "Installing a System-Board
Assembly" on page 116.
6 Reconnect the system to its electrical outlet and turn on the system,
including any attached peripherals.
7 Install the air duct(s). See "Installing the Air Duct" on page 117.
120 | Installing System Components