Lenovo ThinkStation 2551 Hardware Maintenance Manual page 167

8. From inside the chassis, pivot the left retaining clip
sensor and then push the clip outward to release the clip. Then disengage the plastic holder holding
the thermal sensor from the chassis.
Figure 98. Removing the thermal sensor
9. Pull the entire thermal sensor out of the chassis.
.
Chapter 11 Replacing FRUs (for machine types: 3688, 3690, 3691, 3693, and 3695)
1 that secures the plastic holder of the thermal
161