Waste Gate Actuator
From WikiLEC
This is the wasegate actuator
It bolts to the turbo housing via three bolts (green arrows). The capsule (yellow arrow) converts pressure/vacuum to linear motion in the actuator rod (red arrow) to turn the wastegate shaft (purple arrow) thereby controlling the amount of exhaust gasses by-passing the turbo to control the level of boost.
The wastegate often sticks and needs releasing Link title
