A probe assembly for a test fixture for a heatsink, may include a thermocouple probe configured to measure a surface temperature of the heatsink. The probe assembly may include a base portion with an opening for receiving the thermocouple probe. The probe assembly may include a spring-loaded collet assembly connected to the thermocouple probe via the opening of the base portion and configured to cause the thermocouple probe to removably contact a bottom surface of a pedestal of the heatsink. The probe assembly may include a thermocouple cable connected to the thermocouple probe and configured to communicate the surface temperature of the heatsink.