EMI-compatible mechanical temperature threshold sensor

A fluid temperature sensor may include a housing having an inlet, an indicator coupled to the housing, and a container disposed within the housing. The container may include a thermo-sensitive housing containing a thermal sensing element. The thermal sensing element may be configured to expand in response to reaching a threshold temperature thereby moving the container from a closed position to an open position. Fluid may flow through the inlet and fill the housing in the open position of the container to actuate the indicator into an activated position.