A Stirling engine assembly comprising a Stirling engine having a generally cylindrical head. An annular burner surrounds the head and defines a combustion chamber between the burner and head. An annular seal between the burner and head provides a seal for combustion gases. A thermocouple housing is in thermal contact with the head and sealed from the combustion chamber. The thermocouple housing extends out of the combustion chamber, with the interface between the thermocouple housing and combustion chamber being sealed. The thermocouple housing has an opening outside the combustion chamber. A thermocouple in the thermocouple housing extends from a location adjacent to the head out of the opening in the thermocouple housing.