Temperature of FETs

I thought I'd check out the temperature of the FETs on my ESC whilst submersed in oil (i.e. the way they will be running inside the thruster), driving the thruster at full load (about 3 amps), just to see if the oil dissipates most of the thermal energy, and it looks quite encouraging.

The temperature probe resting directly on the FET measures just over 63 degrees C (the ambient is about 23 degrees C today) ..... :)

EDIT: Actually up to 73 degrees now after about 2 hours continuous running but still not bad.