Originally Posted by spearfish25

I did a track event this past weekend and after a run, had the car cooling with the engine running and hood up. A guy walked past and said my power steering fluid was boiling. Looking at the reservoir, there was quite a bit of centrifugal turbulence but no bubbles. While he claimed it was boiling, my feeling is the fluid viscocity has dropped so that the circulation is much more apparent. Turning off the engine, the movement in the reservoir stops immediately. Also, starting the car when the engine is cold results in a much smaller amount of turbulence in the reservoir.

Thus, I'm not sure it's boiling...just lower viscocity leading to more noticeable circulation of fluid.