Today when out cruising the valley I noted that fuel was "boiling" in the bottom 1/2-1 inch of the header tank guage. Air temp was about 80 degrees, oil temp indicating 190-200, altitude 2500-3000 ft. Barometer 30.05 or so. This is not something I have observed in the two years I have had the plane. I could not see any indication that fuel was leaking from the vent, nor upon landing was there any evidence of leakage around the fuel pump. Tanks seemed to be transferring as normal.
Thus my question, do I have a potential problem with partilly blocked fuel return line, in-leakage at the fuel pump, or were conditions just right to actually have vaporization in the header tank. Av gas is blended to a RVP of 7.0 max as I recall just to avoid such a phenomenon. Suggestions and opinions are appreciated. R. Hunter N3000G
