Overheating

I have a 2000 328ci with a overheating problem. The head gasket was
checked 1st and that's good. I replaced the radiator and thermostat. It was
flushed and proper amount of BMW coolant was added. With that all said
my problem is guys that its still over heating. When I start it up there is this
electric sound. I was told it sound like a jet starting up. It heats up really fast
(when driving) to the middle of the gauge for a short distance. Also while still
in the middle of the gauge the overheating steam will start peaking out of
the hood. Then after that short distance it will got in the read really fast. I
open up the hood and see some coolant spray on the passenger lower side
by the lower hose and the radiator outlet switch. I have ordered that new. Its
coming in a few weeks. The motor is hot. Also my heat is not working. Any
suggestions on what it could be??? Could it be this sensor gone bad or is
there more to this? This overheating has been a issue since I got it.