have a 2000 x5 with M62 4.4i, water pump grenaded on my wife on the freeway and overheated, don't really know the exact details of how long it was overheating, no more than a couple minutes, she pulled over right after the low coolant level beep on the dash display, but it was steaming. Replaced the water pump, thermostat, and belts, filled back up with coolant and drove but after a couple mins it was steaming again. Filled back up with water, made sure thermostat was opening, once it warms up coolant just flows out of expansion tank, but not with a bunch of bubbles, and there is no white smoke out of exhaust. Possibly drove with a little less power, but couldn't tell if I was just being paranoid, if I were to guess I would say 90% power. Does this sound like a blown head gasket?? Will check oil today, and hopefully be able to check compression.