BMW: 96 bmw 328i coolent system, coolant system, aluminum head

Question
My car over heats in about 15 min of driving.  I replaced the thermostat and my
water pump is good.  All the hoses are good and there is slug in my motor.  
Besides the head gasket and the head itslef what could it be?  

Answer
Anthony,
 I wouldn't suggest the Headgasket as a reason for over-heating.  The headgasket only comes into play when you allow the engine to over-heat, then pressure builds in the coolant system (steam) and it blows out the weakest point (headgasket).

 Check the fan clutch.  Those are notorious for going bad.  If it goes bad, then the fan wont pull much air through the radiator, and the coolant temps will rise.

 One last thing, NEVER... EVER allow the engine to over heat.  As I said above it will blow the headgasket, or warp your aluminum head.  If you see the temp get to 3/4 (75%) hot, pull over and turn it off.  It's not worth ruining an engine.

 Good luck,
 Josh