96 740iL - Running hot

my 96 740il runs hot after runing for a couple miles, the temp guage moves over toward the red and then return to normal after a few seconds, this happens continuously every eight minutes or so. I've replaced the thermostat three times and just replaced the radiator. The upper hose to the radiator gets very hot while the lower hose remains cool, this causes the overflow tank to boil over. What could be my problem and a remedy? PLEASE HELP!

It sounds like you either have a huge airlock in the coolant passage or you have a split headgasket...

Are there any other symptoms that would accompany a split head gasket? Would a bad water pump cause this?, because it seems that my coolant is not circulating. Where could I find a cooling system diagram for this vehicle?

have you ever had the water pump replaced or maybe the previous owner done so? if not, they usually go out every 100000 miles or so, as far as what other owners have told me. supposedly due to the plastic empeller that the oem water pumps have. i'm told its best to go aftermarket with a steel or aluminium empeller.

Check or change the fan viscouse coupling.