85 735i overheating...?

i have an 85 735i that's over heating. The coolant is ful, but for some reason its not gettin the coolant is needs.
would it be the thermostat or the water pump?

ive had some people tell me both.

yes it may be a stuck thermostat that stick in the closed position when they become faulty or it may be your water pump, or a clogged radiator. a thermostat has a wax covering on it that when the wax wearsoff, the thermostat wont operate anymore. when your car is reaching just above the normal operating temp check the pressure in your upper and lower radiator hoses by squeezing them be cautious it may be hot, grab a cloth if so . If you may be able to squeeze both of them with little effort it may be your water pump. if only one squeezes and the other looks to have pressure then I could look at a clogged radiator.

when the coolant temperature gauge is at least at normal operating temperature, turn the heat on full blast. If you do not get any heat, that's a clear sign it's the water pump

also, check the fins in your radiator to see if there are lots of them that are rusted off