overheating on 1999 BMW 328i

I just replaced the expansion tank. veh overheats. top hoses and fluid in tank are cold, while the rest of the veh overheats. is it the thermostat?

1 answer
E36 six cylinders a prone to thermostats, blocked radiators, air locks and mostly water pump failure. Remove the water pump and re-assess, the impeller separates from the shaft and no longer provides circulation.