Can an expansion tank go bad after 6,000 miles on 2003 325 BMW?

We bought a 2003 325 BMW Sedan (E46 engine) with about 120K miles. The previous owner gave us a repair copy showing that the expansion tank was replaced at 120,404 miles. at 124,430 miles ignition coil had to get replaced and one of the spark plugs (we replaced all 6 at the same time). We now have about 126,000 miles and a radiator symbol showed up on the dashboard. When the car was cool, my husband looked and saw no fluid in the radiator. We had the car towed to our mechanic who said that there is blockage from the reservoir and says that we need to replace expansion tank. Is this possible that expansion tank would fail after 6,000 miles? any help/thoughts be greatly appreciated.
EB