To be clear, the fan will likely spin with some force, but if it seems as though there is no resistance, it is shot.
FWIW, my '81 300D had the water pump go at just about that mileage. The failure likely led to the engine's demise since the overheating warped the head and allowed water to spray into a cylinder. Rust followed and compression was lost.
\'87 Mer-B 300D (220,000 miles) (sold)
\'93 Mer-B 300D (173,000 miles) (sold)
\'87 Porsche 928 (101,000 miles)
\'98 Dodge Ram quad-cab (250,000 miles)
\'2001 CLK430 Cabrio (50,000 miles)
Past cars: 1969 mercedes 250, 1981 300D, 1972 220D