How about a recore job if this is possible? Recore is usually about 1/2 the cost of a new radiator and is as good as new. Possibly this is only available for the old copper radiators with brass tanks. Why did they ever go away from copper radiators? Aluminum and plastic radiatore are crap. I could see Ford or GM doing that but MB??????
Have you tried having the rediator cleaned? My radiator shop has a process where they use live steam and it costs about $30.
P E H