Appears to be a common problem. Mine, on a '90 300E, split below the neck. Some have suggested that the neck needed reenforcement or that using other than MB antifreeze affects the platic. I personally think that the the plastic material weakens with age and constant exposure to heat. I would be concerned that the present radiator would leave you stranded in the future and possibly damage the engine. I think that excessive temps could at the very least destroy the head gasket. Do a search on radiators in this forum.

__________________
Ken Fuller
1990 300E