Thanks for your advice. I'll order a new OEM radiator and new hoses while I'm at it, and I will plan on making it DIY job as soon as the parts arrive. It didn't split at at the neck where the top hose attaches. It has about a 3/4" crack in the flat top surface. I drove it 120 miles yesterday with no noticeable change in the water level ... this is after adding a can of Gunk stop leak.
One last question. The MB radiator on the car is a 140. I couldn't find a reference to the cap spec in my manual. All my other Benzes have 100 caps. Is the 140 cap correct for the 2.3-16?