Do a search on "W124 radiators" and you will get a wealth of information!

The inlet neck on the OEM radiator is prone to cracking, the most common failure for these models. And yes, the upgraded versions contain a metal reinforcement sleeve.

I don't know about the 1 or 2-row configuration, but your replacement should be a Nissen or Behr product. I replaced mine 100K miles ago with a Behr unit, and no issues since.

You can probably do just as well buying the radiator here (click on Buy Parts at the top of the page), and you would be sure of getting friendly service, fast shipping and a quality replacement!

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car