I looked for radiator flush at Advance Auto to do my Benz. They only had 1: Zerex 10 minute Flush. Used it today. Doing the Benz is a pain in the butt because you have to remove the bottom radiator hose to dump the radiator. Had to then do this twice, once to dump old, then to dump flush stuff. Luckily, the block drain is reasonably easy to get to, and there's a nice vent plug on the thermostat housing that allows one to easily fill both the block and radiator and vent off the air there. This is the first time ever that I've ever used a flush. Think if you change the antifreeze before it gets worn out, that you don't need to do so. Didn't on the VW nor the Tacoma when I changed them out this last summer. Usually just flush really well with water only.
The flush stuff didn't get all the little bit of stuff that I could see on the radiator core. Looks like it removed most of it. Unfortunately, it appears that the Benz antifreeze is good for only 2 years as they say and not good for 3 1/2 that it's been in there. Before, at 2 year changes, the radiator core was crystal clear. Whereas, the "permanent" antifreeze in the VW seems to have caused no corrosion the 1st 5 years it was in there. Changed it out and plan to let it go for 5 years now.
Ralph