I've tried quite a few of the radiator flush/cleaners that have been on the market in the past thirty some years. I was never really satisfied with any of them, they didn't seem to get the radiator as clean as I thought they should, (looking into the neck of the radiator).
Last summer when I had to clean the radiator of my L175, I tried a couple of old fashioned remedies that I had heard of from old mechanics:
1. straight vinegar. fill the radiator with vinegar and run the engine until it heats up, then drain and flush with water. It worked about as well as most of the commercial flushes.
2. washing soda. Made by Arm & Hammer, found in the laundry section of a decent grocery store. Mix it with warm water then fill the radiator, run the engine for a while to let it circulate. This worked the best of anything I have ever seen, the inside of the radiator actually looked clean. Not shiny copper colored, but it was clean with noscale visible.
I should mention that when I drained the washing soda mixture, I got the nastiest looking stuff I had ever drained from a radiator. Don't let it get on your clothes.
Robert