Yup, many times.
I don't start off with a chemical flush if the system has been reasonably maintained. I do a series of water flushes only. Use either distilled or reverse osmosis water for all flushes and the final fill.
2 things I'd change from the otherwise very good video:
1. leave the overflow tank cap on and the radiator cap on, open the petcock, and if you're lucky the overflow tank will drain due to the negative pressure created in the radiator by the draining coolant. No need to disconnect the hose if it works.
2. Fill the engine with coolant concentrate through the thermostat opening till full, once you're drained the final flush water. Install the new thermostat, then fill the radiator with concentrate. If you managed to get all the concentrate in (which is 50% of the total engine capacity), then top up the radiator with distilled/RO water. Use a 50/50 mix to top up the overflow tank over the next few days. Most engines will have residual coolant trapped in coolant passages within the block so you're not draining 100% of the flush water. Using a 50/50 mix alone as in the video means you'll end up with less than a 50% final concentration once the residual flush water mixes in.
