What? The drain plugs OPENED?!? Alert the media! Seriously, that is unheard of. Usually they are so rusted they break or your tool breaks. Yes, a good flush will clean out the junk. I also learned to add a shot of [Cascade] dishwasher soap to the water only system and let it run a while. But it cleans so well, that any pinholes will be opened.That usually means a new radiator or water pump. So I reserve this for extremely filthy systems that need new parts anyway. It is also a good idea to use only distilled water mixed 50/50 with a good brand of anti-freeze in the cooling system. That is mandatory for cars with aluminum engine/cooling parts. But it helps keep rust and corrosion at bay in our old systems too.
