Originally Posted by Simple guy
you'll be fine flushing with a garden hose. there will not be enough time for minerals to collect and corrode parts, like boiling water in a pot.. boil too long a film of mineral deposits appears... Just make sure all the garden hose water is fully drained. pouring water into the radiator with the lower hose off will only drain straight down through the end cap and onto your feet.
just don't run the engine too long because plain water doesn't have the lubricant for the pump.
having the heat on full blast does nothing besides letting you know some water has made it to the heater core. your climate control knobs DO NOT affect the flow to the heater core.
Nailed it and good info. In the past I have used the garden hose to flush the system without any problems.