Originally Posted by Kai
Typical green coolant didn't magically turn evil overnight, Honda blocks from the 70's to today are made of virtually the same grade aluminum. Seeing how unusual it is for water pumps to leak any significant amount as-is, it's not important.
It is perfectly fine to mix in store bought coolant. Properly mixed and changed at the recommended interval, you will see no problems. Honda passenger cars have lived with "evil" green coolant without ill effects since the 70's.
Honda did not start producing aluminum blocks until the F and D series came out.
All previous engines had cast iron blocks.
You are WRONG, if a manufacturer specifies that a NO silicate NO phosphate coolant is to be used in an engine, you must use that coolant. This doesn't only apply to Hondas many others are this way as well. When you mix two coolants of different chemical make ups, bad things can and will happen.
Nearly all store bought cheap junk coolant is made for domestic cars, which up until very recently used highly silicated and phosphated coolants.