After an acid flush, I use a box of baking soda dissolved in water to neutralize the acid. Then I follow up with a strong TSP/water flush to take care of any greasy deposits the acid doesn't remove. One more water flush, and then add a 50/50 antifreeze/water mix. A 50% solution has a freeze protection of -37 degrees F. and it preserves rubber parts better than straight water.

DO NOT run straight antifreeze. It does not transfer heat well, and it gets slushy at +9 degrees F. An 80% antifreeze 20% water mix should be the absolute strongest solution to run. A little water in the mix is required to kick off the proper freeze protection.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!