AAP on coolant

[mjoekingz28]

'Engine coolant and transmission fluid are two more items that must be changed regularly to ensure a long life for your car. Engine coolant should be changed every two years and diluted with 50 percent water, as pure engine coolant will freeze at around 0 degrees Fahrenheit. This mix gives you the best cold weather protection and the best heat dissipation ability in hot weather.'

on their website
http://shop.advanceautoparts.com/Maintenance/MaintenanceMissedMaint.aspx

 

[StevieC]

I empty my radiator every 2 years regardless of mileage and refill with a 50/50 mix of Glycol based aluminum friendly coolant and distilled water. I also add a bottle of cooling system lubricant and have always driven my cars to the scrap yards with hundreds of thousand of miles and usually original rads and the same water pumps. FWIW

 

[The_Jeff]

That's true, united with water ethylene glycol mix freezes at a lower temp than either itself or its companion water.

 

[Ken2]

In addition, straight antifreeze carries less heat from the engine than an antifreeze/water mixture. Pure water (plus anticorrosion additives) carries the most heat away.