Originally Posted By: KenO
Originally Posted By: 901Memphis
My cooling systems are never clean enough for 50/50, i always end up doing flushes every 2-3 years. I guess it doesn't help that both of these cars are known for cooling issues, the buick for sludgeing the overflow tank and rad neck, and the Taurus for plugging heater cores and cracking pressurized tanks.
Are you guy who are buying 50/50 ONLY using for drain and fills?
Whats wrong with flushing and refilling with 50/50? Use your hydrometer and make sure the freeze point is plenty for your area. Otherwise - antifreeze is a terrible thermal conductor, water being about the best.
The issue lies in some cooling systems, or if you don't pull the block drains. There's often enough trapped water in the system that flushing and then just adding 50/50 could give a mix as weak as 25/75, which is pretty weak in terms of corrosion protection, even if it's not a cold area.