Need advice regarding changing coolant

[johnwk]

tmontague: I changed my coolant today following your instructions, but I added a few steps in the middle on a friend's advice. After draining the old coolant, I filled the system with distilled water and some Prestone Flush+Cleaner. Following the Prestone instructions, I drove for 10 minutes, drained it, filled it with distilled water, drove it, and drained it again. Even on the third drain, it was still very pink. (In total, about 3 gallons of liquid came out.) I ran out of daylight and distilled water, so I just filled everything up with 50/50 and called it a day.

Now I have two questions/concerns: since the third drain was still pink, there must still be some of the original coolant, plus some distilled water. Is that a problem, or is this a "good enough is good enough" scenario? Second, I'm assuming there's still some Prestone Flush+Cleaner in there. Is that okay?

Thanks for your help!

[tmontague]

Originally Posted by johnwk

tmontague: I changed my coolant today following your instructions, but I added a few steps in the middle on a friend's advice. After draining the old coolant, I filled the system with distilled water and some Prestone Flush+Cleaner. Following the Prestone instructions, I drove for 10 minutes, drained it, filled it with distilled water, drove it, and drained it again. Even on the third drain, it was still very pink. (In total, about 3 gallons of liquid came out.) I ran out of daylight and distilled water, so I just filled everything up with 50/50 and called it a day.

Now I have two questions/concerns: since the third drain was still pink, there must still be some of the original coolant, plus some distilled water. Is that a problem, or is this a "good enough is good enough" scenario? Second, I'm assuming there's still some Prestone Flush+Cleaner in there. Is that okay?

Thanks for your help!

The method I posted above is simply a coolant drain for those that have stayed ahead of the change interval and have never contaminated their coolant with another type and isn't having any issues with their coolant.

I you want to completely flush the coolant then you can do what you did which will take a while or just remove the thermostat and filled with distilled water and run the car. Don't do this long as the thermostat housing will leak a lot of water without the thermostat/gasket in place. I find this the quickest way to flush the system and get out any old coolant without having to go drive your car around.

To answer your question, the only real issue would be the coolant be too diluted below 50% and it potentially freezing if you live in places that make your face hurt like I do. Easiest way to figure this out is with a cheap $10 coolant tester from a local parts store. Test your coolant and see what its freezing point is to know what percentage it is at. If it is too low then drain some and add more coolant