How to get the correct 50/50 ratio of antifreeze and distilled water

[mark lavrack]

Please Help- I have an American built 2003 Chrysler Town and Country Lx I just purchased. I had very little heat in the van because the person neglected coolant changes. Heater Core were dirty/plugged. So I performed a flush/ cleaning using red devil, which works great. I have great heat now. I flushed this system several times with distilled water to get the red devil out, so now I only have water left in the system. My system holds 16.3qt of 50/50 ratio of coolant. I have rear heat. I know I have to add 8 quarts of antifreeze back into the system. So, when I drained the water Out of the radiator I get about 11/2 gallons or 4quarts. I added pure antifreeze in order to mix with the water all ready in the system. I could only put 1 1/4 gallons of antifreeze back in the van. I would have to put 2 gallons of antifreeze back in in order to get the 50/50 ratio. What is the best way to get this correct ratio. Really don’t want to keep emptying the radiator several time with a 50% mix in order to achieve this correct ratio. any suggestion would be very helpful. Thanks

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[Matt]

The easiest way of getting the 50/50 ratio is buying bottles of 50/50 antifreeze and pouring it in. Next best thing, have full bottle of antifreeze, and a bottle of water, mix them in a bucket, and pour it back into both bottles. If you have any left over, save for you when you need it. Most people go with the first one, premixed.

[mark lavrack]

I understand how to get a 50/50 solution, but how to get that 50/50 solution in the coolant system when most of it is filled with water from a flush. Adding a 50/50 coolant mix until the radiator system is full won’t yield a 50/50 mixture in the system, which is required.

[Paul]

You can use the drain-and-refill method to “dilute” the water in the system with coolant: Drain the radiator, add 1.25-gal of 100% coolant, circulate to mix and distribute the two fluids in the system. If my math is correct, then

• First drain and refill: ~30% mixture.
• Second drain and refill: ~52% mixture.

So, it looks as one more drain-and-refill procedure (with the volumes listed) should bring you close to the 50/50 mixture. It’s probably worth checking the boiling and freezing points of the final mixture with a tester though.

[mark lavrack]

Thanks I was thinking the higher ratio too. Just didn’t know the Percentage. Just bought a tester for this. Was just trying to avoid another drain and fill because I’ve done so many to clean the system to have heat again. Thanks a ton.

[Matt]

If you don’t get the mixture perfectly 50/50, it isn’t going to blow up or something.

[Author]

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