Antifreeze/ Coolant - Hard Tap Water Mixing with Concentrated Antifreeze. I used tap water to mix 50:50 ......?

People say you aren't supposed to use Tap water when mixing with Straight Antifreeze. Because the tap water is hard & has magnesium, calcium & other sulfates that cause scaling in the engine & radiator over time.

I mixed mine bang on 50:50 a few years 3 years ago in my 1980s Dodge 2.2L 4cyl.


4 Answers

  • 1 decade ago
    Favorite Answer

    The whole object of car maintenance is to put your best foot forward. For that reason distilled water DOES belong with your 100% antifreeze mixture. Tap water is loaded the items you listed above plus iron which causes a mess in the entire cooling system.

    The first person who answered your question probably dumps tap water in his car battery.

    Source(s): Alignment, suspension and brake shop.
  • 1 decade ago

    Radiator companies do studies, and any impurities in the tap water can affect the antifreeze when you mix them together. However this is one of those long term things, just as an example, I had two similar year vans, the first radiator after about 20 years started to leak from a seam. So figure life span of a radiator is 20 years, second van, radiator sprung a seam 22 years, pretty close, so here is the deal if you want your radiator to last 30 years, you can use distilled water, and antifreeze, but since most of us never keep a vehicle that long, more than likely whatever goes into the radiator is tap water, my take I use antifreeze and distilled when I put in a new radiator (or water pump) or thermostat and then use tap water after that as necessary. The radiator company did studies at its manufacturing companies across the USA and did fine some states and cities, had pretty good tap water, and some had really contaminated tap water, compared to other states. So personal preference is a choice, and that depends on how long will you keep your car ? usually elecrolysis (this is a chemical reaction between two metals) would eventually find a weak spot in a radiator, for many years radiators were made from two different metals, which did not help. I bought a aluminum radiator this time, it is suppose to cool faster, and if it lasts 10 years I would be happy, but hopefully it lasts 30 .

  • 1 decade ago

    Yes, it is. I had the tanks off the radiator of a Volvo we had bought that had just one coolant change, and it was apparently done with Phoenix tap water. The bottom third of the tubes were plugged solid with hard water deposits. I recently changed a radiator for a friend; his 2000 Focus had the proper coolant mix but the radiator was so plugged with hard water deposits I could hardly blow any air through it.

    Purified (deionized) water is pretty cheap at the supermarket and I consider the use of tap water to be an emergency measure only. In your case, though, if the radiator is the original the plastic tanks are probably about at the end of their life expectancy, so I wouldn't worry about it too much. If you don't use tap water again the radiator will probably crack before it plugs up.

    Source(s): 35 years maintaining my own cars
  • Anonymous
    1 decade ago

    50/50. Tap water is fine. Others will chime in with weird ratios and say things like "use distilled water" They are Momos.

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