Distilled water vs tap water for your radiator

Discussion in Auto & Moto started by lindbergh • Mar 14, 2014.

  1. lindbergh

    lindberghWell-Known Member

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    For optimum performance, they say that distilled water should be used in your radiator. They say that if you use tap water, it leads to rust. Also, the minerals in the tap water would build up and affect the cooling system of your car. Personally, I only use tap water. I don't want to spend additional money to buy distilled water to put in my radiator. I think tap water is just fine. I haven't had a lot of problems with using tap water so far.

    If you want to save money, I suggest that you just use tap water. If you are very skeptical with the tap water available at your place, then use distilled water. It would cost you much more though.
     
  2. Gelsemium

    GelsemiumWell-Known Member

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    OK... I never mess with my radiator. My car goes to service once per year and I imagine they do that sort of maintenance. I don't even know if all the cars need to have water put in their radiator, isn't it the same water that cools the engine down? (sorry for my ignorance)
     
  3. Lostvalleyguy

    LostvalleyguyActive Member

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    Oh no - not more distilled water mythology.

    The good or bad of tap water will depend a lot on the quality of your tap water - what it contains, and what it doesn't. Hard water, for example, will contain a lot of minerals and can cause deposits in a radiator that can block some of the smaller channels. Even restricted flow can increase the chances of overheating. Acidic water can react with the metal in the radiator and corrode it. If your water is poor, buying a jug of water at the store is a good idea (drinking water not distilled). The radiator should have some antifreeze in it at all times and this can act to protect the radiator as well as alleviate problems with high and low temperatures.

    Distilled water it too pure. Water likes a certain level of dissolved particles in it. If none are present (In distilled water), they will be drawn out of the radiator effectively corroding it.

    Distilled water is a must for batteries as mineralized water can react with the acid effectively weakening it. Distilled water can also pull Lead ions from the plates which are needed for the battery to operate.
     
  4. Jason76

    Jason76Active Member

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    Actually, from various comments I saw on the net, it seems like that a good anti-freeze or coolant solution cancels out any negative effect of tap water. Anyway, I'm wondering what any newbies to this thread put in their radiator. Myself, I usually neglect coolant or anti-freeze, but I know that's a bad move.

    This is the first time I've heard that distilled water is absolute, beyond a doubt, bad.

    This is sort of confusing. I mean, is it good or bad?
     
    #4Jul 4, 2017
    Last edited: Jul 4, 2017
  5. Alexandoy

    AlexandoyWell-Known Member

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    This is a good thread for those who are not well versed with cars. We fill the radiator with purified water because distilled water is expensive and purified water is also safe. Tap water here is claimed to be safe but our water purifier has traces of moss, that greenish organisms that grow into small plant. To be extra sure, we never use tap water for ingesting. Even our dogs are given purified water since we cannot trust tap water here.
     
  6. Happyflowerlady

    HappyflowerladyWell-Known Member

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    We always use a mixture of antifreeze and just regular tap water in the radiator. The antifreeze is supposed to be better for the engine, but when we need to add water, it is easy to just get the garden hose and add a little water to the radiator.
    I don't think it matters whether you use tap water or filtered water, or even distilled water for the radiator.
    The impurities (such as the moss that @Alexandoy@Alexandoy mentioned) should be killed when the water gets hot; but it is still good to have your radiator flushed now and then to get out minerals that might be interfering with the radiator function.