Everyone recommends distilled because this is safest, pure water and nothing
else. Then add the appropriate ant-freeze mixture even in the summer.
Anti-freeze does not just stop the water freezing, but increases cooling
If you are going to use tapwater, which we've all done in an emergency, boil
it first. This will drive out a lot of the dissolved oxygen and reduce the
hardness a little if limescale is a problem in your area. Reducing the
oxygen content helps reduce corrosion.
From owning a number of vechicles and heavy equipment, replacing
radiators, pumps, hoses and such and having seen the rust and other
minerals in water from running a community well, USE distilled water.
Yes, rust is an issue, but the big issue with tap water is the
minerals. You don't need the metals and other minerals in the water.
They cause the deposit and gunk you see after you have flushed a
cooling system or look at a heater core. With the metal radiators
after a long period of time, they will fail from rust. You will
experience cracks in the metal seams, etc.
If you don't a pure water store in your area, the distilled water from
wal-mart or any other store is fine. If you're going for good tasting
distilled water, the pure water stores are the best. After the water
is distilled, they run through a micro filter. I use to know the
size, but it give the water that clean water from the mountain
Also, for your lead-acid batteries, distilled water is better for the
above reasons. I have brought a good battery like NAPA's and
DIEHARD's back to life with distilled water and a 8 hrs charge.
Your memory must be faulty. The 'good' taste of water comes from mineral
content. Pure water tastes pretty terrible.
Plus -- despite the issue of mineral content -- I am not aware that
purified/distilled water is used in the coolant system. The key is to use
the right mix of water and anti-freeze all year. BTW, very pure water can
dissolve minerals from pipes and containers.
For direct contact replace nospam with schmetterling
I've always used 50% tap water with 50% antifreeze and have never had
a problem with any vehicle. In fact, until this discussion, I have
never heard of using distilled water for coolant, only for batteries,
where I agree, it is important.
I change the coolant every 3 years or so and I think that is far more
important than which type of water you use. All today's antifreezes
have corrosion inhibitors. And the point made about rust being an
issue with tap water is dubious. Rust is formed from the oxidation of
iron. Without corrosion inhibitors, that will occur regardless of the
type of water used.
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