[quote="cepx111"]Straight water will allow your engine to run cooler but affords no corrosion protection, quote]
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Consider these possibilities- your water passage may have cast iron (block), aluminum (heads/AN fittings/radiator), bronze (waterpump bearing), stainless steel (intake bolts that go thru), pot metal (water neck). Do you know the galvanic action that occurs with heat and cooling plus the negative (ground) current?
Run something.....