#1 cylender spark plug is wet with anti freeze
My guess would be one of three, intake gasket,head gasket or possibly a cracked head.
If you decide to use a pour in rad sealer to seal it up I would leave the spark plug out and run it for 30 mins. with plug left out this doesn't create compression in the cylinder and will allow product to seal it up if it will work at all. Remember this is just a quick temp fix.
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