Thinking over all your complaints about excessive coolant overflow, "white smoke," low compression in two cylinders, it's beginning to sound like you have a head gasket problem between a water passage and a cylinder. Do you have any water in the oil? It would probably look like thick brown foam. Get your car to a good mechanic, not the bozo who sold you the shiny GM alternator, and have the cooling system pressure tested. Why on earth would you want a "water filter?" You car doesn't need Perrier. --Roger van Hoy, '55DeSoto, '42DeSoto, '66Plymouth, '73Duster, '81 Imperial, Washougal, WA