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Join Date: Nov 2017
Location: Sioux Falls, SD
Re: 66 Malibu Heater Core and Box Refresh
I received a message asking about the heater box and Evaporust. I had meant to mention both topics earlier.
One thing the rebuild/gasket kit mentioned was to drill out the spot welds of the heater box. That will allow you access the flaps on the inside. I didn't replace those pads because they were in good shape and I didn't want to drill out the spot welds. After drilling them out, it's recommended to use pop rivets to seal it back up.
As for the Evaporust, after experimenting with a one gallon jug on smaller pieces,I purchased a 5 gallon bucket of the stuff. I then poured all 6 gallons into a slender plastic garbage can to soak overnight. Only about half of the heater box fit into the garbage can. After it soaked, I would rinse off that half, remove some paint and rust chunks, then dry it and soak the other end. I actually did this twice on each end. You need to dry it immediately after rinsing it with water, otherwise it will flash rust.
1966 Malibu 327 200-4r