I can’t follow that idea at all. Rust, being iron oxide, is totally insoluble in water, and I think it will be the thermal expansion/contraction that breaks its grip, rather than water getting into it. The other BIG problem with the idea is getting something as big as an engine up to 130 degrees ! I would stick with draining off, followed by refilling with boiling water, repeated daily until something moves. Getting a Scott engine to pieces when there is a bad piston seizure is VERY difficult, and getting the cylinders off the crankcase may involve grinding through the con-rods via the crankcase door openings !!!
Brian
