We arrived at this conclusion from evidence found in both the coolant sample provided from the coolant system at the time of failure, and the careful inspection and disassembly of the radiator itself. Electrolysis, on the other hand, would have been indicated by a surface that was clean and free of deposits and a damaged area that had a weakened, dissolved appearance. This definitely does not describe the damage done to our subject radiator. Both photos show side views of leaking tubes. Arrow points toward the tube welds.
Close examination shows a hint of pinholes along the folded portion of the welded joints.
Shows the cross-section of a leaking tube magnified at 4 times larger than real size. The uneven pattern shows pitting of the aluminum inner surface. A protected tube would look shiny, flat and silver in color. A close-up of the tube in Photo 3 at 40X magnification . It clearly shows tube pitting in a pattern that demonstrates something fell out of the coolant's solution, laid on the surface and started a penetrating attack.