Thought I would put this out there. Have any of you used Drano to clean a heat exhanger? I have an old onan genset, which I give little respect to, and used drano to clean the heat exchanger. Several years later, no leaks, works fine. I am now about to clean the heat exhanger on my Ford Lehman. I am using a CLR bath at present. How does Drano sound? Have anyone used Drano on there heat exhangers?