[tubman]

To Kahuna (and anyone else who may be interested), I did a final few runs and a flush with water this afternoon. The "Rust911" solution came out grayish black, I then filled it with plain water, ran it again and drained it. The drain water came out yellow (about the color of pee), so I figure I must have most of the rust out. I pulled one of the thermostat housings, and the inside surface of the head I could see was black. From what I understand, this is residual carbon leached out of the iron when the rust ions are removed. I tried to scratch it to see if there was any rust under it, but there doesn't seem to be. Looks to me like all the rust is out of the cooling system. I didn't take any "before" pictures, but trust me, the insides of the heads were orange with rust.

One other thing; I have seen several places where folks suggest putting nylon stockings or some other filtering device in the radiator hoses to catch the chunks. I didn't look very hard, but I couldn't find anything in the way of sediment etc. in my drain water. Looks like this engine was pretty clean.

Below are some pictures of the "Rust911" being drained, the flushing water being drained, and the inside of the head under the thermostat housing. In the final analysis, I think this was a worthwhile procedure.

Edit : Oh, one last thing. In my previous post, I said that the filtered "Rust911" solution seemed to work. I think that was wishful thinking on my part; on closer inspection of the bolt I soaked, most of the improvement seemed to be from just washing off the dirt. A rusty screw I put in at the same time showed no improvement whatsoever. Too bad.