I thought I was in the clear when I finally got my 26 Touring registered a couple of weeks ago. Unfortunately on the first outing the car overheated after about 20 minutes of driving. Yesterday I finally had time to work on it. Suspecting a plugged HC radiator I took the rad off and took it to a rad shop. The guy was very helpful but said there wasn't anything he could do. I guess they can't be "rodded out". He suggested laying the rad on its back and filling it up with muriatic acid. He suggested a 50% mix and blowing air through it from time to time. He thought I could safely soak it overnight. He said that this is also what they do with rusty gas tanks.
I bought a gallon of 35% solution. I was worried about the acid eating up by radiator so I diluted the acid about 2 to 1, giving me about a 10% mix. I only soaked it about 6 hours.
This morning I temporarily put the rad back on and used the "Chipper Radiator Flush Procedure"
https://vccachat.org/ubbthreads.php/topics/210437I used the rest of my acid and ran through two cycles. I was amazed at the crud that came out. I had about an inch of gray material in the bottom of the pail. I added washing soda to neutralize the acid and there was no fizz at all. I rinsed the system several times with water and once with a washing soda solution. I ran the car for quite awhile and it seems to stay cool. Tomorrow I hope to put everything back together and if the rain stops (we had 4.5 inches in the past 24 hours) I'll take her for a spin.
I'm not sure what the gray crud is. I suspect that since the water jackets were cracked (I stitched them), the previous owner simply kept adding Stop Leak every time it started to leak again. Must have been quite a build up in there.
