Try Cat for their radiator flush products but there is no substitute for rodding out a clogged radiator.
I used one of the Cat products and it didn't do near as much as I hoped it would.Shortly after this it started leaking around the upper o-rings on the pre combustion chambers.Cannot say they were cause and affect,but I am not inclined to us that type "fix" on my 9u's again.
It is a project to rod the radiator,but the only thing that is not shade tree mechanic friendly about it is broken bolts.I have not had any bolts that I could not remove by welding a flat washer and nut onto the broken part bolt.Many I had to weld several times but once it is all apart the pieces are not that heavy ,so lay them out weld let cool then remove or break weld and start over.I am not the greatest welder so as long as you can weld at all you can do it. I have done it a few,so it wasn't just that I got lucky with the first one. Good luck with which ever way you try.
Thanks for the help guys.
Common problem, flush out the crud and things start leaking.
Maybe ill just leave it 3 hrs is lots out of the old girl.