I've picked up a shamefully neglected truck and now I'm paying for it (again).
Radiator had orange sludge runnin thru it-literally- no tellin' when it last contained actual coolant.
I grabbed the upper radiator hose to check its condition - gave it a squeeze and it made this crunching cracking sound like I was crushing tortilla chips or balling up some thick, crisp paper. ...."hmm- that hose is brittle! Never got that result before! better replace ASAP in AM..."
What actually caused the noise I heard ( and felt thru my hand) was a solidified crust of rust and sediment (and who knows what else) at least 1/4" thick on the inside of the hose. When I squeezed the hose I broke the solid crust into chunks and pieces. (luckily I caught this before starting the engine again-fixed that issue, flushed system (almost 6 HOURS til it ran clear) replaced thermostat and crossed fingers, prayin'...)
But I'm not that kind of lucky. Overheating now. (on road trip-engine under load climbing hills). Pulled thermostat. Water pump is circulating coolant but flow seems a bit weak.
I'm pretty sure there's chunks of that rust rock blocking off coolant passages in the radiator or block or both.

HELP!! WHAT CAN I USE TO DISSOLVE THIS STUFF THAT WON'T EAT MY SEALS/ GASKETS/METAL?

or, alternatively, any constructive comments or suggestions would be most welcome!

 

You sure you're posting in the right forum?

 

well, uh, maybe.

No, my truck is not a Honda; however, my other two cars ARE Hondas and I've been coming to this site now for a couple of years because I know I can get well-informed advice and help here. (For which I will always be grateful.) I am aware that this is a Honda site....but can you blame me for staying with a proven formula?

The neglected cooling system problem referred to in my post could happen to almost any car on the road today.

I will remove the post if any find it inappropriate.

 

I would get some sort of high pressure water into the system from the top of the radiator, and try to force it out. I wouldn't trust any sort of chemical solution myself.

Good luck getting this thing back to proper condition!