I am flushing the radiator separately with citric acid...since3 days now and still white flakes of debris are coming off. I think I flushed 20 times by now. Unbelievable how much deposit this radiator has. I don't car as long as I get it all out.
After the radiator is clean I'll do the whole system with citric acid again. I guess if the radiator is that clogged the rest of the system might be too?
I'll do the system flush with acid probably before I'll change the thermostat?

After the thermostat maybe some flush with water and more water before I' put the fresh Toyota coolant in.