Is acid (like 6% from vinegar or citric acid) a safe option for radiator and engine?
Can acid dissolve the debris inside the radiator adn wash it out.

I have now vinegar in the radiator only and leave it in over night. The first hours after pouring a gallon into the radiator hardly any of the whitish deposits was gone..the clear vinegar got a bit milky in color though. I'll see what happens tomorrow.

One question. .would a basic/alkaline solution be better for getting the debris out?

Martin