I added a few gallons of vinegar to an older Honda car I bought, mixed it about 50/50 with distilled water.
Started the car up, let the engine warm up, and let it sit for a day.
Did the same procedure every day for a week.
It really cleaned the engine and radiator up, no damage.
I saw an 8 door Duelley F350 coming down Rt 50 in WV, I damn well know there is some turns on Rt 50 that truck would have had to made at least a 3 point turn, just to get thru the corners.
It was a very nicely done truck from what I saw.