umm - dettol?....
its a bunch of some disinfectants, isopropanol, pine oil, soap etc.. You need an acid to cut that rusty scale off the metal bits. When a mechanic suggests you to use such items - do it first in a controlled fashion, e.g. find a rusty piece of metal and dip in in dettol+water.
It will be germ free for sure but the rust will be like the land mafia and wont move. You need big muscle to move the mafia (rust).
Be careful when derusting a system - I once derusted a system only to find 26 holes in the radiator, welch plugs, water pump etc of a cultus.
The mechanic RA actually said to the owner that pouring the water from a certain well near his shop was the best coolant - this water was severely salty btw.