It works nicely.
The main points to remember : when engine hot, NEVER add cold water/coolant to reservoir or radiator.
Intense peak in temp change can cause cracks in engine casing or radiator.
Here is the procedure for perfect radiator flush :
1. when engine is cold, flush the entire coolant. Add water.
2. use car for few kilometers until engine gets hot and water pump of radiator is activated. keep the reservoir cap loose to remove air pockets and keep adding water as required.
3. drain the water.
4. If the water color changes to red or has different color than coolant,
repeat the same procedure "1,2,3,4,"several time until you get clean water on radiator flush.
5. (This flush is for 7ltr and most car has max 3-4 ltr of coolant ) Next add half bottle of radiator flush with water mixture to coolant reservoir. Use car for several days in city trafic (no long runs during this period)
6. flush the radiator and check color. It should be reddish containing burr and rust.
7. repeat 1,2,3,4.
8. Add second half of radiator flush and repeat step 4.
9. Once you ensure water doesn't change color after several radiator flushes. Congrats!! your coolant system is restored to showroom condition.
10. prefer good coolant concentrate with distilled water than ready-made coolant, and you are done.