MUDGUARDING COOLING WATER

friends, my car's cooling tank looks brown I can't even see the level of the water without opening the lid. How should I completely drain all the water, if I wash the water tank with the spirit of salt? Why it may be muddy, the vehicle has no movement problems and antifreeze in the water

Oil is mixed into the cooling water of your car. Your recipe indicates this. I recommend you to show it to your master to be sure.

There is no oil reduction and water reduction problem in the vehicle, there is no abnormality in the exhaust smoke. is there any other sign of this