The article “Why you shouldn’t alter the coolant in your radiator when the engine gets hot” explains why. The coolant in the radiator is extremely hot as you drive your car or any other vehicle. The coolant contains water it and heats to an extreme temperature while driving. It is possible that boiling water will explode when you open or take off the radiator cap when it is hot. If it comes into contact with the skin or your hands then you may be seriously damaged. This is the way that high-pressure coolant systems function.
Make sure that your coolant hasn’t heating up, and also that you aren’t driving. High pressure coolant systems can get hot and heat up, making it dangerous to alter the coolant once you have finished driving. When the engine and the radiator are cool, remove your radiator’s cap and allow the coolant to be replenished. If you are not an expert in mechanical work then it’s best to get your local garage to add fluid or flush the radiator. They’ll have the equipment for the task on systems that use high pressure. iy1d3ym197.