bad hose, radiator leak, leaking into engine.
It depends on what is wrong with it. We need more info please.
The coolant is not circulating through the radiator. The thermostat may be stuck in the closed position or the belt that rotates the water pump may be loose. Could also be a bad water pump. Or, if it is very cold and you don't have enough antifreeze, the coolant may be frozen and not circulating.
The remains of the old coolant can cause the new coolant to fail. Using the wrong type of coolant can also damage the engine.
What's wrong with it? If it doesn't retract, then the retractors need to be replaced. But if it is cut or frayed, the belt needs to be replaced. If it doesn't latch, then part of the latch mechanism needs to be replaced or repaired.
The check engine light comes on to tell you that something is wrong and the computer knows what it is. Use an automotive code scanner to find out what's wrong. Fortunately you and the computer agree... something is wrong. It's just that the computer knows a lot more about what's likely to be the problem.
A bad injector can cause your engine to flood out and not start. The bad injector might be completely open and shooting too much fuel into the system.
Wrong mixture make sure you have pre diluted/mixed coolant/antifreeze.
Provided that the bottles are properly cleaned and filled with clean water AND provided the consumer is not misled into thinking it is the branded version, nothing is wrong.
No.
If only adding coolant to a leaking system it is safe because soon you will be forced to drain the coolant and fix a problem
A leak. You need to see where it is coming from.
you need to add coolant to the coolant resevoir. coolant is antifreeze. if you dont have enough in your car you can overheat and damage your engine.