There’s nothing wrong with using water – well, actually mixed with ethylene- / propylene-glycol or antifreeze, to cool down an internal combustion engine, just as long as you know where to put it.
Pour it in the radiator of a liquid cooled car (when it’s not hot) and you’re good to go, but add it where there’s an oil symbol on top of your engine and, well, you can congratulate yourself for ruining your car – at least if you turn the engine on, otherwise, you might save the day by draining out the water.
A video posted on YouTube shows a car in which the owner purportedly filled the engine up with water instead of oil “because it was overheating“.
According to the mechanic who was draining the engine, it was “17 quarts overfilled [16 liters], 15 [14.2 liters] of which were water”.
Note: NSFW audio in the video