Why water is coming out the tailpipe in a petrol car?

There can be a few reasons why water is coming out of the tailpipe of a petrol car. Condensation is the most common cause. Water vapor naturally forms when any engine burns fuel, and this vapor can condense into liquid water when it comes into contact with the cool surfaces inside the exhaust system. This is especially noticeable on cold or rainy days, or when the car is first started after sitting for a while.

Another possibility is that the car's head gasket is leaking. A blown head gasket can allow coolant to leak into the cylinders and be expelled through the exhaust. This can be a serious problem and should be checked by a mechanic as soon as possible.

Finally, it's also possible that the car's fuel system is flooded, causing excess fuel to be expelled through the exhaust. This can happen if the fuel injectors are leaking or if the fuel pressure regulator is faulty. Again, this is a problem that should be diagnosed and fixed by a qualified mechanic.