* Hydrolock: This is the most serious and immediate consequence. Water is incompressible, unlike gasoline. If the water gets into the cylinders, the piston cannot compress it, leading to bent connecting rods, cracked piston(s), or even a blown engine block. This is particularly likely if the engine is started while the water is present in significant amounts.
* Corrosion: Water promotes rust and corrosion throughout the fuel system. This includes the fuel tank, fuel lines, fuel pump, injectors (or carburetor), and even the engine's internal components. This damage might not be immediately apparent but will lead to long-term problems and costly repairs.
* Fuel Pump Failure: Water is much denser than gasoline and can damage the fuel pump. The pump might struggle to draw the mixture or even seize completely due to lack of lubrication and potential corrosion.
* Clogged Fuel Injectors/Carburetor: Water can clog fuel injectors or the carburetor jets, preventing proper fuel delivery to the engine. This can lead to a rough running engine, misfires, poor performance, and difficulty starting.
* Sensor Damage: Water can damage various sensors in the fuel system, leading to inaccurate readings and potentially causing the car's computer to mismanage the engine's operation.
* Catalyst Converter Damage: Water in the fuel can damage the catalytic converter as it introduces unburned fuel and oxygen into the exhaust system. This can lead to overheating and failure of the catalytic converter, a very expensive part to replace.
In short, finding water in your gas tank is a serious issue requiring immediate attention. Do not attempt to start the engine. Instead, have the car towed to a mechanic to have the fuel tank drained, the fuel system flushed, and the engine thoroughly inspected for damage. The cost of repair could range from relatively minor (fuel system cleaning) to extremely expensive (engine replacement), depending on the extent of the damage.
