Water in the fuel tank? Here is what and what not to do!

So recently there was an incident where a petrol station in Sahiwal filled people’s cars with water instead of petrol. Apparently, they had water in their underground fuel tanks for whatever reason and people got their new Civics and Suzukis filled with water instead of petrol for literally thousands of rupees. A gentleman at the scene mentioned that he got his car filled for Rs11,699. Petrol price is already at an eye watering level; you don’t need more water. Think about getting water for Rs235 per litre.

Govt. drops petrol bomb on people in the middle of the night

On one side we have people like that elderly gentleman in Karachi who paid for the fuel of literally hundreds of motorcyclists and rickshaw drivers, and on the other hand we have these people who would fill people’s cars with water instead of fuel. Anyways, so that was the news part of the blog. But what should you do in case you end up in such a situation? Let’s find out.

There are some do’s and don’ts that you need to follow once you find out that you have water in a vehicle’s fuel tank. Let’s start with don’ts first.

Do not keep cranking your engine in hopes that it will start with whatever fuel you had in your car’s fuel tank mixed with water. It is not going to work. In fact you are seriously going to damage the internals of your engine.

One thing that some might know is that water is heavier than petrol. Like one litre of water is heavier than one litre of petrol. So when there is water in the fuel tank, the water is going to sit in the bottom while petrol floats above it. And the fuel pump in the fuel tank is positioned in a way to get the fuel from the deepest parts of the fuel tank. And since water is heavier and sitting down below, the fuel pump will only be pumping water through the fuel system into the engine.

So when you keep cranking the engine with your fuel pump spraying water in the engine, you will keep filling the cylinder with water. And although it is pretty obvious but in case you are forgetting, water does not ignite like gasoline. And it also does not compress like air does in the combustion chamber. So you basically has something in the cylinder that neither is going to compress like air not burn like petrol, and that means your pistons, valves, and rings are going to be in deep trouble That means unnecessary load on the internal components of the engine and something will either bend, or break. And there is also the fact that you have now water in your engine’s combustion chamber that you will need to evacuate even when you have sorted the water in fuel tank situation. 

Also, some people try to drain the water filled tanks by removing the fuel line from the fuel rail while the fuel pump is pumping water out with the ignition switch at ON position. That is also not the ideal solution so also try avoiding that. Water can easily damage the electric motor and other components in the fuel pump which isn’t exactly made to pump water. And even if the fuel pump doesn’t fail, you will also have water residue in the lines and rails even after all the water is cleared and you will have to waste more fuel in order to clear the lines by keeping the pump running like you did for extracting water. And that means more wastage. 

Now let’s talk about the do’s. I’ll keep this brief so there is no confusion. Stop the car if it is already not stranded at the side of the road. Call a mechanic or better a towing service and take your vehicle to a trusted garage. The mechanic now has two options to remove the water from the tank. The more thorough one and also more time consuming one is to take the fuel tank off the vehicle, and pour the water out of the tank from where the fuel pump is mounted in. Taking the tank off and putting it back will of course take more time.

Steps you can take to cut down your fuel expenses!

Second option is to remove the fuel pump from the tank, and then either manually or with the help of some small water pump, like the ones found in water coolers, start pumping the water out from the tank without removing it from the vehicle. For that you will need some motor or some other system to remove the water since the opening gap in the tank where the fuel pump is put in isn’t big enough.

Car fuel tank view from underneath
Car fuel tank view from above with fuel pump housing showing from top

Once the water mixed fuel is removed from the tank, if it’s day time, put the tank in the sunlight for a few hours and let the remaining water evaporate. Or you can use compressed air and make sure you get inside the tank as much as possible. It might not be possible to completely dry out the tank but it’s better than not doing it at all.

Put the tank back on, put the fuel pump back in, fill the tank with fresh petrol, run the fuel pump and make sure its priming, run the petrol through the fuel lines and fuel rail for a couple of minutes, put all the lines back on, cross your fingers and give the ignition switch a few turns and hope it starts.

Fuel pump motor

This is a basic rundown of what you will need to do in case you are unfortunate enough to end up being in such a situation. Hope you learned something new today, until next time, keep an eye on the fuel station attendant.

Have you ever faced such situation in your life? What are your roadside hacks and how would you solve it. Let us know in the comments section below.

Leave a Reply