5 Signs You Have Water in Your Gas Tank (And How to Fix It)
It’s clear that water in fuel is a serious problem. How do you know if someone has put water in your gas tank? How do you know if you received a tank with bad gasoline? Or maybe your diesel fuel has water in it? We’ll answer these questions (and a few more) in this article.
What happens if you get water in your gas tank? Gasoline and water don’t mix, so your car can’t run on water. Water in fuel can cause twitching and stuttering, among other things. The symptoms are always worst when accelerating (when more fuel is needed).
The 5 Most Common Symptoms of Water in the Gas Tank
The symptoms of water in the gas tank can be similar to other problems, so they may be overlooked. Typically, you’ll see these common signs of water in your gas tank:
1) Performance Issues
Your car may wobble or hesitate when accelerating. The harder you press the gas pedal, the more noticeable this becomes. The reason is that water in the fuel tricks sensors like the MAF into thinking a certain amount of fuel is entering the combustion chamber. In reality, only some of the liquid is actually fuel, the rest is water. This disrupts the air/fuel mixture, essentially creating a “lean running” condition.
2) Your car’s performance changes overnight
Literally. It will run perfectly today and tomorrow, but when you start filling it with water, it will stop running altogether. You may notice a difference when starting it up, but it’s most noticeable when driving or accelerating.
3) White smoke coming from the exhaust
When water gets into the combustion chamber or exhaust system, it naturally evaporates and creates steam. This will make you see a lot of white smoke coming out of the exhaust pipe. Do not confuse this with the light white smoke you may see when starting your car on a cold morning; it will be even more noticeable if there is water in the gasoline.
4) Hard to start (or won’t start at all)
Similar to acceleration, when starting your vehicle, your engine needs a rich air-fuel ratio, which means it needs more fuel. This means the water-fuel mixture will be more clearly visible.
If there is not enough fuel to ignite the spark plug, it may take several seconds for the ignition to complete. This will make your car very hard to start. There is a chance that your car will not start due to too much water in the fuel.
5) Check Engine Light
Like many other issues that rely on accurate sensor readings, the sensor in question (such as the mass airflow sensor, intake temperature sensor, oxygen sensor, etc.) will relay this information to your vehicle’s ECU.
If the ECU determines that the information coming from the sensor is incorrect, it will trigger the storage of a trouble code. This will turn on the Check Engine Light in the instrument cluster. Using an OBD2 scanner can help you see the problem and determine if it’s related to an incorrect fuel mixture.
How to Drain Water from a Gas Tank
You can find additives that will remove water from your fuel. Iso-Heet is probably the best water remover on the market today, but there are others. These products have some effectiveness. If you have more gasoline than water, they work pretty well. It won’t be effective otherwise.
For safety, we recommend draining the tank completely. If you have mechanical experience, we also provide step-by-step instructions, but for most people, the best option is to let a professional handle it.
Step 1 – Empty the Gas Tank
Take an afternoon and drain your gas tank completely. Gasoline is less dense than water, so it will stay on top. You need to drain the water first.
Some people recommend waiting until the fuel leaks out. We don’t do that. It might save you a few dollars, but the damage it could do to your car isn’t worth it. But if you do drain the fuel, leave it for a long time. You want to get as much water out as possible.
If your tank doesn’t have an emptying feature, you’ll have to do it the old fashioned way: you can remove the tank and empty it, or pump the gas out. Be careful; gasoline is flammable.
Step 2 – Replace the Fuel Filter
Get a new fuel filter and replace the old one. Water can damage the fuel filter, causing it to fail or become weak and ineffective. Plus dirt and debris can get into your engine and cause further problems.
Would you rather spend money on a new filter or overhaul your engine? Replacing the filter is the safer solution.
Step 3 – Flush the fuel lines
Flush the fuel lines. These are intended for piped gas, not water lines. If water gets in, the pipes will begin to corrode. This can cause small leaks that may be hard to notice, but will reduce fuel consumption and pose a real fire hazard. If you’re not sure how to do this properly, ask a mechanic for help. It’s quick and doesn’t cost the earth.
Step 4 – Fill the gas tank
Fill it up and you’re good to go. All you have to do is add new fuel and you’re good to go.
Avoid future problems
Unfortunately, there are some gas stations out there looking to make a quick buck. They get around this problem because it may go undetected for a while. It’s also hard to prove that a gas station is the culprit.
These gas stations may dilute the gasoline to save money or buy it from cheap or dishonest suppliers. If the price you paid for gas seems too high to be true, the gas may be contaminated.
It’s best to find a good gas station and stick with it. Be careful in unfamiliar places. Ask someone you trust for advice on where to get the best gas.
If your car doesn’t have a locking gas cap, consider adding one. There are people out there who have nothing better to do than sabotage your car. It doesn’t matter if they’re trying to trick you into money or are just malicious.
Does gasoline float on water? Yes it does. Liquids have different densities. Fuel rises and water sinks. The fuel system draws gas from the bottom, which means water gets drawn in first. That’s why you’re in trouble right away.
Should you drive your car in this condition? This question is also hard to answer. If you’re just taking a short trip, e.g. to your home or a repair shop, everything should be fine. But remember that a vehicle needs fuel to move on its own, so if water gets in instead, it won’t have enough energy to move.
To make matters worse, your fuel system isn’t designed to handle water; gasoline and oil lubricate the car’s internal workings. If water gets into the mix, it can cause rust in the pipes or more serious consequences like chafing.
These parts rub against each other as part of their standard function, but as long as the parts are properly lubricated, that’s fine. Water can upset the delicate balance.
Should you drive your car? No, you shouldn’t. While a trip to the mechanic may only require a short drive, you risk causing serious damage to your vehicle if you drive it until the entire system has been flushed.