The sugar in the gas tank story is probably as old as driving is.

It goes something like this: because of envy, malice, or for pranking someone opens your gas tank and pours some sugar inside.

The next scene is that you’re happily driving when all of a sudden the car starts to stutter and eventually cut out.

You get out of the car, raise the hood, scratch your head in surprise and worry while the prankster drives along, happy that he/she got the best of you.

This is the cliche anyway. But what are the facts if someone puts sugar in your gas tank? Will all of this unfold in this presumed way?

If it does happen, then what should you do?

All of this and more will be explained in this article. Should you encounter problems like this, it might help.



The common belief of putting sugar in a gas tank is that, once sugar gets in contact with gas a gooey sludge-like substance will form.

During driving the substance will enter the fuel supply and intake causing a clog and eventual stopping of the engine.

Pretty clever a man would say: inexpensive, has a delayed reaction so the driver can’t pinpoint the perpetrator and will certainly leave the poor driver on the side of the road.

This all seems like a pretty good scheme until reality kicks in.

You see, sugar will simply not dissolve in gasoline nor will the gooey like substance form.


As you can see in this illustration, sugar has been added to a glass of gasoline and left outside. After a couple of hours, the gasoline evaporated and the sugar was left almost intact.

No gooey substance at all. It only dissolved a little bit.

A similar situation would be in the gas tank. All that would happen is that the sugar would fall to the bottom of the gas tank and stay there, much like any other filth.

But this doesn’t mean that there wouldn’t be any problems.

The main danger lurks if the fuel in the gas tank was to be stirred up (like when driving on a bumpy country road for instance).

The sugar which has settled down then may raise up and get into the fuel filter and fuel lines.

It would take some time for the problems to start mostly depending on the amount of sugar inside the tank.

If there was enough, it could clog the sock filter on the fuel pump, main fuel filter, or cause a clog in the fuel lines.

To conclude on this part: if someone was to put sugar in a gas tank probably nothing would happen immediately. Especially if the car wasn’t driven for some time so the sugar can fall to the bottom of the tank.

Problems would start when the gas level gets low or if the fuel inside the tank was stirred up for some reason.

Then the sugar would be sucked in together with the fuel causing clogs in the filters or even engine problems if it was to reach it.



For the sake of this article, we’ll say that someone, somehow managed to pour sugar in the gas tank without you noticing absolutely nothing.

I must mention that this is nearly impossible because of things like:

  • The gas tank cap or cap door is locked, either with a key, locking mechanism or even protected with a car alarm
  • A lot of parking lots are covered with cameras or are inaccessible (they have guards, ramps or else)
  • Even if the car is parked on the street, the perpetrator will need at least a couple of minutes to open the cap door, take off the filler cap, take some sugar and pour it in. Today everybody has a camera and the chance that no one will take a picture or video is slim. Not to mention post it on social media (which has become almost necessary).
  • Trying to pour sugar in the gas tank in front of someone’s driveway is sheer stupidity as you’ll be seen in a matter of minutes because of cameras, people in the household, or the neighbors.

These factors can only lead to the conclusion that the idea of putting sugar in the gas tank derives from past times. On older cars, the gas tank cap was easily accessible. In modern times, it seems just downright foolish to try.

But, again, let’s disregard all of this and say that the perpetrator has managed to circumvent all of this and succeed at getting sugar in the gas tank.

What will the symptoms be:

  • Loss of engine power; since the fuel supply would be eventually blocked, fuel wouldn’t be able to reach the engine. You’d first feel it on the accelerator pedal as the car would start to bog down during driving. Probably rough idling would also occur.
  • The car would start to stutter and unusual engine sounds would appear. Even a misfire wouldn’t be unusual. These symptoms would barely be noticeable at first but towards the end, the car would be undrivable.
  • The final phase would be that the engine would completely cut off and you wouldn’t be able to start it at all.

Again, it would take some time for the symptoms to appear until sugar reaches the fuel intake.




Sorry to say, but if all of this happens, fixing it can be a very timely and expensive procedure.

This mostly depends on how long you’ve driven the car in this condition and the car model you drive.

The sooner you notice and stop the car, the less damage there will be.

As with any other kind of debris in the gas tank, there is a certain procedure that has to be done to get the fuel supply in order again.

If you have no experience around cars, best leave this job to a good and trustworthy mechanic.

However, if you want to do a DIY job the most important thing to know is that your working around highly flammable fuel.

Take every safety precaution needed. Don’t use open flames, prepare containers for the contaminated fuel, don’t use any power tools, etc.

Even if you’re not making the repair take a look at the whole procedure. It may give you an idea of what lays ahead of you in terms of time and repair costs.

The basic procedure is:

  1. Empty the gas tank completely or as much as possible. Best use a manual or electrical pump to empty it via the filler pipe. This is probably the best and safest way to do it.
  2. Take off the gas tank (disconnect fuel lines, electric connections and release the gas tank holders)
  3. Open the gas tank. Most tanks have an opening for the fuel pump and fuel gauge sender on top of it. This can be taken off giving you an accessing point for washing the gas tank.
  4. Thoroughly wash the gas tank, best with water, and some non-flammable cleaning solvent. Once washed, let the tank dry out completely and then check for any leftover sugar residue.
  5. Replace all of the fuel filters (namely the main fuel filter). Don’t forget the sock filter located on the fuel pump and fuel gauge housing (if this is the type on your car).
  6. If sugar managed to get into the fuel lines, disconnect them from the engine. Best use compressed air and blow out any residue in the lines. Make sure that they are 100% clear.
  7. Reconnect the fuel lines to the engine.
  8. Return the gas tank in place. Reconnect the fuel lines, electrical connections, and tighten the holders.
  9. Fill up with some new clean gas.
  10. Start the car and check for any leaks or gasoline smells.

As you can see, the procedure is pretty complicated. Additionally, on some cars taking off the gas tank is pretty hard as it demands dismantling other parts of the undercarriage to get it out.

If you’re interested, you can read more about gas tanks on Wikipedia by clicking here.

This procedure alone and the expense around it should make putting sugar in a gas tank plausible for a lawsuit.




Well, you’ve seen the basic procedure and that it’s pretty complicated.

The price I’m going to state highly depends on your car model, prices of labor in your country, prices of parts, accessibility for the repair, and other important factors.

The average price would be around 200 Euros, parts + labor. It can be less but for more complicated cars much higher.



If putting sugar in a gas tank is meant as a prank, there’s nothing funny about it.

When meant as an act of jealousy or malice, it should be treated as a crime and the perpetrator should be found and seriously punished.

It always reminded me of one of those ill-witted pranks where someone slips a foot between your legs, you fall and get hurt, sometimes seriously.

Then there is the question of safety: as mentioned, a car with clogged fuel lines will loose power, stutter, or even cut off completely. Imagine this happening in the middle of an overtaking or with a car full of passengers.

All of these important facts should prevent anyone from the idea of putting sugar into the gas tank.


Written by: Sibin Spasojevic


Former car technician, life-long car and DIY enthusiast, author for