Whitney Burch
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What to Do if You Accidentally Put Diesel Fuel in Your Car

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No matter how many times you’ve visited the gas station, chances are you’ve noticed that special nozzle and button usually placed at the end of the gas selector display marked “diesel.”

Sometimes it’s right next to the other gas selections like regular, mid-grade, and premium. Other gas stations have a separate gas pump just for diesel, so the only gas selection display you should see should look like this gasoline-only pump.

gas pump

Photo: osseous

Other times, the diesel button is located off to the side all by itself, like this one.

gas pump

Quite a helpful design to minimize the chance that a person accidentally puts diesel fuel in their car’s gasoline-only engine.
Photo: carlie b

But what if you accidentally put diesel fuel in your car? Say for instance, you are running on a total of six hours of sleep for the week and your mind is mush. Or you forgot to grab some much-needed coffee on your way to work to help disperse the clouds of brain fog. Or it’s late at night and you just happen to run out of gas before you head home and stop by an unfamiliar gas station and the gas pump buttons just look wonky.

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Here’s what to do if you put diesel in your vehicle

  1. If you fill up your tank with diesel and realize it right away, then don’t start your vehicle. Call for a tow and have a local mechanic flush out the fuel tank to prevent any permanent harm to your vehicle.
  2. If you put diesel fuel in your vehicle, turn on the engine, and maybe even drive it for a few miles before realizing your mistake, pull over as soon as you can and turn off the engine. Contact a mechanic for a tow and request a fuel tank flush.

How much you should expect to pay

Because personal vehicles have engines specifically designed for running on gasoline rather than diesel, filling up your engine with diesel can potentially ruin your car’s engine and result in costly repairs. Owners should be prepared to pay anywhere from $400 to $1,500, according to Tim Anderson, owner of Automotive Authority in Troy, Michigan, who is quite familiar with performing these kinds of repairs.

Exactly what type of havoc does diesel wreak on the average vehicle engine? Diesel fuel usually damages the piston or cylinder head. It can also create deposit build-up around valve closings. Both conditions result in a loss of compression. In the worst case scenario, you might have to replace your car’s entire engine which will set you back anywhere from $2,000 to $4,000.


But there is hope…

Long story short: do everything you can to avoid putting diesel in your vehicle. But, if you do, with the help of a skilled mechanic, there’s a chance you could save your engine.

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News Sources: Jalopnik, Car Care

  • Whitney BurchEditor

    Whitney Burch is a current resident of Dayton, though her spirit can be found beach-bumming on Puerto Rico (the land of her half-Puerto Rican heritage that she has been gifted to visit…and plans on visiting again sometime when the Future deems it practical!). When not adventuring through the exciting world of car news, she can be found hiking with her boyfriend and their growing-up-too-fast Labrador puppy, motorcycling, reorganizing and/or decorating some corner of the world (most likely in yellow), researching random things, scribbling on her blog, and escaping into a great movie, poem, or short story. See more articles by Whitney.

  • bshizle

    This article looks like an article that I have read before. The problem is that it is overly simplistic. Gasoline & diesel are both distillates of crude oil. They contain many different proponents of crude & the formulas are changed based on need of other distillates such as jet fuel or climactic conditions. In fact #1 diesel, which is a cold weather fuel, is really kerosene which has been used in spark ignition motors for a century now. They differ in a number of ways. While diesel relies on a cetane rating which allows it to easily burn while the fuel /air mixture is compressed without a spark or flame. Gas on the other hand has additives which require that a spark be delivered before it will burn even when it is in a mixture with available oxygen & compressed. In gasoline the more this mixture can be compressed the higher the octane rating & this high octane fuel would be undesirable in a diesel motor since it is a compression ignition engine. Diesel unlike gasoline is resistant to evaporation since it is an oil so it would not work well in a carbureted motor however most gas engines are now fuel injected.
    Diesel hose ends in the U.S. are bigger and don’t fit into any of the gas burners that I have owned & while this may not be universally true I find it hard to believe that in most cases that a person could do this without recognizing very quickly that there is a problem. I know this because I used to run diesel in my gas motors at a rate of 1 to 13 gallons. I did this because at the time diesel was cheaper & as is still the case produced more power per unit but I digress, the 1 gallon that I pumped in took almost 3 minutes. Also I didn’t have any issues with this though it was probably a waste of time.
    I agree that if one fills their tank up (from empty) on a gas burner with diesel the tank should be purged but there are degrees here. Some people fill up when they pass a certain place that they know is cheap, others fill up when price fall below a certain price or if they are going on a trip. Okay, what if it is a borowed vehicle & the tank that was accidently filled with diesel is in a diesel fueled car. Like I previously stated a person should know when they are pumping the wrong fuel so if there is only a few gallons in say a 20 gallon tank full of gasoline the obvious choice would be to run it out. Octane booster can be purchased at any parts store. Any good mechanic should tell you this & save you from wasting $1,500.00.