What Happens If You Put Gas In A Diesel Engine?

Published on 01/31/2022

what happens if you put gas in a diesel engine

Have you ever wondered what happens if you put gas in a diesel engine? Many truckers and owners of diesel cars also own vehicles that run on gas. The risk of absent-mindedly stopping at the wrong pump and putting the wrong fuel in the tank is a real concern.

At All Bay Diesel, we’ve seen the effects of gasoline in a diesel engine many times, but don’t worry. We can help you know what to expect and what to do about it.

If you have damaged your diesel engine by using gasoline, you can learn more about our diesel engine repair service at All Bay Diesel.

Differences Between Diesel Engine And Gasoline Engines

Diesel and gasoline engines are both internal combustion engines. Like gasoline engines, diesel engines burn fuel that generates the force that moves your car. However, diesel engines burn fuel under high pressure. The pressure and temperature cause the diesel fuel to ignite without the spark from a spark plug. Gasoline is thinner and requires a spark for ignition. 

Diesel fuel acts as a lubricant as well as an energy source. Diesel engines rely on the ability of diesel fuel to lubricate the fuel injector and other parts of the fuel system.

These physical differences change the behavior of the fuel in the ignition chamber. 

What gasoline does to a diesel engine

A full tank of gasoline will do more damage than a few gallons of gasoline mixed with diesel fuel. A gasoline-diesel fuel mixture ignites more easily, which could cause ignition within the engine. An uncontrolled and mistimed detonation within the engine is like a small bomb going off. The diesel engine is not set up to handle it, and its parts will sustain damage.

The engine, if it runs at all, is likely to sputter. The gasoline will not ignite consistently because there is no spark plug, and the fuel will not burn correctly, causing black smoke to come from the exhaust. The fuel pump and fuel injectors fail due to gasoline’s inability to function as a lubricant.

The engine will eventually stop running entirely, requiring substantial repair or replacement. You will naturally want to do what you can to avoid this catastrophic scenario.

What to do about misfuelling?

The best thing to do if you add gasoline to a diesel engine is not to start it. Tow the car to a professional auto repair company to empty the diesel tank. If you have already started the engine, stop the engine immediately and tow the vehicle in to have the fuel drained from the system.

Damage to the fuel injector may be permanent. However, a professional mechanic can determine which parts of the engine can be saved and rebuild the engine.

Essentially, what happens if you put gas in a diesel engine is that you will need a new engine or at least a substantial engine repair.

How to prevent future misfuelling mishaps

Knowing the consequences of adding even a small amount of gasoline to a diesel engine, it is crucial to find ways to remind yourself which fuel to add when you are at the pump. The following tips will help you to avoid mistakes.

Get into the habit of checking the label on your fuel cap. It should say DIESEL ONLY. If it doesn’t, you can add a warning sticker.

Add a color-coded label to the fuel caps of your diesel and gasoline-burning car.

Color code your key rings to match the fuel caps. That will serve as a last-ditch reminder before you turn the key.

When you are at the pump, ask yourself how the pump stands and nozzles are different for diesel and gasoline pumps. Answering this question will focus your mind on the pumps to ensure you are at the right pump. Knowing the difference between the two nozzles will help you make one last check as you insert the pump, just before you start pumping fuel.

Getting the engine system fixed after misfuelling

Once you have gotten your car to the repair shop, the mechanic will drain and clean the tank, replace the filters, and inspect other components, such as the fuel injectors and the fuel pump. If you never start the car, more engine components might be spared damage.

Professional Engine Repair At All Bay Diesel

In the end, what happens if you put gas in a diesel engine is that you wind up at an auto repair shop. You need someone you can trust to rebuild your engine after a misfuelling. Experience can make the difference between spending thousands on a rebuilt engine and spending much less on a few replacement parts.

All Bay Diesel can repair, rebuild, and replace diesel engines. For professional diesel engine repair in Berkeley, call (925) 522-1780 for towing or to discuss what we can do for your diesel vehicle.

Call Now: (925) 522-1780