Gas in Diesel Engine Symptoms (Explained!)

Recently, I put gasoline in my diesel car. Why would I do this? Don’t worry, you’re not the only one. Mistakes like this happen when people are transferring fuel from one vehicle to another (usually when someone is borrowing your car).

It seems like everyone has the gas right by the diesel pump at their local station these days, which is tempting to always just use that pump. Unfortunately gas in a diesel engine will have some negative effects on it since the motor is built for thick diesel, not gas. In this article, we are going to look at some of the symptoms of putting gas in a diesel engine.

Gas in Diesel Engine Symptoms

Ignition Failure:

One of the most noticeable signs of gasoline in the diesel tank will be that your car won’t start. This can happen because the diesel fuel is too thin and will not provide enough power to ignite. The spark plugs won’t fire, causing a misfire and therefore, no combustion.


since there wasn’t enough ignition to create a burn, there will be black smoke coming out of the exhaust pipe instead of thick white smoke. If a car has a pre-cat system it will use the oxygen sensor to tell if it has enough fuel or not. If there is too much oxygen in the exhaust, the pre-cat system will activate and start shutting off cylinders, one at a time.

Car stuttering:

As the car runs, it will sometimes hesitate. This is caused by the constant shutting down of cylinders. For example, if you are driving on a highway at a high speed and suddenly slow down, the car will hesitate before accelerating.

Smoking exhausts:

The smoke coming out of the exhaust pipes will be black and oily. This is caused by the oil burning in the combustion chamber that results from too thin of a fuel. These burn marks can mess up your catalytic converter and can cause expensive repairs on your cars’ emissions system.

Performance loss:

The lack of spark means that the engine will not go as fast and the engine may hesitate while accelerating. If the vehicle motor is strong enough to start and move, you will experience low power and acceleration leading to engine failure

Check engine light on:

Another symptom of putting gas in a diesel engine is the check engine light coming on. This usually happens when the spark plugs are fouled from the fuel. You will notice as soon as you switch on your vehicle a check engine light comes on.

Engine overheating:

The engine will overheat while running. This is usually because of the diesel motor failing to handle gasoline as a fuel source.

Will Gas Ruin a Diesel Engine?

Gas in a diesel engine can cause a lot of damage and will require repairs to fix. The problem is that when you put gas in a diesel engine, it damages all the fuel systems on your vehicle. Gasoline is too thin for a diesel engine and has thinner lubricating properties as well. You will have to take your car into the shop so they can flush all of the lines so you won’t be getting any more black smoke from your engine.

How much does it cost to repair a diesel engine with gas?

After fixing a problem with a car’s fuel system, it could cost $600-1100 to fix a diesel engine with gas. However, if you want to prevent these problems from happening in the first place ensure that you put diesel in your engine.

Gasoline in a diesel engine causes all kinds of damage to your cars’ fuel system. If you switch over to diesel and use a pump at the gas station, you are putting your car at risk for more problems due to other factors.

Gas in a diesel engine should be avoided at all costs. Gasoline in a diesel engine must be dealt with quickly as the damage is permanent and can cause a lot of problems. The best way to prevent these problems is to not put gas into your diesel tank at all.

You should never fill up your car with gasoline unless you are sure it has been changed out for diesel fuel. If you want to make sure that your vehicle can handle fuel stops, make sure that you check the owner’s manual before parking your car by hand.


Gas in a diesel engine is dangerous and will cause a lot of damage to your car. You should always make sure that you put gas into your car’s tank so that it can get enough power and fuel to run properly.