Help! I Put Gasoline in my Diesel Car!

It happens more often than you might think. Accidentally using the gas pump instead of the diesel pump, and filling up with a full tank of gasoline before you even notice. So what now? Don’t worry, because if you follow the proper procedures you can get out of this situation as cheaply and easily as possible. 

Well, the first step you need to take is; do not turn on the engine. If the engine even manages to run at all, gasoline’s tendency to ignite easily can cause uncontrolled combustion within the engine and damage parts in the process.

How do Gasoline and Diesel Engines Differ?

It’s important to understand the difference. Both gasoline and diesel engines operate on the same principle, internal combustion within cylinders. The difference is that they go about it in different ways. Gasoline is a thin substance and uses a spark from a spark plug to detonate. Diesel on the other hand is thicker and requires high heat and pressure to detonate, rather than a spark.

Diesel also lubricates the fuel system, and the pump and injectors rely on those properties to continue functioning properly. 

What Happens When Gas is Put in a Diesel Engine?

As stated earlier, gas is volatile in a diesel engine and may combust uncontrollably if the engine even turns over at all. Diesel engines are not built to withstand the combustion of gasoline, and the internal engine parts can sustain major damage if gasoline is detonated within it. 

Along with this, gasoline also lacks the lubricative properties of diesel. This will damage the fuel system, including the pump and injectors, which can be an expensive repair. 

In a lot of cases, a complete engine rebuild or replacement is required when the vehicle is started. If you get lucky, it may “only” need substantial repairs.

So What Do I Do?

Just to reiterate again, avoid starting the vehicle at all costs. Call a tow truck to come to pick up your vehicle and have it dropped off at a shop you trust.

From there, the shop will drain the fuel from the system and check for damage throughout the engine, fuel pump, and injectors. If you have already started the vehicle, they most likely need to replace much of the fuel system.

It’s pricey to get your tank pumped, but it’s even worse to have to replace an engine and fuel pump. Ensure your vehicle is going to a trustworthy shop and you’ll get out of the situation with the best result possible. 

How do I Avoid Doing This in the Future?

The simplest answer is to ensure you’re using the right pump. Diesel pumps are often green, although not always, so check the label (BP gas stations are notorious for this). They also lack the octane numbers that are listed on gasoline pumps.

Pumps for gasoline will usually list a number between 87 and 93, these are octane numbers, which only apply to traditional gasoline. Diesel pumps will just list “Diesel” or “Diesel #2” the vast majority of the time. 

Some gas stations carry ethanol fuel, which will be listed with the numbers 15, 30, or 85. These pumps should also not ever be used in diesel vehicles. 

Fuel System and Engine Service at Borst Automotive

If you find yourself in this situation, don’t panic. Tow your car to a trusted shop and you’ll save a lot of money over trying to drive it.

The expert diesel technicians at Borst Automotive in Arizona are here to help. We have four locations; one in Phoenix, one in Mesa, and two in Tucson. We’ll ensure your diesel engine is safe to continue driving and that you get out of this situation for a fair price. 

Call or schedule an appointment today to meet with our friendly team and helpful service advisors!