5 Most Common Misfuel Mistakes (And How to Avoid Them)

It Happens More Often Than You Think

Putting the wrong fuel in your vehicle isn't a rare, once-in-a-lifetime event. In the United States alone, an estimated 150,000 drivers misfuel every year. In New Zealand, thousands of drivers make the same mistake annually. It's one of the most common roadside emergencies — and one of the most preventable.

After years of responding to misfuel calls around the clock, we've identified five scenarios that account for the vast majority of incidents. Understanding these patterns is the best defense against making the same mistake yourself.

Mistake #1: Driving an Unfamiliar Rental Car

Rental car misfuels are far and away the most common scenario we encounter. The reasons are straightforward: you're driving a vehicle you've never fueled before, you may be in an unfamiliar area, and you're often tired from travel.

Many rental companies now include diesel vehicles in their fleets — particularly SUVs and trucks. If you normally drive a gasoline (petrol) vehicle at home, your muscle memory takes over at the pump. You grab the green nozzle without thinking, because that's what you always do. The problem? In some regions, green handles designate diesel, not gasoline.

How to Avoid It

• Check the fuel type before leaving the rental lot. Look at the fuel door, the key fob tag, or the rental agreement.
• Take a photo of the fuel type label inside the fuel door so you have a reference at the pump.
• Don't assume nozzle colors are universal. Color coding varies by region, station brand, and country.
• Ask the rental agent at pickup if you're not sure what fuel the vehicle requires.

Mistake #2: Distracted Fueling

We live in a world of constant distraction, and the fuel pump is no exception. Checking your phone, talking to passengers, managing kids in the backseat, or simply being lost in thought — any of these can cause you to grab the wrong nozzle without a second glance.

Misfueling is a habitual error. Your brain runs on autopilot at the pump because you've done it hundreds of times before. When your conscious attention is elsewhere, your hands do what they've always done — which is grab the nozzle you're accustomed to, regardless of what vehicle you're driving.

How to Avoid It

• Make fueling a phone-free activity. Leave your phone in the car or pocket while you're at the pump.
• Read the nozzle label before you lift it. Take one deliberate second to confirm the fuel type.
• Create a verbal habit: Say the fuel type out loud as you select the nozzle. It sounds silly, but it engages your conscious mind.

Mistake #3: Confusing Nozzle Colors and Pump Layout

Fuel station design is shockingly inconsistent. There is no universal standard for nozzle colors, pump arrangement, or labeling across fuel brands or countries. Green might mean diesel at one station and unleaded at another. Some stations put diesel and gasoline on the same pump; others separate them entirely.

In the United States, green nozzles typically indicate diesel — but this isn't mandated by law and exceptions exist. In New Zealand and Australia, the color conventions differ. In the UK, black typically indicates diesel. This inconsistency is a recipe for mistakes, especially for travelers.

How to Avoid It

• Ignore colors entirely. Read the actual label on the nozzle and the pump screen.
• Check the octane/fuel type display on the pump before you begin fueling.
• When in doubt, ask. Station attendants deal with this question regularly and would rather help you get it right than deal with a misfuel cleanup.

Mistake #4: Selecting the Wrong Pump Button

Modern multi-fuel pumps often require you to select your fuel type on a touchscreen or button panel before dispensing. It's entirely possible to correctly identify that you need diesel, walk to the right pump, pick up the right nozzle — and then accidentally press the "Regular Unleaded" button on the screen because it's the first option or the one highlighted by default.

This is particularly common at high-volume stations with large pump interfaces where multiple fuel grades and types are displayed. Under time pressure or in a hurry, it's easy to tap the wrong selection.

How to Avoid It

• Verify your selection on the pump display before squeezing the handle.
• Watch the price per gallon/liter. Diesel and gasoline are priced differently — if the price doesn't match what you expect, stop and double-check.
• Dispense a small amount first and check the pump display to confirm the correct fuel type is flowing.

Mistake #5: Having Someone Else Fill Up for You

This scenario is more common than people realize. You ask a friend, partner, or family member to fuel up the car while you run inside to pay or use the restroom. They drive a gasoline car themselves and instinctively fill your diesel vehicle with gasoline — or vice versa.

Delegation at the pump is risky because the person filling up may not know your vehicle's fuel requirements, may not think to check, and is operating on their own refueling habits rather than yours.

How to Avoid It

• Always communicate the fuel type explicitly. Don't say "fill it up" — say "fill it with diesel" or "it takes regular unleaded."
• Add a label to your fuel door. A simple sticker reading "DIESEL ONLY" or "UNLEADED ONLY" serves as a failsafe for anyone fueling your vehicle.
• Consider a misfuel prevention device that physically blocks the wrong nozzle size from fitting into your filler neck.

Bonus: The Borrower's Misfuel

A close cousin of mistake #5 is when someone borrows your vehicle — a friend, family member, or colleague — and misfuels it. They may not know or remember what fuel it takes, and social awkwardness can prevent them from asking. If you regularly lend your vehicle, a clear label on the fuel door is a simple and effective safeguard.

What If It's Already Happened?

If you're reading this because you've already put the wrong fuel in your car, don't panic — but do act fast. The most important thing is to not start the engine (or turn it off immediately if it's running). Then call a professional misfuel recovery service like EEK Mechanical. We operate 24/7 and can have a certified operator on site quickly to drain the contaminated fuel and get you safely back on the road.

Prevention is always better than cure, but when prevention fails, fast professional response is the next best thing.