How to tell if a gasoline station mixup is filling your car with diesel fuel [Video]

Jacqueline Rutkowski-Murgia learned the hard way that filling up your car isn’t always straightforward. During a Cape Cod road trip, she filled her Range Rover Evoque at the “Premium” gasoline pump, only to have diesel fuel pumped into her tank by mistake. Her SUV broke down, leaving her with a repair bill over $4,500.

Quick tips to avoid the same disaster:

• Don’t pump any colored liquid into a gasoline vehicle [It’s probably diesel].
• Don’t pump an especially smelly liquid into a diesel vehicle [It may be gasoline].

Double-check your pump

Most gasoline and diesel fuel mixups happen when drivers grab the wrong nozzle. Mark Mancini at Mental Floss explains that diesel nozzles are often bigger than gasoline nozzles and sometimes painted green to help avoid confusion. But he warns that color codes aren’t universal. “A few companies—like BP—use green-tipped pumps on their gas dispensers.” That’s why Mancini recommends, “Do yourself a favor and read the label” before pumping.

Look closely at the pump layout. Gasoline hoses often come in a cluster of three for multiple grades, while diesel usually has one nozzle. Read the signs, pause distractions, and make sure the nozzle matches your vehicle.

Gasoline vs diesel fuel: different looks

Gasoline is clear, almost like water. Diesel is thicker (more like an oil) and usually tinted yellow-green. Diesel may also come dyed red if it’s “off-road” fuel meant for farm/construction equipment.

If you see anything but clear liquid coming out of the gasoline/petroleum nozzle, stop immediately and warn an attendant of a possible diesel fuel mixup.

Gasoline vs diesel fuel: something smells funny

Gasoline has a sharp, strong smell because it evaporates quickly, making it highly flammable. Diesel is less volatile and has a heavier, oil-like odor. Luke Kaz describes gasoline’s scent as “similar to paint thinner,” while diesel smells more like heating oil/kerosene.

Diesel vehicle drivers: If the fuel’s odor doesn’t match what you expect—especially if it’s too strong—stop pumping and double-check the nozzle.

What happens if you pump the wrong fuel?

According to Mental Floss, gasoline engines can’t combust diesel, so the car shuts down as soon as the remaining gas burns off. Diesel must then be drained manually, which requires towing the car to a mechanic and flushing the fuel system—a process that can cost $500 to $1,000.

Diesel owners putting gasoline in their tank won’t fare much better. Gasoline’s lack of lubrication damages diesel fuel injectors, leading to costly repairs.

Better safe than sorry

Rutkowski-Murgia’s story shows that mistakes happen—even when drivers do everything right. Still, the best defense is paying attention to nozzle size, fuel color, and odor. As Mental Floss warns, don’t rely on nozzle colors alone. And as YouTuber Luke Kaz demonstrates, “Gasoline looks like water,” so anything thicker or tinted should set off alarms.

In the end, the real cost of mixing up gasoline and diesel fuel isn’t just the repair bill—it’s the headache that comes with being stranded. So stay alert at the pump, trust your senses, and save yourself thousands of dollars. You can see the difference between fuels in Kaz’s video, embedded below: