How to tell if your rental car needs diesel or gas

1. Look for a sticker

One of the easiest ways to tell if your car runs on diesel or gas is to check for stickers. These are often found on the car key, dashboard or fuel gauge. If you can’t find it, try opening the fuel cap cover, as there may be a sticker on the inside of the cap. Messages on these stickers are usually very straightforward and will read something like ‘Unleaded Gas Only’ or ‘Diesel Only’. If you check all those places and still can’t find a sticker, don’t worry, there are other signs to look out for.

2. Check the model name

Some car model names can hint at the type of fuel a car uses. Many diesel cars have labels like 'D’, 'TDI’, 'HDi’, 'GTD’, 'dCi’, 'JTD’ or similar variations. For example, if your car is a Volkswagen Golf TDI, the ‘TDI’ in the model name indicates that the car has a Turbocharged Direct Injection diesel engine. You can usually find these labels on the back of the car near the trunk. Although the model name is a good indicator of the car’s engine type, try to avoid using this as the only way you determine fuel type.

3. Speak to the rental car company

When in doubt, reach out. The rental company will know all the fuel specifications of your car and will be able to tell you what kind of engine you have before you refuel. You can ask this when you pick the vehicle up or call the helpline.

4. Read the car’s documentation

You can find the car’s documentation in the glovebox or driver’s side door pocket. This will usually include specific information about your car’s fuel type.

5. Consider sounds, symbols and smoke

Rely on your senses. Modern diesel engines are relatively quiet, but many of them still produce a distinctive sound and provide stronger vibrations than gas engines. Diesel cars generally emit darker and thicker smoke than gas-powered vehicles, especially during acceleration. You can also check your car’s dashboard for icons indicating the fuel type, with some even displaying the words ‘diesel’ or ‘gas’ during ignition.

6. See if the fuel pump will fit

Another way to unlock the clues to the engine type is by checking the size of your vehicle’s fuel pump nozzle. Diesel nozzles are a bit thicker than gas. So, if you’re struggling to insert a diesel nozzle into the fuel tank, chances are, it’s a gas car. But, the reverse scenario, slipping a nozzle for gas into a diesel tank, is much easier. Plus it can cause damage to vital components such as the fuel pump because diesel is more highly lubricated than gas. So, keep this as a last resort.

7. What to do if things go wrong

First things first, don’t panic. If you realize you’ve misfueled your car, keep calm and safely park your vehicle out of the way. Reach out to the rental company for support so they can help you get back on track. While you wait for assistance, avoid starting your engine as that’ll make the fuel circulate and could cause damage.

8. Don’t confuse fuel policy with fuel type

The fuel policy for your rental car doesn’t relate to the vehicle’s fuel type. Instead, it details how to handle fuel costs during your rental period. This policy states whether you need to return the car with a full tank, pay for fuel upfront or opt for the ‘Fuel Included’ option.