Gasóleo vs Gasolina: Fuelling a Rental Car in Portugal

The two words that matter

Portuguese fuel stations label pumps in Portuguese. The only two words you strictly need:

• Gasóleo — diesel. Sometimes shown as “Gasóleo simples,” “Gasóleo especial,” or a branded premium diesel.
• Gasolina — petrol. Usually “Gasolina 95” and “Gasolina 98,” with 95 the standard grade.

The trap for English speakers is that “gasolina” looks and sounds like “gasoline,” so a diesel car can be misfuelled by reflex. If your car is diesel, the word you want is the one that looks less familiar: gasóleo.

How to know which your car takes

• Look inside the fuel filler flap — many cars have a “Diesel only” / “Gasóleo” sticker there.
• Check the key fob tag or the rental paperwork; some companies write the fuel type on it.
• Ask at the desk when you collect the car and note the answer.
• A diesel filler neck is wider; a modern petrol car often has a smaller opening with a green ring.

At the fuel station

Most stations on motorways and in towns are self-service (“self” or “automática”). Pull up, note the pump number, and either pay at the pump by card or pay the cashier inside afterwards by quoting the pump number. Attended stations exist in rural areas and simply add a small service premium.

• Diesel nozzles/handles are commonly black; petrol 95 is commonly green.
• Colours are a hint, not a guarantee — always read the word on the pump.
• “Aditivado” or premium grades are fine to use but cost more; the standard grade is all a rental car needs.

Fuel policies and returning the car

• Full-to-full (most common and usually best value): you get a full tank and return it full. Keep the receipt from a station near the drop-off.
• Full-to-empty / pre-purchase: you pay for a tank up front and return it as empty as you dare, with no refund for what is left. Often poor value unless you will genuinely run it down.
• Some off-airport suppliers charge a refuelling or “service” fee on top — check the terms.

For a full-to-full rental, fill up within a few kilometres of the return location and keep the timestamped receipt in case of a dispute.

If you put in the wrong fuel

Do not start the engine. Starting it circulates the wrong fuel through the system and turns a drain-and-flush into a major repair. Leave the car where it is, call the rental company's assistance number on your paperwork, and tell them what happened. Misfuelling is usually treated as driver responsibility, so the cost is likely yours, but it is far smaller if the engine never ran.