Start with the vehicle label, then read the station. Fuel labels abroad become manageable when you record the engine fuel, blend marker and grade at handover instead of trying to remember a country ranking. Petrol, gasoline, benzin and gasolina can describe the same broad fuel family, while a number such as 95 or a marker such as E10 adds information that the local word does not.
Use the choosing a rental car guide to record the assigned vehicle and return policy. The toll roads guide helps separate fuel charges from road charges, and the breakdown guide covers recovery evidence if a stop becomes an incident.
Read the vehicle before the pump
Write down the fuel instruction at handover
Ask the rental agent to say the fuel type and show the label beside the filler flap or in the manual. Photograph that label, the fuel gauge, dashboard and return requirement. Record petrol or diesel, minimum octane, E5/E10 or B7/B10 marker, and any separate AdBlue filler. Fleets can contain petrol, diesel, hybrid and bi-fuel versions of a similar car.
Keep a handover note in the local language
Write a short note such as “petrol, E10 permitted, 95 RON” or “diesel, B7, AdBlue separate” in the phone and on paper. If another driver takes the wheel, show the note before the first fuel stop. The fuel-door label is more reliable than a translation app or a colour remembered from the previous country.
Photograph the fuel gauge and filler label before leaving the branch. Photo by AbdAllah Khankan via Wikimedia Commons, CC BY 4.0.
Understand the standard label shapes
Treat E and B as blend markers
The European Union introduced common identifiers that are also used in UK guidance: a circle with E5 or E10 identifies petrol with up to 5% or 10% ethanol; a square with B7 or another B number identifies diesel with the stated maximum biodiesel share. Gaseous fuels use a diamond identifier such as LPG, CNG or H2. The identifier belongs on the dispenser, nozzle, vehicle and manual in the systems covered by the rules.
Check the marker against the vehicle
An E number is not an octane number, and a B number is not a guarantee that every diesel engine accepts the blend. GOV.UK says standard 95-octane petrol in Great Britain is E10 and points drivers to a vehicle checker; older vehicles and some equipment may require E5. Use the manufacturer instruction for B7, B10, XTL or any higher blend. If the marker is missing or unclear, pause and ask the station staff.
A dispenser label is more useful than a remembered hose colour. Photo by Tiia Monto via Wikimedia Commons, CC BY-SA 4.0.
Translate names without trusting colour
Use words as clues, not as the final check
Common petrol words include petrol, gasoline, benzin, gasolina, essence and benzina. Diesel may appear as diesel, gazole, gasóleo, gasolio, gasöl, gasoil or Japan’s 軽油. These examples help recognise a sign, but do not tell you the required grade. In France, “sans plomb” signals unleaded petrol; in Spain, “sin plomo” has the same role. Keep the number and blend marker in view.
Ask before lifting the nozzle
At a full-service station, say “petrol” or “diesel” and show the filler label. At a self-service station, read the words on the nozzle and the dispenser, then match them to the note in the car. Green, black or yellow handles are not a global code. A larger diesel nozzle can make one mistake harder, but it is not a safety system to rely on.
Confirm the fuel label before touching the trigger. Illustration by gnokii via Wikimedia Commons, CC0 1.0.
Match octane, blend and engine
Separate the number systems
Octane describes resistance to knock in spark-ignition petrol engines. Europe and many other markets display RON, while U.S. pumps use the anti-knock index, calculated from RON and MON. The numbers are therefore not a direct country-to-country conversion. The U.S. Federal Trade Commission requires the rating to appear on gasoline dispensers; “regular” or “premium” alone is not a technical specification.
Follow the minimum in the manual
Use the fuel-door label or manual to choose the minimum octane and the approved ethanol blend. A higher octane may cost more without helping a car designed for a lower grade. A lower grade can cause knocking or poor running in an engine that requires more resistance. Do not copy a 95, 98, 91 or 93 number from another market without checking how that market measures it.
Keep gas fuels and AdBlue separate
Treat LPG and CNG as different vehicle systems
LPG, also called Autogas or GPL, is a liquefied propane and butane fuel. CNG is compressed natural gas. Each needs a compatible tank, filler, nozzle and vehicle approval. The European label scheme uses separate diamond symbols, which helps distinguish them from petrol and diesel. A bi-fuel rental may start on petrol and switch to gas, but the company must explain which tank to fill and how the return policy works.
Never improvise a gas connection
Do not use an adapter, transfer fuel from a bottle or fill a tank that the rental contract does not authorise. Ask about station access, payment, shut-off steps and the location of the petrol reserve. If the car is not explicitly marked for LPG or CNG, use the ordinary fuel specified at handover.
An LPG filler is a separate system with its own connector. Photo by Parrot of Doom via Wikimedia Commons, CC BY-SA 3.0.
Treat AdBlue as an emissions fluid
Some diesel vehicles have a second filler for AdBlue or urea solution. It is often blue and may sit beside the diesel cap. AdBlue is not a fuel. If it enters the diesel tank, or diesel enters the AdBlue tank, do not switch on the ignition. Call the rental company and professional recovery; the AA warns that the fluid can damage pumps and injection equipment and may need workshop handling.
Act immediately after a misfuel
Before the engine or ignition is switched on
Leave the engine off and do not turn the key or press the start button. Tell the forecourt staff, pay for any fuel already dispensed, and ask for help moving the car to a safe position in neutral. Do not push a vehicle into traffic or try to drain the tank yourself. Contact the rental company and a recovery provider that can drain and dispose of contaminated fuel safely.
After the engine has run
Stop as soon as it is safe, switch off, and request recovery. Note the fuel selected, approximate quantity, distance driven, warning lights and symptoms. Keep the receipt and photograph the pump label. The longer contaminated fuel circulates, the more systems may be affected; the rental company needs the facts before authorising a repair or replacement vehicle.
Pay and return at an unfamiliar station
Prepare for the payment sequence
Some pumps authorise a card before fuelling, some require payment inside first, and some rural or unattended sites accept cash or a chip-and-PIN card only. A pre-authorisation can temporarily reduce the available limit. If a postal code is requested and a foreign card fails, pay inside. Keep local currency for a remote stop.
Match the return level with evidence
Read the rental contract’s fuel policy: “full” can mean the same gauge position as pickup, a specified number of bars, or a documented litre amount. Photograph the gauge, receipt, odometer and return bay. Keep the receipt until the deposit and any delayed fuel charge have settled. Never assume a cheaper station is permitted if the contract specifies a particular fuel or return procedure.
Fuel stop worksheet
- ☐ Fuel type, minimum grade, blend marker and AdBlue status are written on the handover note.
- ☐ The filler label and manual have been photographed before the first leg.
- ☐ Local words, the E/B or gas identifier, and the pump grade match the note.
- ☐ Colour is treated as a visual hint, never as the deciding check.
- ☐ Payment method, pre-authorisation, cash fallback and opening hours are known.
- ☐ A misfuel plan says: engine off, ignition off, safe position, rental company, professional recovery.
- ☐ The return fuel level, receipt, odometer and bay will be photographed.
Sources and review date
This guide was reviewed on August 17, 2026. Fuel names, blend availability, vehicle compatibility, station payment systems and rental policies vary by vehicle and jurisdiction. Recheck the fuel-door label, manual, station identifier, rental contract and recovery contact at the time of travel.
- GOV.UK: regulations for alternative fuel labelling
- GOV.UK: E10 petrol explained
- GOV.UK: E10 vehicle checker
- EUR-Lex: fuel quality and E5/E10 or B7 marking
- Federal Trade Commission: complying with the fuel rating rule
- The AA: what to do after putting in the wrong fuel