First Time Driving a Diesel Rental Car in Vietnam

First time driving a diesel rental car—what matters most? Filling the correct fuel. Putting petrol in a diesel (or the reverse) is a common mistake for drivers used to petrol cars, and the right response is do not start the engine. Most of our self-drive cars are petrol, but if you receive a diesel SUV or pickup, use the notes below.

Staff briefing a customer at self-drive car handover — Illustrative photo

How to know which fuel the car uses

Ask at handover: staff will state petrol or diesel—note it on the handover form.
Look at the filler cap: many cars label the fuel type inside the cap.
Read the owner’s manual in the car: the specs section lists the fuel.
Dashboard: diesels often show a glow-plug light (coil icon).

Some 7-seat SUVs such as Toyota Fortuner or Ford Everest have diesel versions—do not guess from the model name; ask about the exact car you receive.

At the station: find the DO diesel nozzle

In Vietnam, diesel is sold as DO (often with a sulphur grade mark). Petrol is labelled RON 95 or E5 RON 92. Before filling, tell staff “DO diesel” and check the nozzle again. If you self-serve, read the pump label—do not rely only on hose colour.

If you fill the wrong fuel—follow this order

Do not start the engine; do not turn the key if you notice at the pump. Turning the key can run the fuel pump and push the mix through the system.
Tell station staff and push the car clear of the pump lane if needed.
Call the rental company at once for guidance and handling. Do not seek an outside mechanic on your own.
If you already drove and the car feels wrong (jerking, heavy smoke, stalling), pull over safely, switch off and call the rental company.

Liability and costs for wrong fuel are in the contract—read that section when you sign. The contract is detailed and signed by both sides.

Customer calling the rental company at a fuel station — Illustrative photo

How diesel driving differs from petrol

Situation	Diesel
Starting	Turn key, wait for glow-plug light to go out (if fitted), then crank
Engine sound	Louder and more “clatter”, especially when cold—that is normal
Acceleration	Strong pull at low rpm; no need for deep throttle
After long expressway runs	Idle briefly before switching off if the manual recommends it (turbo cars)
Unusual warning light	Stop safely and call the rental company—do not DIY

Before return

Refuel to the level noted on the handover form, with the correct DO diesel, and keep the fuel receipt. See also the self-drive expressway checklist and self-drive fleet pages. On self-drive, you pay fuel and road tolls yourself. Live with-driver alternative: /en/dat-xe.

Frequently asked questions

Are your self-drive cars mostly petrol or diesel?

Mostly petrol, because diesel maintenance costs more in Vietnam. VinFast EVs are also available for self-drive.

Is a little petrol in a diesel serious?

Do not judge yourself. Do not start the engine; call the rental company.

Is a loud diesel engine a fault?

No—diesels are noisier than petrol, especially when cold. If noise comes with a warning light, call the rental company.

How do DO diesel and E5 petrol differ?

DO is for diesel engines; E5 RON 92 and RON 95 are for petrol engines. Do not substitute one for the other.

Fuel station routine

Check the fuel cap label and say "dầu" for diesel at the pump. Keep the receipt.

If the wrong fuel goes in, do not start the engine; call the rental team.

See diesel maintenance and petrol or diesel.

Quick answers

Is diesel louder? Often a little at idle.

Does it need warm-up? Not usually in Vietnam’s climate.

If you are planning a nearby route, Planning a Mountain Drive in a Rental Car has more details to help you prepare.