Quick answer: a Hummer H2 stretch limo was filled with diesel instead of petrol at the Liberty servo in Greenvale. It barely made it out of the driveway before it ran rough and was pulled back in. We drained the tank, flushed the fuel system and fitted new spark plugs. After about 85 minutes of cranking it fired, blew out a huge cloud of smoke as the diesel burnt off, and was running just in time for a booking that night. The price was our standard fixed $450 plus the cost of the plugs.
Some jobs take 45 minutes at the pump. This one took most of a Saturday afternoon. It is a good example of why we don’t give up on a vehicle just because it won’t fire on the first go, and why a misfuel in a big petrol V8 is still a roadside fix, not a trip to the workshop. If you have put diesel in a petrol car anywhere in Melbourne, the short version is: stop, don’t keep cranking it yourself, and call us on 1300 692 469.
The Job: A Stretch Hummer, a Tank of Diesel and an Evening Booking
The call came from Alex, a Melbourne limo operator, on Saturday 3 October 2026. One of his white Hummer H2 stretch limos had just been filled with diesel instead of petrol at the Liberty servo in Greenvale, in Melbourne’s northern suburbs. The driver started it and pulled out of the servo, realised straight away that something was wrong, and brought it back in. That was the right call. It meant the diesel had only just reached the engine, and the car was still sitting at the pump when we arrived.
For a limo business, the repair bill is only half of it. The Hummer was meant to be on a booking already, so Alex had to shuffle his fleet and send another car in its place. That left him a vehicle short for a second booking later that night. If the Hummer wasn’t running by the evening, he was going to be letting someone down. So the job had a deadline.
| Job detail | What we found |
|---|---|
| Vehicle | Hummer H2 stretch limousine, 6.0 litre petrol V8 |
| Problem | Diesel in the petrol tank, started and driven out of the servo |
| Location | Liberty servo, Greenvale, northern Melbourne |
| What we did | Drained the tank, flushed the fuel system, fitted new spark plugs, two attempts to start |
| Time to restart | About 85 minutes of cranking |
| Result | Running just in time for that night’s booking |
| Price | Standard fixed $450, plus the cost of the spark plugs |
Why Diesel Stops a Petrol V8
A petrol engine lights its fuel with a spark. Diesel is heavier and oilier and doesn’t ignite properly from a spark plug. Once the diesel reaches the engine, the plugs get wet and fouled with it, the engine misfires, smokes, loses power and eventually stalls. If the driver keeps cranking, more diesel is pushed through and the plugs get worse.
Starting and driving after a misfuel is what turns a simple drain into a longer job. Even a short drive out of the servo is enough for the fuel lines, the fuel rail and the plugs to end up holding diesel, not just the tank. We cover this in more detail in can you drive after putting wrong fuel in and how a started engine changes a wrong fuel rescue. A big vehicle like this also means a big tank, so there is more contaminated fuel to drain and take away.
How We Got It Running: Two Attempts and 85 Minutes of Cranking
We drained the contaminated fuel from the tank and flushed the lines, then filled it with fresh petrol. That gets clean fuel to the engine, but the cylinders and plugs were still soaked in diesel from when it was started and driven.
The first attempt didn’t get it going. Rather than call it and send the limo off on a tow truck, we went again. We pulled the old plugs, which were fouled with diesel, and fitted a new set. Then it was a matter of patience: cranking in short bursts, letting the starter rest, and working the leftover diesel out of the cylinders a little at a time. All up it took about 85 minutes of cranking before the V8 caught and held an idle.
Tip: don’t try this part yourself. Long cranking without resting the starter, or with diesel still in the tank, can damage the starter motor and the catalytic converters. Leave it switched off and let us do it in a controlled way.
The Smoke on Start-Up Was the Good News
When a petrol engine full of diesel finally fires, it smokes. A lot. The leftover diesel in the cylinders and exhaust burns off in a thick white-grey cloud, and with a V8 in a car this size it filled the forecourt. It looks dramatic, but it is exactly what you want to see. It means the engine is burning off the last of the diesel on clean petrol.
The smoke cleared as the engine warmed up, the idle settled, and the Hummer drove off the forecourt just in time to cover that night’s booking. Alex’s fleet was back to full strength.
What It Costs
Our prices are fixed and quoted on the phone, include GST and have no card fees. For Alex’s Hummer we charged our standard fixed $450, plus the cost of the new spark plugs. Nothing else was added for the extra time it took. Starting the engine or driving it doesn’t change the price, and it is no fix, no fee. Full details are in our 2026 Melbourne price guide.
| Vehicle | At the fuel pump | Roadside or at home |
|---|---|---|
| Most cars, utes, vans and 4WDs | $450 | $475 |
| Parts if needed (for example spark plugs) | At cost | At cost |
Commercial operators like limo, hire car and transport businesses can also set up an account with us. See our fleet and business wrong fuel service.
What to Do If It Happens to Your Vehicle
- Stop at the pump if you can. If you’re driving, pull over somewhere safe and switch off.
- Don’t keep cranking the engine to see if it will go.
- Don’t top up with the right fuel to dilute it. It’s still contaminated.
- Note how much fuel went in and call us on 1300 692 469.
Not sure which fuel your vehicle takes? This carsales guide to choosing the right fuel explains the main fuel types sold in Australia.
Frequently Asked Questions
What happens if you put diesel in a Hummer H2?
The H2 has a petrol V8, so diesel won’t ignite properly from its spark plugs. If it is only in the tank, a drain and flush fixes it. If the car has been started or driven, diesel reaches the engine and fouls the plugs, causing misfires, smoke and stalling. That needs a drain, flush and often new plugs, which we can do on site.
Why does the engine smoke so much after a diesel misfuel?
The smoke is leftover diesel burning off once the engine starts on fresh petrol. It looks dramatic, especially from a big V8, but it clears as the engine warms up and is a sign the job is working.
Can you fix wrong fuel in a limo or other large vehicle on the spot?
Yes. We drain, flush and restart large vehicles at the servo, at your depot or at the roadside. Limos, 4WDs, vans and trucks up to 10 tonnes are all covered. Most jobs are a fixed $450 at the fuel pump, and we quote very large tanks on the phone before we come out.
How much does it cost to fix diesel in a petrol car in Melbourne?
Most jobs are a fixed $450 at the fuel pump or $475 roadside or at home, including GST with no card fees. Any parts needed, like spark plugs, are charged at cost. It is no fix, no fee. See our 2026 price guide.
Do you come out to the northern suburbs and near the airport?
Yes. We cover all of Melbourne 7 days a week, including Greenvale, Craigieburn, Broadmeadows, Tullamarine and Melbourne Airport, plus Geelong and regional Victoria. Call 1300 692 469 and we will give you an arrival time.
Wrong fuel in a big vehicle in Melbourne? Don’t keep cranking it. Call us on 1300 692 469 for a fixed price on the phone.
