What happens if you put petrol in a diesel car in Hamilton?
Right, so you’re just about to shoot through to Morrinsville for the weekend, or maybe heading out to catch a mate in Cambridge, you stop for a quick fill on Peachgrove Road, and—bugger!—you accidentally put petrol into your diesel Mazda CX-5 or maybe your Toyota Hilux. Trust me, you’re not the first. Happens more than you think, especially with newer pumps and those days when you’re in a rush because Hamilton traffic is doing its usual stop-start circus on Boundary Road.
Anyway, if you’ve put petrol into a diesel, it can muck up the engine real quick. Diesel engines need the right stuff (diesel, of course) for a reason. Petrol doesn’t lubricate the pump or the injectors—so once that petrol gets into the works, it starts stripping all the lubrication away. Next thing, you’ve got bits inside grinding up against each other, and before you know it, you’re getting metal filings in your fuel system. Seen it plenty of times—everything from European wagons like a Skoda Superb to smaller Asian utes like the Isuzu D-Max. Doesn’t matter if it’s summer heat out in Tamahere or a foggy winter morning in Rototuna, it causes headaches either way.
If the mixed fuel’s been running through your system, you might notice:
- Engine’s a bit rough, feels like it’s running on 2 cylinders
- Acceleration’s hopeless—you put your foot down on Te Rapa Straight, and it barely goes
- Heaps more smoke out the back, especially on cold starts
- Struggling to start up, or won’t start at all
- Odd knocking or clanking noises from under the bonnet (that’s never a good sign)
What should you do if you fill up with the wrong fuel?
The main thing? Don’t panic—and definitely don’t keep driving. If you realise straight away, don’t even start the car. If you’re already rolling down Ulster Street and something feels off, pull over somewhere safe and switch off, right then and there.
- Turn the engine off. Every second it runs, the petrol’s working its way deeper into the system, so shut it down as soon as you can. Don’t try to “drive it home”—we see that mistake often, and it almost always ends up much worse for the wallet.
- Don’t try and move it yourself. Pushing that mix through the fuel system is where the real damage happens. Just leave it be, call someone for help.
- Ring a pro. Get your vehicle towed to a proper workshop (like us at Grimmer Motors, hint hint). Our techs have drained all sorts—everything from Honda CR-Vs to Audi Q5s after a busy day at the pumps. Trust us, a tow is cheap compared to replacing pumps and injectors.
- Let the mechanic drain and flush everything. We’ll suck all the bad juice out, clean the lines and fuel filters, and if needed, sort out any repairs—injectors, pumps, whatever’s taken a hit. Have a peek at fuel injector repairs if you’re curious.
- If there’s any damage, we’ll fix it. That could mean new filters, pumps, sometimes more. Depends how much petrol got in and how far you drove. Every case is different—seen a Nissan Navara that needed a whole pump, and a Volvo XC70 that was sweet after a flush.
The longer you leave it, the worse and pricier it gets. These modern diesels, especially the ones zipping around Chartwell or Flagstaff, their injectors don’t muck around—bit of petrol and they’re kaput.
If you want to dive a little deeper, here’s another good yarn to check out: Learn more about what to do >
Petrol in your diesel tank? We flush and fix it in Hamilton
From those potholes near Dinsdale to bouncing over speed bumps outside The Base, your car gets enough of a workout already. Don’t let wrong fuel kill your ride. At Grimmer Motors, we’re set up to flush the wrong fuel out of all sorts—Subarus, Kias, Citroens, you name it. If petrol’s hit the diesel tank, we’ll drain it quick, tidy up anything that’s taken a knock, and get you back on the road safely. From quick flushes to sorting out mashed pumps, we’ve got it handled.
Need fuel draining, injector repairs, or just solid car service in Hamilton? Flick us a message, give us a bell, or pop by the workshop—we’ve sorted cars from Taupiri to Ohaupo. We’ll look after you.