Put diesel in your petrol car? Here’s what actually happens
Alright, so you’ve rocked up to the BP on Te Rapa Road, not really thinking after a long day or just rushing between errands around Chartwell and Rototuna, and you’ve accidentally put diesel in your petrol car. Don’t stress, you’re definitely not the first – we see this pop up in the workshop more than most reckon. It doesn’t matter if you’re driving a Honda Fit, a Suzuki Swift, or even something a bit fancier like a Peugeot 307 or late model VW Polo. We had a customer a few weeks ago bring her Nissan Tiida in, flustered from a big day doing the school run out Morrinsville way, same issue. Happens to the best of us.
Now, compared to putting petrol in a diesel (that’s a bigger headache, trust me – more about that here), diesel in a petrol isn’t quite as nasty, but it’ll still stop your car in its tracks. Diesel’s heavier than petrol, so it sinks to the bottom of your tank and heads straight through your fuel lines once things get pumping. Next thing you know, that thick diesel’s heading for your fuel rail and wrecking your injectors, and your poor wee engine just can’t burn that stuff properly. You might get a block or two down Peachgrove Road, or even make it halfway to Cambridge if you’re real lucky, but sooner or later – she’ll splutter and die. The engine itself (pistons, valves, bits like that) usually comes through fine, but the fuel system cops all the drama. The car won’t run till that diesel’s gone. Simple as.
What should you do if you’ve mixed up your fuels?
If you’ve twigged before starting the engine, nice work – you’re in luck. Best move? Don’t touch the ignition. Don’t even turn the key – just get your car towed straight to a decent mechanic. If you try to drive it (even just to pop across to Countdown or The Base), the diesel will end up all through your pump and lines, making it a much bigger problem. Tow is always cheaper than new injectors, trust me.
For a bit more info, the AA has good advice up here.
How do we get diesel out of a petrol car?
Seen it all before. Doesn’t matter if it’s a Toyota Crown, Mazda Demio, or even one of those rare Citroën C3s – the fix is always a proper flush. The process sounds straightforward, but it’s messy:
- First off, we drain your whole tank – every last drop.
- Then we check the lines, rail and regulator, making sure no diesel’s lurking about.
- We’ll pull the injectors, clean them out good and proper. Some need to be pulled apart, sometimes even replaced if it’s real bad.
- Once that’s done, back in they go and we run the car on fresh petrol. If it all sounds sweet, she’s good to go again.
If you caught it early and no diesel’s in the engine or lines, sometimes just a full tank drain is all it takes. But if you tried starting it – especially on a cold Hamilton morning with everything fogged up, or after battling those potholes down Kahikatea Drive – then it’ll be a longer job. Your old, mixed-up fuel will need to be disposed of safely, too. Can’t use it in any engine after that, sadly.
Need a diesel flush in Hamilton?
If you’ve accidentally put diesel in your petrol tank, don’t panic. Our team at Grimmer Motors have sorted this out for all sorts of folks from Gordonton to Ngaruawahia, and even some out-of-towners from Tamahere. We know our way around a fuel system, whether it’s a Euro runabout, a Japanese import, hybrid repair, or your classic NZ ute that’s done the commute up and down Wairere Drive a thousand times. Our techs will get your fuel lines, injectors, fuel pump, regulator, the lot – all sorted and squeaky clean so you can get back on the road, no dramas.
If you need a fast, reliable diesel flush or any other car service Hamilton drivers might need, flick us a message, give us a bell, or just drop by. We’re always happy to help out and have a yarn about local car problems, WOF Hamilton stuff, or whatever you need.