Heron Cross: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less anxious than you likely are. Everyone around Heron Cross begins with "have I ruined it?", and the honest answer is normally no: petrol left in that tank of any diesel stays harmless until priming, cranking or driving pulls it into the system. To keep the vehicle that way, call Petrol in Diesel and leave the engine switched off. What petrol really does to a diesel, how to judge how far it has gone, and how to stop it from happening again: that's the remainder of this page.
Petrol in a diesel: what does it do to the engine?
Two jobs fall to diesel on its journey through a motor. It combusts, and before it combusts it protects. Made to extremely fine clearances, the fuel injectors and the pump rely on the diesel moving through them to keep their surfaces from wearing against one another.
Petrol handles the first job badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump on the blend wearing itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the knocking.
Put these together and the shape of the issue is clear. Not contact but circulation is what does the harm. Where the petrol is only inside that tank, it's a problem of fuel, nothing more. Whatever a worn pump sheds goes on, carried by your fuel, into the fuel injectors downstream, which is why a pump that has worked on the petrol is where a mechanical issue starts.
Four situations we see in Heron Cross: how serious is petrol in a diesel?
The best case there can be: filled up, never started. That petrol is inside the tank and just your tank, and the job is a drain and a flush where the vehicle sits. This is the one scenario that can only really occur at a forecourt, since anywhere else your car has been driven to get there.
Started for a second, or just your ignition on. With the system primed, the fuel lines and filter now contain petrol that has come from the tank. Still usually simple: drain, flush, and the filter seen to.
Your pump has worked a few miles on weakened fuel — that's what driving the car does. Distance is only half of that; how hard it was driven matters just as much. Either way this work includes the tank, the lines, the filter and fresh fuel through the whole circuit. A school run to Heron Cross Primary School is one matter. Driving as far as Stoke-on-Trent, under 3 miles away, makes a very different task — as does any miles on the M6, under 3 miles from Heron Cross, with your engine running hard all the way.
Driven until it complained. Clattering, a lumpy idle, smoke, a throttle that has gone soft. What you are hearing is your motor signalling fuel that no longer runs like diesel. Stop where you are — on the verge on Chilton Street, at the kerb, down a side road — and do not move it again. The drain and flush-through still come first, and they deal with it: when a vehicle is stopped soon, permanent damage is very rare.
Myths Heron Cross drivers hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It does not. Topping up removes nothing; it gives you a fuller tank of the same mix. A diesel fuel system doesn't accept petrol by percentage in the way that advice presumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. Protection counts more on modern diesels, not less, because their fuel passes through smaller components at higher pressure.
The myth that catches people out: if it starts and drives, it must be unharmed. Diesel in a petrol motor generally means a motor that will not run: the motorist stops, and so does the damage. Whilst your pump wears, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. Running doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate fault. None of what petrol weakened gets put back by it — and later, that tank still holds the petrol.
The next start sends petrol back round the pump out of the lines and the filter, where some of that sits after your engine has run. That's why draining your tank yourself doesn't leave you sorted — a myth. Emptying petrol into a can by the kerbside is also genuinely hazardous.
Why petrol in a diesel occurs at all
Carelessness is rarely the cause, and nobody means to do it. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle generally won't go into a petrol vehicle at all. So the mistake runs one way.
Routine and the vehicle falling out of step is how it occurs. A new car, a hire car or a courtesy car. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps arranged differently. Filling up in a rush en route to Longton, with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is precisely the moment it happens. With rain, a call coming in, or children to deal with, your hand just does what it always has.
Avoiding petrol in a diesel next time you fill up around Heron Cross
- Check the pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what matters.
- The first fill in an unfamiliar car is the time to check the filler flap — inside it, or on the cap, plenty of motors state the fuel they take.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key when a home has one of each. So label it.
- Before the nozzle comes off the pump the first time you fill a hired or new motor, say "diesel" out loud. Daft, perhaps, yet it does the trick.
- Whilst you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to block a petrol nozzle, and aftermarket devices are available for the rest. Count it as a backstop, then keep reading the pump.
- Less petrol makes a thinner mix, and so stop as soon as you notice — though remembering that your next step is unchanged. It is still not to start the vehicle.
Put petrol in a diesel around Heron Cross already?
Then, there's only a short order of things. Don't switch your ignition on, and don't start it. If you're still on the forecourt — Asda or anywhere else — ask the attendants to help you push it away from the petrol pump. Next, 0333 366 0103. We will ask what was put in, about how much, and if it's been run.
Corrosion and deposits form the trouble with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and see its own Heron Cross page.
What makes one Heron Cross petrol in a diesel task cost more than the next
The four situations above are four different tasks, so no single price for this would be fair. What shifts your cost is mostly which of them you are in. The share counts next, meaning how much of that tank is petrol, followed by the location of the car and whether getting to it is safe for a van.
Three questions come first, before any quote, instead of after — what got in, how much, has it run — and this is the reason. Their replies are what change a range into one firm number.
About Heron Cross
Heron Cross is a suburban area located on the outskirts of Stoke-on-Trent in Staffordshire, situated near the River Trent at an elevation of 134 metres. Heron Cross is characterized by its semi-detached housing stock and is close to nearby places such as Fenton and Hollybush. Heron Cross sits approximately 2.1 miles from Stoke-on-Trent city centre and is about 133.9 miles northwest of London. Heron Cross has a population of around 4005 residents.
Heron Cross and Staffordshire: where our fuel drain cover runs
Fenton, Hollybush and Fenton Low are among the places near Heron Cross that the same vans work, answering petrol in diesel jobs across Heron Cross's ST postcode area. The vehicle does not need to come to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Heron Cross and still at the pump?
Then you're in the best spot there can be. Switched off it stays; then phone.