How Worried Should You Be? Petrol in a Diesel Car in Steeple Aston
Far less than you probably are, if it has not been started. Petrol sitting in a diesel tank does nothing to your motor until something pulls it through the system — your ignition priming the pump, your starter, or the drive itself. So the fair answer to the first query anyone around Steeple Aston asks, "have I ruined it?", is usually no. Petrol in Diesel is who to call, with your motor left off, and so it remains that way. What petrol actually does to a diesel, how to gauge how far it's travelled, and how to keep it from happening a second time: that's the rest of this page.
The motor and petrol in a diesel: what goes on
Diesel has two tasks on its way through an engine. It protects to begin with, and after that does it burn. What stops the surfaces inside the high-pressure fuel pump and your injectors from wearing down against each other is the diesel flowing through them — they're designed to very fine tolerances.
Badly at the first, not at all at the second: that is petrol. It's runnier than diesel and takes away the protection the system depends on, so a pump running on a petrol blend is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That's where the rattling comes from.
Taken together, they make clear the shape the trouble takes. Not contact but circulation is what does the harm. Any tank with petrol in it is a fuel problem. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with the fuel to the injectors further on.
Steeple Aston, petrol in a diesel: four situations, from mild to major
The best case there can be: filled up, never started. Being at a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With the petrol kept inside the tank alone, it's emptied and cleaned right where it stands, and nothing more is needed.
Ignition on, or started for a second. Petrol has left the tank and got to the fuel filter and the lines, since the fuel system has been bled. That's generally still a simple task — a drain, a flush, and the fuel filter seen to.
Your pump now spent a few miles on thinned fuel — that is what driving it meant. Tank, lines, filter, then clean fuel run through the whole circuit: that is this work, and the way your car was driven counts as much as the mileage. Driving the kids to Dr Radcliffe's Church of England Primary School is one sort of trip. Any miles on the M40, under 5 miles from Steeple Aston, means the engine has worked hard throughout, and a run to Oxford, under 15 miles away, makes a very different job too.
Driven on until it protested — rattling, smoke, a lumpy idle, a soft throttle. The engine is telling you your fuel is no longer acting like diesel. Whether it's the verge on Harris Ville, a lay-by or a side road, stop there and leave it. Permanent damage is very rare if a car is stopped soon, and the fuel drain and flush-through that still come first take care of it.
Petrol in a diesel myths Steeple Aston people hear
False: topping up to full with diesel makes it fine. It does not. Topping up removes nothing; it gives you a bigger tank of the same mix. A diesel fuel system does not tolerate petrol by percentage in the way that advice presumes.
If anything, the reverse is true. Myth: "A modern diesel can cope with a bit of petrol." Protection counts more on current diesels, not less, because their fuel runs through smaller components at higher pressure.
This is the one that catches drivers. Myth: "If it starts and drives, there's no damage done." Feed diesel to a petrol engine and it usually won't run, and so the driver stops — and the damage stops with them. Feed petrol to a diesel and it generally fires up, idles and drives away like nothing has happened — all the while its pump wears. Fine and running aren't the same thing.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different issue. That petrol is still in the tank afterwards, and what it has weakened isn't put back.
The next start sends petrol back round your pump from the fuel lines and the fuel filter, where some of that ends up once your engine has been run. That's why draining the tank yourself doesn't leave you sorted — a myth. Clearing petrol into a can at the roadside is also genuinely hazardous.
How does petrol in a diesel take place?
It is rarely carelessness, and no one does it on purpose. The forecourt makes it easy: the petrol nozzle is the slimmer of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle mostly will not go into a petrol motor at all. So the error runs one way.
The moment routine stops matching your car is the moment it happens. Courtesy car, hire car, or a car that is new. One petrol and one diesel on the driveway of the same household. Your usual forecourt, its pumps suddenly in a different order. A train to catch, and a hurried fill en route to Heyford. Exactly the moment it occurs: after years of driving petrol, someone fills a diesel Renault Megane for the first time. With rain, a call coming in, or children to deal with, the hand simply does what it has always done.
Steeple Aston people: how to prevent petrol in a diesel next time
- A green handle for unleaded and black for diesel is normal in the UK — but not on every forecourt. Go by the label on the pump, not the colour.
- The first fill in an unfamiliar vehicle is the time to check the filler flap — on it, or on the cap, plenty of vehicles state the fuel to use.
- One of each in the house? Label your key to your diesel — a bright fob, a sticker — because intending to remember is not enough.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car gets its first tank. It sounds silly. It does the trick.
- Put the phone away. This is an easy mistake to make while you are thinking about something else.
- Some diesels come with a filler designed to refuse a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump.
- The moment you notice, stop: less petrol in your tank makes a weaker mix. What to do next does not change, though — still do not start the car.
Put petrol in a diesel in Steeple Aston already?
In that case, there's just a short order of things. Do not fire it up, and do not turn your ignition on. Ask the attendants to help you push it away from the pump if you are still at the forecourt, whether that is JET or anywhere else. Next, 0333 366 0103. We will ask what went in, about how much, and if it's been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate problem — Steeple Aston has a page just for it.
Why one petrol in a diesel job around Steeple Aston costs more than another
Four separate tasks sit behind the four scenarios above — which is why there's no fair single price. The situation itself does most of the work of moving your cost. After that it's the ratio — how much petrol went in against how much that tank holds — and then where the car is and whether a technician can get to it safely.
That's why our technicians ask three queries before costing rather than after: what was put in, how much, and whether it has run. With those answers, you get a straight figure rather than a range.
About Steeple Aston and where it is
Steeple Aston is a village in Oxfordshire, situated on the banks of a river at an elevation of around 112 metres. Steeple Aston has a population of approximately 630 residents, with a predominance of detached housing. Steeple Aston is located near several other small villages, including Hopcrofts Holt, Middle Aston, and Lower Heyford, and is about 12 miles from Oxford. Steeple Aston is also within commuting distance of London, being around 58 miles from the capital.
Steeple Aston and Oxfordshire: where our fuel drain cover reaches
Hopcrofts Holt, Middle Aston and Lower Heyford are among the locations around Steeple Aston that the same vans work, answering petrol in diesel jobs across Steeple Aston's OX postcode area. Our engineers drain wherever your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Steeple Aston: still at the pump?
No position is better: that is where you are. Call, and leave it turned off.