Aggborough: Petrol in a Diesel Car? How Worried to Be
Provided it hasn't been started, worry far less than you probably are. "Have I ruined it?" is the first thing anyone in Aggborough asks, and the truthful answer is generally no, since petrol left in a diesel tank harms nothing till it is dragged through your fuel system — by ignition priming, by the starter, or by driving. Keep it like that: leave your engine off then call Petrol in Diesel. The remainder of this page covers what petrol really does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
Your engine and petrol in a diesel: what happens
Two tasks fall to diesel on its journey round a motor. Before it burns, it lubricates — and then it combusts. What stops the surfaces inside your high-pressure pump and your injectors from wearing down against each other is the diesel passing through them — they're designed to very fine gaps.
Petrol handles the first job badly and the second not at all. It is thinner than diesel and removes the protection your fuel system rests on, and so a pump running on a petrol blend is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the rattling comes from.
Seen together, they make clear the shape the problem has. It's circulation that does the harm, not contact. All a tank with petrol in it amounts to is a fuel issue. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to your injectors downstream.
Aggborough, petrol in a diesel: four cases, from mild to major
The best case there is: filled up, not once started. Being at a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With the petrol held inside your tank alone, it is emptied and rinsed right where it stands, and nothing more is needed.
Ignition on, or started for a moment. With your system primed, the fuel lines and filter now contain petrol that has come from the tank. Still usually easy: drain, flush, and the fuel filter sorted.
A couple of miles driven, and the pump has spent every one of them working on thinned fuel. How hard your car was driven matters as much as how far, and the work takes in the tank, the lines, the filter and fresh fuel through the entire system. Driving the children to Foley Park Primary Academy is one sort of trip. Any distance on the M5, under 10 miles from Aggborough, means your engine has worked hard throughout, and a run to Worcester, under 15 miles away, makes a very different job as well.
Driven till it complained. Clattering, a ragged idle, smoke, a throttle that has gone soft. That's your engine telling you its fuel has stopped acting like diesel. Whether it's the verge on College Road, a lay-by or a side road, stop where you are then leave it. What goes first is still the fuel drain and flush, and that deals with it, with long-term damage very uncommon if a car is stopped quickly.
Stories Aggborough motorists hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing comes out when you top up — that tank just carries more of the same blend. Percentage isn't how a diesel fuel system tolerates petrol, whatever that advice assumes.
If anything, the opposite is true. Myth: "A modern diesel can cope with a bit of petrol." A newer diesel sends its fuel through smaller parts at higher pressure, which makes the lubrication count more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there is no harm done." Diesel in a petrol motor usually means a motor that won't run: the motorist stops, and so does the harm. Feed petrol to a diesel and it generally starts, idles and drives away like nothing has happened — all while its pump is wearing. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct fault. What petrol has diluted remains diluted, and the petrol stays inside your tank regardless.
Once the engine has run, part of that petrol is in the fuel filter and the lines, not the tank — and the next start pulls it straight back through the pump. So the myth "drain that tank yourself and you're sorted" doesn't stand up. It is also truly risky to drain petrol into a can at the roadside.
How does petrol in a diesel happen?
It's seldom carelessness, and nobody does it on purpose. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle mostly will not go into a petrol motor at all. So the slip runs one way.
Habit and your car falling out of step is when it occurs. Courtesy car, hire car, or a car that's brand new. Households running one of each, petrol and diesel. Your ordinary forecourt, its pumps suddenly in a different order. A train to catch, and a hurried fill en route to Kidderminster. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. Add a back seat full of children, a phone call or rain, and habit takes over.
Next time you fill up around Aggborough: preventing petrol in a diesel
- The label is what matters, so check the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, yet not on every forecourt.
- Inspect your filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on the first fill in a car you do not know.
- Mark the key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Daft, perhaps, but it works.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away then keep your mind on the pump.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to reject a petrol nozzle, and aftermarket devices are available for the remainder. Treat it as a safety net, and keep reading the pump.
- Spotting it mid-fill? Stop there and then. A thinner mix follows from less petrol in that tank, yet your next step stays the same: do not start it.
Petrol already in a diesel around Aggborough? Start here
Then, there's only a short order of things. Do not turn your ignition on, and do not crank it. If you're still on the forecourt — Esso or anywhere else — ask the staff to help you push it away from the pump. Call 0333 366 0103 next, with three answers — the fuel, the rough amount, and if it's run.
Say so if it was AdBlue rather than petrol: it's a different issue, with its own page for Aggborough, because AdBlue brings corrosion and deposits rather than lost lubrication.
What makes one Aggborough petrol in a diesel task cost more than the next
Four separate tasks lie behind the four scenarios above — which is why there's no fair single quote. What shifts the cost is chiefly which of them you are in. The ratio matters next, meaning how much of the tank is petrol, and then the location of your car and whether getting to it is safe for our van.
That's why we ask three queries before costing instead of after: what got in, how much, and if it's run. Their answers are what turn a range into one firm number.
About Aggborough itself
Aggborough is a suburban area in Worcestershire, situated on the riverside at an elevation of 64 metres. Aggborough lies near the city of Worcester, approximately 12.8 miles away, and is surrounded by nearby places such as Hoobrook, Spennells, and Foley Park. Aggborough has a population of around 3100 residents, predominantly living in semi-detached housing.
Aggborough and Worcestershire: where our fuel drain cover runs
Our vans answering petrol in diesel calls in Aggborough, in the DY postcode area, also work the places around it, Hoobrook, Spennells and Foley Park among them. The vehicle does not need to move to us: our engineers drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Aggborough: still at the petrol pump?
The best place there is, then — that is where you are. Ring, and keep it switched off.