Should You Worry? Petrol in a Diesel Car in High Ercall
If it has not been started, you can worry far less than you likely are. "Have I wrecked it?" is the first question anyone around High Ercall asks, and the truthful answer is usually no, because petrol left in a diesel tank hurts nothing until it's drawn through your fuel system — by ignition priming, by your starter, or by driving. Petrol in Diesel is who to ring, with the engine kept off, and so it stays that way. Further down, you will find what petrol actually does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
What petrol in a diesel does to the motor
On its way through an engine, diesel has two jobs. It combusts, and before it ignites it lubricates. Your high-pressure pump and the fuel injectors are made to very fine gaps, and your diesel passing through them is what keeps those surfaces from wearing against one another.
The second task petrol doesn't do at all, and the first it does poorly. The knocking comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips out the protection the system depends on, and any pump working on such a mixture is wearing itself.
The shape of the issue is clear when you put those together. The harm is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel issue. Whatever a worn pump sheds goes on, borne by the fuel, into the fuel injectors further along, which is why a pump that has been working on that petrol is where a mechanical fault begins.
Four scenarios we see in High Ercall: how serious is petrol in a diesel?
Filled up, never started. The best case there is. The petrol is inside the tank and only the tank, and the job is a drain and a flush where the vehicle stands. This is the one scenario that can only truly occur at a forecourt, since anywhere else the vehicle has been driven to get there.
The ignition turned on, or a brief start. Once primed, the system has drawn petrol from the tank as far as your filter and the lines. Still generally easy: drain, flush, and the fuel filter sorted.
Those few miles on the road meant your pump running on fuel diluted by petrol throughout. The work is the tank, the fuel lines, the fuel filter and fresh fuel through the whole system, and how hard the car was driven counts as much as how far. Short trips, such as the school run to High Ercall Primary School, are one thing. Any mileage on the M54, under 5 miles from High Ercall, means the engine has worked hard throughout, and a run to Wolverhampton, under 25 miles away, is a very different job too.
Driven till it complained. Clattering, an uneven idle, smoke, a throttle that has gone soft. The fuel is not behaving like diesel any more, and the motor is telling you. Pull up on the spot — on the verge on Shop Lane, at the kerb, down a side road — and do not move it again. The fuel drain and flush-through still come first, and they deal with it: if a vehicle is stopped early, permanent damage is very unusual.
Petrol in a diesel myths High Ercall drivers hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. A bigger tank of the same mixture is all it gives, because topping up removes nothing. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance assumes.
If anything, the reverse is true. Myth: "A newer diesel can cope with a bit of petrol." Smaller components and higher pressure are the way a newer diesel runs its fuel, and that makes the protection count more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches motorists. Feed diesel to a petrol engine and it usually won't run, and so the motorist stops — and the damage stops with them. While the pump wears, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. A running engine doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different fault. What petrol has diluted remains diluted, and that petrol stays in the tank regardless.
If your engine has run, part of that petrol sits in the filter and the lines, not your tank — and the next start pulls it right back through your pump. So the myth "drain your tank yourself and you're sorted" does not hold. It is also really risky to drain petrol into a can by the kerbside.
How does petrol in a diesel occur?
A careless moment is rarely the cause, and no one means to do it. A diesel nozzle mostly won't fit a petrol vehicle, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake simple, and only in one direction.
When habit and the vehicle stop matching, it occurs. Courtesy car, hire car, or a motor that's new. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps laid out differently. Fuelling up in a rush en route to Wellington (Shropshire), with a train to catch. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Renault Clio for the first time. Throw in rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Preventing petrol in a diesel next time you fill up around High Ercall
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most usually do. Check the petrol pump's label; the colour is only a clue.
- Inspect your filler flap. Many vehicles state the fuel inside the flap or on the cap. Look at it on the first fill in a vehicle you do not know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of intending to remember, for a house with one of each.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car gets its first tank. It sounds daft. It does the trick.
- Tuck your phone away. This is an easy mistake to make while you're thinking about something else.
- Some diesels have a filler built to refuse a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- As soon as you realise, stop: less petrol in the tank makes a weaker mix. What to do next doesn't change, though — still do not fire it up.
Petrol already in a diesel around High Ercall? Start here
Short and simple, then, is the order of things. Do not switch your ignition on, and don't crank it. Still on the forecourt, at Pace or anywhere else? Ask the staff to help you roll the vehicle clear of the petrol pump. Next, 0333 366 0103. We will ask what got in, roughly how much, and if it has been run.
If it was AdBlue and not petrol, say so. That's a different problem — corrosion and deposits and not lost protection — and it has its own page for High Ercall.
One petrol in a diesel task around High Ercall costs more than another. Why?
A fair single price does not exist here: four situations, four separate jobs. Which of them you are in is mostly what moves the cost. Next it's the proportion — how much petrol went in against how much your tank holds — and after that where the car is and whether our van can get to it safely.
What got in, how much, and whether it has run — three questions our technicians ask before quoting, not after, for exactly that reason. A range becomes a straight figure when those answers are in.
About High Ercall, for a moment
High Ercall is a small village in Shropshire, situated in the inland countryside of the West Midlands region. High Ercall has a relatively low elevation of 72 metres and is located near several other small settlements, including Cotwall, Walton, and Osbaston. High Ercall is characterized by its predominantly detached housing stock and is home to a population of around 768 people. High Ercall is also within commuting distance of larger cities, with Wolverhampton approximately 23 miles away.
Fuel drain cover across Shropshire, High Ercall included
Cotwall, Walton and Osbaston are among the places around High Ercall that the same vans work, answering petrol in diesel jobs across High Ercall's TF postcode area. The vehicle does not need to move to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
High Ercall: still at the petrol pump?
No position is better: that's where you are. Keep it off. Call.