How Worried Should You Be? Petrol in a Diesel Car in Seavington St Michael
Unstarted? Then less anxious than you probably are. "Have I wrecked it?" is the first thing everyone in Seavington St Michael asks, and the truthful answer is usually no, because petrol left in a diesel tank harms nothing until it's drawn through the fuel system — by ignition priming, by the starter, or by being driven. Keep it like that: leave the engine off then call Petrol in Diesel. The rest of this page covers what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you a second time.
Inside your engine: what petrol in a diesel really does
On its way through an engine, diesel has two jobs. It ignites, and before it ignites it lubricates. The high-pressure fuel pump and your injectors are designed to very fine clearances, and the diesel passing through them is what stops those surfaces from grinding against one another.
Petrol does the first task poorly and the second not at all. It is thinner than diesel and takes away the lubrication the fuel system hinges on, and 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 reverse of what a diesel needs from its fuel. That's where the rattling comes from.
Combined, those leave the shape of the issue clear. It is movement that causes the harm, not contact. All a tank with petrol in it amounts to is a fuel issue. Once your pump has been working on that petrol, a mechanical fault has begun: whatever is shed by a pump that is wearing travels downstream to the fuel injectors with your fuel.
How bad is petrol in a diesel? Four situations we see around Seavington St Michael
The best case there can be: filled up, never started. Being at a forecourt is what makes this the case: elsewhere, the vehicle has been driven there to begin with. With the petrol kept in the tank alone, it is drained and rinsed right where it stands, and nothing more is needed.
Ignition on, or started for a second. The system has been primed, and so petrol has left your tank and got to the fuel filter and your lines. Usually nothing more than clearing, cleaning and sorting the fuel filter, and so still straightforward.
Those few miles on the road meant the pump labouring on fuel weakened by petrol the whole way. How hard the vehicle was driven counts as much as how far, and the work covers your tank, your lines, the filter and fresh fuel through the whole system. Driving the children to Shepton Beauchamp Church School is one sort of trip. Any distance on the M5, under 15 miles from Seavington St Michael, means your engine working hard throughout, and a run to Wells, under 25 miles away, makes a very different job too.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. The fuel is not acting like diesel any more, and your motor is saying so. Stop where you are — on the verge on Water Street, at the kerb, down a side road — and do not move it again. Permanent damage is very unusual when a vehicle is stopped quickly, and the drain and flush-through that still come first deal with it.
Petrol in a diesel myths Seavington St Michael motorists hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Topping up removes nothing; it gives you a bigger tank of the same mix. Percentage isn't how a diesel fuel system copes with petrol, however much that advice assumes.
Myth: a current diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through finer parts: that is how a current diesel handles its fuel, and so the lubrication matters more, not less.
The myth that catches drivers out: if it starts and drives, it must be unharmed. A petrol engine fed diesel generally will not run, so the motorist stops and the damage stops with them. Whilst the pump wears, a diesel fed petrol usually starts, idles and drives away as though nothing has happened. Running does not mean fine.
Myth: "Add some two-stroke oil and drive the car home." It's an outdated workaround for a separate issue. That petrol is still inside your tank after that, and whatever it has weakened is not put back.
If your engine has run, part of that petrol is in your filter and your lines, not that tank — and the next start sends it straight back through the pump. So the myth "drain the tank yourself and you are sorted" does not hold. It is also truly dangerous to drain petrol into a can by the roadside.
How does petrol in a diesel happen?
It is seldom carelessness, and no one 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 generally won't go into a petrol car at all. So the error runs one way.
It occurs when routine and your car stop matching. Courtesy car, hire car, or a car that is new. Two motors on one drive, one petrol, one diesel. A well-known forecourt with the pumps in a different order. A hurried fill on the way to Crewkerne with a train to catch. Exactly the moment it happens: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. With rain, a call coming in, or a car full of children to deal with, the hand just does what it has always done.
Next time you fill up in Seavington St Michael: preventing petrol in a diesel
- Read the pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what counts.
- Inspect your filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on the first fill in any car you do not know.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key if a household has one of each. So label it.
- "Diesel", out loud, before you lift the nozzle — each time a new or hired car needs its first tank. It seems silly. It works.
- While you are thinking about something else, this is an easy mistake to make — so put your phone away.
- Add-on devices exist for motors without one, and some diesels are built with a filler that won't take a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label.
- Less petrol makes a thinner mixture, and so stop the moment you realise — while remembering that your next step is unchanged. It is still not to crank it.
Put petrol in a diesel around Seavington St Michael already?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition switched off too. The staff at the forecourt — whether at Esso itself or wherever you filled up — will normally help push it clear of the petrol pump if you ask. Ring 0333 366 0103 next, with three answers — the fuel, the approximate volume, and whether it has run.
If it was AdBlue instead of petrol, say so. That's a different issue — corrosion and deposits instead of lost lubrication — and it has its own page for Seavington St Michael.
Why one petrol in a diesel job around Seavington St Michael costs more than another
The four situations above are four separate jobs, so no single quote for this would be fair. The scenario itself does most of the work of moving the cost. Two things come after that: the petrol that went in as a share of what the tank holds, then the place the car is in and whether a van can reach it safely.
That's why our engineers ask three queries before pricing rather than after: what was put in, how much, and if it has run. With the replies, you get a straight figure instead of a range.
About Seavington St Michael and its setting
Seavington St Michael is a small village in Somerset, situated inland at an elevation of around 60 metres. Seavington St Michael lies near the villages of Seavington St Mary and Lopen Head, and is approximately 20 miles from the city of Wells. Seavington St Michael has a population of around 521 people, predominantly living in detached houses.
Across Somerset and around Seavington St Michael: fuel drain cover
Petrol in diesel calls in Seavington St Michael — part of the TA postcode area — go to teams that likewise cover the places around it, Seavington St Mary, Broomhill and Lopen Head among them. You need not bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
In Seavington St Michael and still at the petrol pump?
Nothing beats it: that's where you are. Keep it switched off, then ring.