Petrol in a Diesel Car in Hale: How Worried Should You Be?
Not started? Then less anxious than you likely feel. "Have I wrecked it?" is the first thing anyone around Hale asks, and the truthful answer is generally no, because petrol left in a diesel tank hurts nothing till it is drawn through the system — by ignition priming, by your starter, or by being driven. Keep it like that: leave your motor off then ring Petrol in Diesel. Further down, this page sets out what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Your engine and petrol in a diesel: what happens
Passing through an engine, diesel is doing two things at once. It protects to begin with, and only then does it burn. What stops the surfaces inside the high-pressure fuel pump and the fuel injectors from wearing down against one another is the diesel flowing through them — they're designed to very fine tolerances.
Of these two tasks, petrol manages the first badly and the second never. Being less viscous than diesel, petrol strips away the protection a fuel system needs, so a pump running on that mixture wearing itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the knocking.
Put these together and the shape of the trouble is clear. Not contact but circulation is what does the damage. Where that petrol is only inside your tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds goes on, borne by the fuel, into the injectors downstream, which is why a pump that has been working on the petrol is where a mechanical issue starts.
How serious is petrol in a diesel? Four situations our engineers see around Hale
Filled up, never started. The best case there is. That petrol is inside your tank and just the tank, and the job is a drain and a flush where the car stands. This is the one situation that can only truly occur at a forecourt, since anywhere else the vehicle has been driven to get there.
The ignition switched on, or a short start. Once primed, the system has drawn petrol out of your tank as far as the filter and the lines. Still normally straightforward: drain, flush, and your filter dealt with.
The pump now spent a couple of miles on diluted fuel — that's what driving the car does. The work is that tank, the fuel lines, the filter and fresh fuel through the whole system, and how hard the vehicle was driven matters as much as how far. The school run to William Cobbett Primary School is one matter. Very different once more: a run to Winchester, under 50 miles away, or any mileage on the M3, under 10 miles from Hale, where the motor kept working hard.
Driven till it protested. Knocking, a ragged idle, smoke, a throttle that has gone soft. The fuel is not acting like diesel any more, and the engine is saying so. Stop on the spot — on the verge on Farnborough Road, at the kerb, down a side road — and do not move it. What comes first is still the drain and flush, and that deals with it, with lasting damage very uncommon if a vehicle is pulled over quickly.
Petrol in a diesel myths Hale drivers hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Topping up removes nothing; it gives you a fuller tank of the same mixture. That advice assumes a diesel fuel system tolerates petrol by percentage. It doesn't.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." More precise components and higher pressure are how a newer diesel runs its fuel, and that makes the protection matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no harm done." Any petrol motor fed diesel normally will not run, and so the motorist stops and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump grinds. Being able to run is not the same as being fine.
Myth: a two-stroke additive lets you to drive home. It was an old fix, meant for another problem. None of what petrol diluted is put back by it — and later, the tank still contains that petrol.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol sits in your filter and lines, ready to go straight back through the pump on the next start. Also, a can of petrol filled by the roadside is truly risky.
Why petrol in a diesel occurs so easily
Carelessness is seldom the cause, and nobody means to do it. 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, while a diesel nozzle generally will not go into a petrol car at all. So the slip runs one way.
The moment routine stops matching the vehicle is the moment it occurs. Courtesy car, hire car, or a motor that is new. A household with one petrol and one diesel on the driveway. Your ordinary forecourt, its pumps suddenly in a different order. Filling up in a hurry on the way to Farnham, with a train to catch. Precisely the moment it occurs: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. With rain, a call coming in, or children to deal with, your hand simply does what it always has.
Preventing petrol in a diesel next time you fill up in Hale
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Check the petrol pump's label; the colour is just a hint.
- Inspect the filler flap. Many vehicles state the fuel type inside the flap or on the cap. Look at it on the first fill in a motor you do not know.
- One of each in the household? Mark the key to your diesel — a bright fob, a sticker — because intending to remember is not enough.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump. It sounds silly and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so tuck the phone away then keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to block a petrol nozzle, and add-on devices exist for cars without one. They are a safety net, not a reason to stop checking the petrol pump.
- Less petrol means a thinner blend, so stop the moment you notice — though remembering that your next stage is unchanged. It's still not to crank it.
Put petrol in a diesel in Hale already?
Then the order of things is brief. Starting it is out, and so is turning on the ignition. The staff on the forecourt — whether at BP itself or wherever you filled up — will normally help roll it clear of the pump if you ask. Call 0333 366 0103 next, with three facts — the fuel, the rough volume, and if it's run.
Corrosion and deposits are the issue with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and see its own Hale page.
Why one petrol in a diesel task in Hale costs more than another
There's no fair single price for this, because the four situations above are four separate jobs. Chiefly, the cost shifts with which one you are in. Where the car is matters too, and whether a van can safely get to it, after the ratio of petrol to what that tank holds.
What was put in, how much, and whether it's run — three queries our technicians ask before costing, not after, for precisely that reason. With those answers, there is a straight figure rather than a range.
About Hale and its setting
Hale is a village situated on the River Wey in Surrey, with a mix of rural and suburban characteristics. Hale sits at an elevation of around 94 metres, surrounded by nearby places such as Weybourne, Heath End, and Upper Hale. Hale has a population of approximately 1633 residents, predominantly living in detached housing. Hale is located near the city of Winchester, about 25.6 miles away, and is also within commuting distance to London, around 34.3 miles away.
Fuel drain cover across Surrey, Hale included
Petrol in diesel call-outs around Hale — part of the GU postcode area — go to vans that also cover the locations around it, Weybourne, Heath End and Upper Hale included. Our engineers drain wherever your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
In Hale and still at the pump?
The best place there is, then — that's where you are. Phone, and keep it turned off.