How Worried Should You Be? Petrol in a Diesel Car in Pitchcott
Provided it hasn't been started, worry far less than you likely are. Everyone in Pitchcott starts with "have I ruined it?", and the honest answer is usually no: petrol left inside your tank of any diesel stays harmless till priming, cranking or driving pulls it into the fuel system. Keep it like that: leave your engine off then ring Petrol in Diesel. Below, this page sets out what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you again.
Petrol in a diesel: what does it do to the motor?
Passing through an engine, diesel does two jobs at once. Before it burns, it protects — then it ignites. Made to very fine gaps, the injectors and your pump rely on your diesel moving through them to keep their surfaces from wearing against one another.
Of those two jobs, petrol handles the first poorly and the second never. A pump working on a petrol blend is wearing itself out, because petrol is runnier than diesel and takes away the protection the fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that is where the rattling comes.
Put these together and the shape of the trouble is clear. Contact does not do the harm — circulation does. Where the petrol is only in your tank, it's a fault of fuel, nothing more. The start of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with the fuel to the injectors downstream.
How bad is petrol in a diesel? Four scenarios our technicians see in Pitchcott
Filled up, not once started. The best case there is. That petrol is in the tank and only that tank, and the task is a drain and a flush where the vehicle stands. This is the one scenario that can only truly take place on a forecourt, since anywhere else your car has been driven to get there.
Started for a second, or only the ignition on. Petrol has come out of the tank and reached the filter and your lines, because your system has been primed. Drain, flush, deal with the fuel filter: still usually easy.
Those few miles driven were your pump working on fuel diluted by petrol the whole way. Miles is only half of it; how hard it was driven matters just as much. Either way this work includes your tank, the fuel lines, the fuel filter and clean fuel through the entire circuit. On the school run to Whitchurch Combined School, the miles is small. A run as far as Milton Keynes, under 15 miles away, is a very different task. So is any distance on the M40, under 15 miles from Pitchcott, where your engine has been working hard the whole time.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. That's the engine telling you its fuel no longer is acting like diesel. Leave it wherever it stops: a lay-by, a side street, the verge on Pitchcott Road. What comes first is still the drain and flush, and that takes care of it, with permanent damage very unusual if a vehicle is stopped early.
What Pitchcott motorists get told about petrol in a diesel — and the stories in it
False: topping up to full with diesel makes it fine. It doesn't. Topping up takes out nothing; it gives you a fuller tank of the same mix. A diesel fuel system does not accept petrol by percentage in the way that advice presumes.
"Current diesels can handle a little petrol" — a myth, and closer to the opposite. A newer diesel sends its fuel through more precise parts at higher pressure, which makes the protection matter more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up more drivers than any other. Feed diesel to a petrol motor and it usually won't run, so the driver stops — and the damage stops with them. Feed petrol to a diesel and it normally starts, idles and drives away like nothing has happened — all the while its pump wears. Running isn't the same as fine.
Myth: a two-stroke additive lets you to drive home. It was an old fix, supposed for another fault. None of what petrol thinned gets put back by it — and afterwards, your tank still holds the petrol.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol lies in the filter and lines, ready to go right back through your pump on the next start. On top of that, petrol cleared into a can by the road is genuinely hazardous.
Why petrol in a diesel happens so easily
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle mostly will not go into a petrol vehicle, yet the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake easy, and only in that direction.
When routine and your car stop matching, it happens. Any motor that is new to you — a hire car, on loan as a courtesy car, or just bought. One petrol and one diesel on the drive of the same household. A familiar forecourt with the pumps in a different order. A train to catch, and a rushed fill on the way to Aylesbury Vale Parkway. Precisely the moment it happens: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. Add rain, a phone call or a back seat full of kids, and the hand repeats what it has always done.
Pitchcott drivers: how to prevent petrol in a diesel next time
- Read the pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on every forecourt. The label is what matters.
- In a car you do not know, look inside the flap over the filler or at the cap before the first fill: many motors print the fuel type there.
- One of each in the house? Label the key to the diesel — a bright fob, a sticker — because meaning to remember isn't enough.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new car, say "diesel" aloud. Daft, yes, but it does the trick.
- Put your phone away. This is an easy mistake to make while you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to reject a petrol nozzle, and add-on devices are available for motors without one. They are a backstop, not a reason to stop checking the petrol pump.
- Stop as soon as you realise. Less petrol inside your tank makes a thinner mix. It does not change what to do next, which is still not to crank it.
Already put petrol in a diesel around Pitchcott?
Then the order of things is short. Starting it is out, and so is switching on your ignition. Yet on the forecourt, at Gulf or anywhere else? Ask the staff to help you roll the car clear of the pump. Ring 0333 366 0103 next, with three facts — your fuel, the rough quantity, and whether it's run.
Corrosion and deposits are the problem with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and read its own Pitchcott page.
One petrol in a diesel job around Pitchcott costs more than another. Why?
Four separate tasks lie behind the four situations above — which is why there's no honest single quote. The situation itself does most of the work of moving your cost. Where your car is counts too, and whether a technician can safely get to it, after the proportion of petrol to what your tank takes.
That is why our engineers ask three questions before quoting rather than after: what went in, how much, and whether it has run. Those answers turn a range into a straight figure.
About Pitchcott, briefly
Pitchcott is a small hamlet in Buckinghamshire, situated in the inland countryside of the South East region. Pitchcott sits at an elevation of around 137 metres, approximately 40 miles from London and 13 miles from Milton Keynes. Pitchcott is surrounded by nearby places such as Oving, Hunters Yard, and North Marston, and is characterised by its predominantly detached housing stock. Pitchcott has a population of around 534 residents.
Across Buckinghamshire and in Pitchcott: fuel drain cover
Pitchcott waits in the HP postcode area, and our vans that answer petrol in diesel calls there work the locations near it as well — Oving, Hunters Yard and North Marston among them. The car doesn't need to move to us: we drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Pitchcott: still at the petrol pump?
No position is better: that is where you are. Leave it switched off, then ring.