How Worried Should You Be? Petrol in a Diesel Car in Wicken
Not started? Then less worried than you probably feel. Everyone in Wicken begins with "have I wrecked it?", and the fair answer is generally no: petrol resting in that tank of any diesel remains harmless till priming, cranking or driving pulls it into the system. Keep it like that: leave the engine off and call 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 a second time.
Inside your engine: what petrol in a diesel does
Passing through a motor, diesel is doing two things at once. It protects first, and only then does it burn. The high-pressure fuel pump and your injectors are built to extremely fine tolerances, and the diesel passing through them is what keeps those surfaces from grinding against one another.
The second task petrol does not do at all, and the first it does poorly. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump running on the blend to wear itself. It is also made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the knocking.
Combined, those make the shape of the trouble plain. The harm is done by movement, not by contact. A tank with petrol in it is a fuel problem. Once the pump has been labouring on that petrol, a mechanical problem has begun: anything shed by a pump that's wearing down is carried downstream to your injectors with the fuel.
Wicken, petrol in a diesel: four situations, from mild to significant
Filled up, not once started. The best case there is. The petrol is in that tank and just that tank, and the job is a drain and a flush where the car stands. This is the one situation that can only truly happen at a forecourt, because anywhere else the vehicle has been driven to get there.
Started for a moment, or only the ignition on. Petrol has left your tank and got to the fuel filter and your lines, since the system has been bled. That's generally still a simple job — a drain, a flush, and the fuel filter seen to.
Driven a few miles. Now the pump has spent these miles running on weakened fuel. Mileage is only half of it; how hard it was driven matters equally. Either way this work runs to your tank, your lines, the filter and clean fuel through the entire system. Short trips, like the school run to St Andrew's CofE Primary School, are one matter. Very different a second time: a trip to Ely, under 10 miles away, or some mileage on the M11, under 15 miles from Wicken, where the engine kept working hard.
Driven till it protested. Knocking, a lumpy idle, smoke, a throttle that has gone soft. That's your engine telling you its fuel has stopped acting like diesel. Stop on the spot — on the verge on Butts Lane, at the kerb, down a side road — and do not move it. What goes first is still the fuel drain and flush-through, and that takes care of it, with long-term damage very uncommon if a car is stopped early.
Wicken motorists and the petrol in a diesel stories they hear
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Topping up removes nothing; it gives you a fuller tank of the same mix. Percentage is not how a diesel fuel system tolerates petrol, whatever that advice supposes.
If anything, the opposite is true. Myth: "A modern diesel can cope with a bit of petrol." A current diesel runs its fuel through finer parts at higher pressure, which makes the lubrication count more, not less.
This is the one that fools people. Myth: "If it starts and drives, there's no harm done." The driver of a petrol motor fed diesel usually has no choice but to stop, because it will not run, and the damage stops with them. Feed petrol to a diesel and it generally starts, idles and drives away like nothing happened — all while its pump is wearing. 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 weakened gets put back by it — and later, the tank still holds the petrol.
Myth: "Drain that tank yourself and you're sorted." After your engine has run, some of the petrol is no longer inside that tank: it's in the fuel filter and the lines, and it goes straight back through the pump at your next start. Clearing petrol into a can at the roadside is also genuinely dangerous.
Why petrol in a diesel takes place at all
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle generally won't fit a petrol motor, but the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error straightforward, and just in one direction.
Routine and the vehicle falling out of step is when it takes place. Hire cars, courtesy cars, and vehicles that are new to you. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Filling up in a hurry on the way to Soham, with a train to catch. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. The hand does what it has always done when you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel at your next fill-up in Wicken
- The label is what matters, and so read the pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- The first fill in a new car is the time to check your filler flap — inside it, or on the cap, plenty of motors state which fuel to use.
- One of each in the house? Mark your key to the diesel — a bright fob, a sticker — since meaning to remember is not enough.
- It seems silly and it works: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- Whilst you're thinking about something else, this is an easy mistake to make — so put your phone away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to reject a petrol nozzle, and aftermarket devices are available for the remainder. Treat it as a safety net, and keep reading the pump.
- Less petrol makes a thinner blend, and so stop the moment you notice — though remembering that the next step is unchanged. It's still not to fire it up.
Petrol already in a diesel around Wicken? Begin here
Short and simple, then, is the order of things. Don't switch your ignition on, and do not fire it up. If you're still on the forecourt — Esso or anywhere else — ask the staff to help you roll it away from the petrol pump. Next, 0333 366 0103. We'll ask what was put in, roughly how much, and if it's been run.
Say so if it was AdBlue instead of petrol: it is a separate problem, with its own page for Wicken, since AdBlue brings corrosion and deposits instead of lost lubrication.
One petrol in a diesel task around Wicken costs more than another. Why?
There is no honest single price for this, because the four situations above are four different tasks. Which of them you are in is mostly what moves your cost. Where the car is matters too, and whether our van can safely get to it, after the proportion of petrol to what that tank takes.
That's why we ask three queries before pricing rather than after: what was put in, how much, and whether it has run. A range becomes a straight figure once those answers are in.
About Wicken
Wicken is a small village in Cambridgeshire, situated on the riverside at a low elevation of around 9 metres. Wicken lies near the city of Ely and other nearby places such as Soham, Upware, and Newnham. Wicken has a population of approximately 745 people and predominantly consists of detached housing. Wicken is located about 58.6 miles from London, making it a rural community in the Eastern region.
Across Cambridgeshire and in Wicken: fuel drain cover
Soham, Upware and Newnham are among the locations around Wicken that the same teams work, answering petrol in diesel jobs across Wicken's CB postcode area. You need not move the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots where we work.
In Wicken and still at the petrol pump?
Then you're in the best place there can be. Switched off it stays; then phone.