Madeley: Petrol in a Diesel Car? How Worried to Be
Probably less than you are now — as long as nobody has started the car. "Have I wrecked it?" is the first question anyone around Madeley asks, and the honest answer is generally no, because petrol resting in a diesel tank harms nothing until it's drawn through the system — by ignition priming, by your starter, or by being driven. Leave the motor off and phone Petrol in Diesel — that keeps it like that. What petrol actually does to a diesel, how to gauge how far it's gone, and how to keep it from happening a second time: that is the remainder of this page.
The engine and petrol in a diesel: what happens
Passing through a motor, diesel is doing two things at once. Lubricating comes before burning; it does both. Very fine tolerances are built into the fuel injectors and your high-pressure pump, and just the diesel running through stops their surfaces grinding together.
Petrol handles the first job badly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump on the blend wearing itself. It's equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the knocking.
Together, those leave the shape of the issue plain. Contact does not do the harm — circulation does. Any tank with petrol in it is a fuel problem. The start of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with your fuel to the injectors downstream.
Madeley, petrol in a diesel: four situations, from mild to significant
Fuelled, and never started: no case is better. That petrol is in that tank and only your tank, and the job is a drain and a flush where your car sits. This is the one scenario that can only really happen at a forecourt, because anywhere else the car has been driven to get there.
Ignition on, or started for a second. Petrol has come out of your tank and reached the fuel filter and the lines, since your system has been primed. Normally little more than clearing, purging and sorting your filter, and so still straightforward.
Driven a few miles. Now your pump has spent those miles working on thinned fuel. Miles is only half of that; how hard it was driven matters just as much. Either way the work runs to the tank, the fuel lines, your filter and clean fuel through the entire circuit. On the school run to John Fletcher of Madeley Primary School, the miles is small. Very different a second time: a trip to Wolverhampton, under 15 miles away, or some mileage on the M54, under 5 miles from Madeley, where the engine never stopped running hard.
Knocking, a ragged idle, smoke, a throttle gone soft: driven till it complained. What you are hearing is your engine signalling fuel that no longer runs like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Betnell Grove. Lasting damage is very uncommon when a vehicle is stopped quickly, and the fuel drain and flush that still come first deal with it.
Petrol in a diesel stories Madeley drivers hear
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you are left with a fuller tank, still the same mixture. The assumption behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
"Modern diesels can handle a little petrol" — a myth, and closer to the opposite. Protection counts more on current diesels, not less, since their fuel runs through smaller parts at higher pressure.
Myth: "If it starts and drives, there's no damage done." This is the one that fools drivers. Any petrol motor fed diesel usually won't run, so the driver stops and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile the pump grinds. Running isn't the same as fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an outdated workaround for a distinct issue. What petrol has diluted remains diluted, and the petrol stays in the tank anyway.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol sits in the filter and lines, waiting to go right back through the pump at the next start. And, a can of petrol drained at the kerbside is truly hazardous.
How does petrol in a diesel happen?
It's rarely carelessness, and no one does it on purpose. A diesel nozzle mostly will not go into a petrol motor, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in that direction.
Routine and the vehicle getting out of step is how it occurs. A car that's new to you — a hire car, on loan as a courtesy car, or brand new. Two cars on one drive, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. A hurried fill on the way to Telford Central with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: precisely when it takes place. Add a back seat full of kids, a phone call or rain, and habit wins.
How to prevent petrol in a diesel on your next fill-up in Madeley
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Check the pump's label; the colour is just a clue.
- The first fill in a new vehicle is the time to check your filler flap — inside it, or on the cap, plenty of cars state the fuel to use.
- Good intentions count for less than a sticker or a fob in a vivid colour on your diesel's key when a house has one of each. So mark it.
- Before the nozzle leaves the petrol pump the first time you fuel a hired or new car, say "diesel" aloud. Silly, yes, yet it does the trick.
- Mistakes like this are straightforward to make whilst your mind is on something else, and so your phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to refuse a petrol nozzle, and add-on devices are available for motors without one. They are a safety net, not a reason to stop reading the pump.
- As soon as you realise, stop: less petrol inside the tank makes a weaker mixture. What to do next doesn't change, though — still do not fire it up.
Petrol already in a diesel around Madeley? Start here
Short and simple, then, is the order of things. Leave it unstarted, with your ignition off too. The staff at the forecourt — whether at Esso itself or wherever you filled up — will usually help roll it clear of the petrol pump if you ask. What was put in, about how much, and if it has run: tell us those when you ring 0333 366 0103.
Corrosion and deposits are the problem with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and read its own Madeley page.
What makes one Madeley petrol in a diesel job cost more than the next
The four scenarios above are four separate tasks, so no single price for this would be fair. What moves the cost is chiefly which of them you are in. Where the vehicle is matters too, and whether a technician can safely reach it, after the ratio of petrol to what the tank holds.
That's why our technicians ask three questions before pricing rather than after: what was put in, how much, and if it has run. A range becomes a straight figure once those replies are in.
About Madeley, for a moment
Madeley is a suburban area in Shropshire, situated on the riverside with an elevation of around 133 metres. Madeley lies near the Ironbridge Gorge, close to notable spots like Blists Hill and Sutton Hill. Madeley has a mix of housing types, but predominantly features terraced homes. Madeley is located near Wolverhampton, at a distance of approximately 14 miles, and is about 126 miles northwest of London.
Fuel drain cover in Madeley and across Shropshire
Our teams answering petrol in diesel calls in Madeley, in the TF postcode area, equally work the spots near it, Blists Hill, Tweedale and Sutton Hill included. Our technicians drain wherever the vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the petrol pump around Madeley, right now?
No position is better: that is where you are. Call, and leave it switched off.