How Worried Should You Be? Petrol in a Diesel Car in Woburn
Not started? Then less anxious than you probably feel. Until your ignition primes your pump, the starter turns, or the car is driven, petrol in a diesel tank simply waits there and does nothing. Which means the honest reply to that first Woburn question — "have I wrecked it?" — usually no. Leave your motor off and phone Petrol in Diesel — that keeps it that way. Below, you will find what petrol actually does inside a diesel, how far it may have got, and how to stop it happening to you again.
Petrol in a diesel: what does it do to the motor?
Diesel does two jobs on its way through a motor. Before it combusts, it protects — and then it ignites. Made to extremely fine gaps, the fuel injectors and the pump depend on your diesel flowing through them to keep their surfaces from wearing against one another.
Petrol does the first job badly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump on that mixture wearing itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the rattling.
The shape of the issue is clear once you put those together. It is circulation that causes the harm, not contact. A tank with petrol in it is a fuel issue. 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 fuel injectors beyond it.
Four scenarios our technicians see in Woburn: how bad is petrol in a diesel?
Fuelled, and never started: no case is better. At a forecourt, and really only there, that petrol is still confined to your tank — since everywhere else the vehicle was driven to reach it. The task is draining and flushing on the spot.
The ignition turned on, or a short start. The system has been bled, so petrol has left the tank and reached the filter and the fuel lines. Drain, flush, see to the fuel filter: still normally easy.
Those few miles driven meant your pump running on fuel thinned by petrol throughout. Miles is only half of it; how hard it was driven matters just as much. Either way this work includes that tank, the fuel lines, your filter and clean fuel through the whole system. Short trips, like the school run to Woburn Lower School, are one matter. Any mileage on the M1, under 3 miles from Woburn, means the engine working hard throughout, and a run to Milton Keynes, under 10 miles away, makes a very different job as well.
It protested, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. That's your engine telling you its fuel no longer is acting like diesel. Stop wherever you are — the verge on Park Street, a lay-by, a side street — then leave it where it is. The drain and flush-through still go first, and they sort it out: if a car is stopped early, permanent damage is very unusual.
Myths Woburn people hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. Percentage isn't how a diesel fuel system copes with petrol, however much that guidance assumes.
Myth: a current diesel copes with a bit of petrol. Rather, the opposite. A modern diesel sends its fuel through more precise parts at higher pressure, which makes the lubrication count more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that catches motorists. The motorist of a petrol motor fed diesel usually stops, since it will not run, and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile the pump grinds. Running isn't the same as fine.
An old workaround for a different issue lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." That petrol is still inside the tank after that, and whatever it has diluted is not put back.
The next start draws petrol back round the pump out of the fuel lines and your filter, where some of that ends up after your engine has run. That's why draining the tank yourself does not leave you sorted — a myth. It is also genuinely hazardous to drain petrol into a can at the roadside.
Petrol in a diesel: how does it occur?
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol car at all. The forecourt makes it simple, and the error runs one way.
Routine and the vehicle getting out of step is how it occurs. Courtesy car, hire car, or a car that is new. One petrol and one diesel on the driveway of the same household. The pumps in a different order on a well-known forecourt. Rushing for a train at Aspley Guise and filling up en route. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it happens. With rain, a call arriving, or children to deal with, the hand just does what it always has.
Next time you fill up in Woburn: avoiding petrol in a diesel
- 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, yet not on every forecourt.
- Check the filler flap. Many cars state the fuel type inside the flap or on the cap. Look at it on your first fill in a vehicle you don't know.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key if a house 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 daft. It does the trick.
- Put your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to refuse a petrol nozzle, and aftermarket devices exist for the remainder. Count it as a safety net, then keep reading the petrol pump.
- The moment you realise, stop: less petrol in that tank means a thinner mixture. What to do next doesn't change, though — still don't start the vehicle.
Petrol already in a diesel in Woburn? Begin here
The order of things is short, then. Don't switch your ignition on, and do not start it. The attendants on the forecourt — whether at Texaco itself or wherever you filled up — will normally help push it away from the petrol pump if you ask. Next, 0333 366 0103. We will ask what was put in, about how much, and if it's been run.
If it was AdBlue instead of petrol, say so. That's a separate problem — corrosion and deposits rather than lost lubrication — and it has its own page for Woburn.
One petrol in a diesel task in Woburn costs more than another. Why?
A fair single price doesn't exist here: four scenarios, four separate jobs. Chiefly, your cost moves with which situation you're in. Two things come after that: the petrol that went in as a proportion of what the tank takes, then the spot the car is in and whether a technician can get to it safely.
Ahead of any quote, not after, come three queries: the fuel that went in, the amount, and if it's run. That is why. A range becomes a straight figure when those replies are in.
About Woburn, for a moment
Woburn is a small town in Bedfordshire, situated inland at an elevation of around 122 metres, with semi-detached housing being the predominant type. Woburn lies near the larger town of Milton Keynes, and is also close to smaller settlements such as Speedwell and Birchmoor Green. Woburn is located approximately 39 miles north of London, making it a commuter town for some residents. Woburn has a population of around 958 people, according to recent estimates.
Across Bedfordshire and in Woburn: fuel drain cover
Our vans answering petrol in diesel calls around Woburn, in the MK postcode area, equally work the places around it, Speedwell, Birchmoor Green and Pinfoldpond included. A forecourt, a supermarket car park, a lay-by or your own drive are all places our technicians work, and the vehicle doesn't need to move to us.
In Woburn and still at the petrol pump?
The best place there is, then — that's where you are. Switched off it stays; then phone.