The Coppice: Petrol in a Diesel Car? How Worried to Be
Provided it has not been started, you can worry far less than you probably are. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through your fuel system — the ignition priming your pump, your starter, or driving itself. So the fair answer to the first question anyone in The Coppice asks, "have I ruined it?", is normally no. Petrol in Diesel is who to ring, with your motor left off, and so it remains that way. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to stop it from happening a second time: that is the rest of this page.
What petrol in a diesel does to your engine
Diesel does two jobs on its way through a motor. It protects to begin with, and only then does it burn. Designed to extremely fine clearances, your injectors and your pump rely on the diesel flowing through them to stop their surfaces wearing against one another.
The second job petrol doesn't do at all, and the first it does badly. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump running on the mixture to wear itself. It is equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the knocking.
Combined, those leave the shape of the trouble clear. Contact does not do the harm — circulation does. Any tank with petrol in it is a fuel problem. Whatever a worn pump sheds travels on, borne by the fuel, into your injectors further along, which is why a pump that has worked on that petrol is where a mechanical issue begins.
Petrol in a diesel in The Coppice: how bad is it? Four situations
Fuelled up, not once started. The best case there can be. At a forecourt, and genuinely only there, that petrol is still limited to that tank — because everywhere else the vehicle was driven to get to it. The job is draining and rinsing on the spot.
Started for a moment, or just your ignition on. Petrol has left your tank and reached the filter and the lines, because the fuel system has been bled. Usually little more than clearing, flushing and sorting the fuel filter, and so still simple.
Those few miles driven were the pump labouring on fuel thinned by petrol throughout. How hard the vehicle was driven counts as much as how far, and this work takes in that tank, the lines, the filter and fresh fuel through the whole system. A school run to Hurst Hill Primary School is one thing. Any mileage on the M6, under 5 miles from The Coppice, means your engine working hard throughout, and a run to Wolverhampton, under 5 miles away, makes a very different job as well.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The fuel is not acting like diesel any more, and your engine is telling you. Stop wherever you are — the verge on Corfe Road, a lay-by, a side street — and leave it there. The fuel drain and flush still come first, and they sort it out: if a car is pulled over soon, lasting damage is very rare.
What The Coppice people get told about petrol in a diesel — and the myths in it
False: topping up to full with diesel makes it fine. It does not. Topping up takes out nothing; it gives you a bigger tank of the same mix. The idea behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
"Newer diesels can handle a little petrol" — a myth, and nearer the opposite. Finer components and higher pressure are the way a modern diesel runs its fuel, and that makes the protection count more, not less.
"It starts, it drives, so no harm done" — the myth that catches most drivers than any other. Feed diesel to a petrol motor and it generally will not run, so the driver stops — and the damage stops with them. Feed petrol to a diesel and it normally fires up, ticks over and drives away as if nothing has happened — all while its pump wears. Running does not mean fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, meant for another fault. What petrol has thinned stays weakened, and the petrol remains inside your tank anyway.
"Drain it yourself and you are sorted" — a myth, since after it has been running some petrol lies in your filter and lines, waiting to go straight back through the pump on the next start. And, a can of petrol filled at the kerbside is genuinely hazardous.
How does petrol in a diesel take place?
A careless moment is seldom the cause, and no one 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 vehicle at all. So the mistake runs one way.
It takes place when routine and your car stop matching. Courtesy car, hire car, or a motor that is brand new. A household with one petrol and one diesel on the drive. A forecourt you know, but with its pumps arranged differently. A train to catch, and a hurried fill en route to Coseley. A new-to-you diesel Volkswagen Passat, its first fuelling, and a driver accustomed to petrol: precisely when it occurs. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
The Coppice drivers: how to prevent petrol in a diesel next time
- The label is what matters, and so check the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- In a vehicle you don't know, look inside the flap over the filler or at the cap before your first fill: many motors state the fuel there.
- Good intentions count for less than a sticker or a fob in a bright colour on your diesel's key if a household has one of each. So label it.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump. It sounds silly and it does the trick.
- Whilst you are thinking about something else, this is an easy mistake to make — so put the phone away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to refuse a petrol nozzle, and aftermarket devices exist for the remainder. Treat it as a safety net, then keep checking the petrol pump.
- Stop as soon as you notice. Less petrol in your tank makes a weaker blend. It doesn't change what to do next, which is still not to crank it.
Petrol already in a diesel around The Coppice? Begin here
The order of things is short, then. Don't turn your ignition on, and do not fire it up. Yet on the forecourt, at BP or anywhere else? Ask the attendants to help you push the car clear of the pump. Next, 0333 366 0103. We'll ask what got in, roughly how much, and if it has been run.
Corrosion and deposits are the trouble with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and read its own The Coppice page.
One petrol in a diesel task around The Coppice costs more than another. Why?
Four different jobs sit behind the four situations above — which is why there is no honest single price. Mostly, your cost moves with which situation you are in. Next it is the ratio — how much petrol was put in against how much your tank holds — and then where the vehicle is and whether a technician can get to it safely.
Three questions come first, before any quote, instead of after — what was put in, how much, has it run — and that is the reason. With those answers, there is a straight figure rather than a range.
About The Coppice and where it is
The Coppice is a suburban area located near Wolverhampton in the West Midlands, sitting at an elevation of 187 metres. The Coppice is characterized by its predominantly semi-detached housing stock, which is typical of many suburban areas in the region. The Coppice is situated close to other nearby places, including Hurst Hill, Swan Village, and Roseville, and is approximately 3.4 miles from Wolverhampton city centre. The Coppice has a population of around 5791 residents.
Fuel drain cover across West Midlands, The Coppice included
Our teams answering petrol in diesel call-outs around The Coppice, in the WV postcode area, equally work the locations around it, Hurst Hill, Swan Village and Roseville among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations we work, and your car does not need to come to us.
At the petrol pump around The Coppice, right now?
No position is better: that is where you are. Ring, and keep it switched off.