How Worried Should You Be? Petrol in a Diesel Car in Blackfords
Provided it has not been started, worry less than you probably are. Until the ignition primes your pump, your starter cranks, or your vehicle is driven, petrol in a diesel tank simply sits there and does no harm. Which means the truthful reply to the first Blackfords query — "have I ruined it?" — usually no. To leave it that way, call Petrol in Diesel then leave your motor switched off. What petrol actually does to a diesel, how to judge how far it has travelled, and how to stop it from happening again: that is the rest of this page.
Petrol in a diesel: what does it do to the engine?
Two tasks fall to diesel on its route round a motor. Oiling comes before burning; it does both. Extremely fine tolerances go into the injectors and your high-pressure pump, and only your diesel flowing through keeps those surfaces from grinding together.
The second task petrol doesn't do at all, and the first it does badly. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection the fuel system depends on, and any pump working on such a blend is wearing itself.
Seen together, they show the shape the trouble has. Not contact but movement is what does the harm. Petrol in a tank is a fuel problem. The beginning of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to the injectors beyond it.
How bad is petrol in a diesel? Four situations our engineers see around Blackfords
Filled up, and not started: nothing beats it. Only the tank has petrol in it, so the task is draining your tank and cleaning the system where the car sits. This situation can only really happen on a forecourt: anywhere else, the car got there by being driven.
A brief spell of running, or merely your ignition on. Petrol has left your tank and got to the fuel filter and the fuel lines, because the fuel system has been bled. Still usually simple: drain, flush, and the fuel filter dealt with.
Driven a couple of miles. Now your pump has spent those miles working on weakened fuel. Miles is only half of that; how hard it was driven matters just as much. Either way this work includes that tank, the lines, your filter and fresh fuel through the whole circuit. On the school run to Chadsmoor CofE (VC) Junior School, the mileage is small. A run as far as Lichfield, under 10 miles away, is a very different task. So is any mileage on the M6 Toll, under 3 miles from Blackfords, where the engine has been working hard the whole time.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you your fuel is no longer acting like diesel. Pull up wherever you are — the verge on Short Street, a lay-by, a side street — and leave it there. Permanent damage is very uncommon if a vehicle is stopped soon, and the fuel drain and flush-through that still come first deal with it.
Blackfords people and that petrol in a diesel myths they hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing is removed by topping up — you're left with a fuller tank, still the same mixture. A diesel fuel system does not tolerate petrol by percentage in the way that guidance assumes.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." A modern diesel runs its fuel through smaller parts at higher pressure, which makes the protection matter more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools people. Any petrol engine fed diesel generally will not run, so the driver stops and the damage stops with them. Whilst your pump grinds, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. A running engine doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different issue. It does not put back what petrol has thinned, and the petrol is still in your tank afterwards.
Myth: "Drain that tank yourself and you're sorted." After your engine has been run, some of the petrol is no longer in the tank: it is in the fuel filter and the lines, and it goes straight back through your pump at the next start. It is also genuinely hazardous to drain petrol into a can at the roadside.
Why petrol in a diesel takes place so easily
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle generally won't go into a petrol vehicle, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and only in one direction.
When habit and your car stop matching, it happens. A motor that is new to you — hired, on loan as a courtesy car, or just bought. Two motors on one drive, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. Fuelling up in a rush en route to Cannock, with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. With rain, a call arriving, or a car full of children to deal with, the hand just does what it has always done.
Blackfords people: how to prevent petrol in a diesel next time
- Green for unleaded and black for diesel is usual in the UK — yet not on each forecourt. Go by the label on the petrol pump, not the colour.
- Check your filler flap. Plenty of vehicles state the fuel type inside the flap or on the cap. Look at it on your first fill in any vehicle you don't know.
- Mark the key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- 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.
- Mistakes like this are easy to make whilst your mind is on something else, so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to reject a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop reading the petrol pump.
- Less petrol means a thinner mixture, so stop as soon as you notice — while remembering that your next step is unchanged. It is still not to crank it.
Already put petrol in a diesel around Blackfords?
Then, there's just a short order of things. Don't switch your ignition on, and don't fire it up. Yet at the forecourt, at the nearest petrol station or anywhere else? Ask the attendants to help you push it away from the pump. What got in, roughly how much, and if it's run: tell us that when you ring 0333 366 0103.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate problem — Blackfords has a page just for it.
One petrol in a diesel task in Blackfords costs more than another. Why?
There is no fair single quote for this, because the four scenarios above are four different jobs. Which of them you're in is mostly what moves your cost. Where the car is matters too, and whether a technician can safely get to it, after the ratio of petrol to what the tank takes.
Three queries come first, before any quote, instead of after — what was put in, how much, has it run — and this is the reason. A range turns into a straight figure when those replies are in.
About Blackfords itself
Blackfords is a suburban area in Staffordshire, situated near the city of Lichfield and overlooking the surrounding riverside landscape. Blackfords sits at an elevation of 162 metres, with semi-detached housing being the predominant type of accommodation in the area. Blackfords is located near other nearby places such as Broomhill, Oldfallow, and Chadsmoor, and is approximately 115 miles from London. Blackfords has a population of around 6552 residents.
Fuel drain cover across Staffordshire, Blackfords included
The teams answering petrol in diesel calls around Blackfords, in the WS postcode area, also work the places around it, Broomhill, Oldfallow and Chadsmoor among them. The vehicle 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 drive.
Blackfords: still at the pump?
Nothing beats it: that is where you now are. Leave the car turned off, then ring.