Petrol in a Diesel Car in Silver Street: How Worried Should You Be?
Probably less than you already are — provided nobody has started it. "Have I ruined it?" is the first question anyone in Silver Street asks, and the truthful answer is usually no, because petrol left in a diesel tank harms nothing till it is dragged through the system — by ignition priming, by your starter, or by driving. Leave the engine off and phone Petrol in Diesel — that is how you keep it that way. The rest of this page sets out what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you a second time.
Inside your engine: what petrol in a diesel does
Two tasks fall to diesel on its route round a motor. Oiling comes before burning; it does both. What stops the surfaces inside the high-pressure fuel pump and the injectors from wearing against each other is your diesel passing through them — they're built to very fine tolerances.
Of these two jobs, petrol handles the first poorly and the second not at all. It is thinner than diesel and strips away the protection your fuel system depends on, so a pump running on a petrol mixture is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the clattering comes from.
Taken together, they show the shape the trouble takes. It is movement that causes the harm, not contact. A tank with petrol in it is a fuel fault. A pump that has been labouring on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the injectors downstream.
How serious is petrol in a diesel? Four scenarios our technicians see around Silver Street
Filled up, not once started. The best case there can be. Just your tank has petrol in it, so the job is draining that tank and rinsing your system where the vehicle stands. This situation can only truly take place on a forecourt: anywhere else, the car got there by being driven.
Your ignition switched on, or a brief start. Once primed, the system has drawn petrol out of the tank as far as the filter and the fuel lines. Usually little more than clearing, cleaning and sorting your filter, so still simple.
Driven a couple of miles. Now your pump has spent those miles working on weakened fuel. Tank, lines, filter, then fresh fuel run through the entire circuit: that's this work, and the way the vehicle was driven counts as much as the distance. Short trips, such as the school run to Bredgar Church of England Primary School, are one matter. Getting as far as Southend-on-Sea, under 25 miles away, makes a very different task — as does any mileage on the M2, under a mile from Silver Street, with the motor running hard the whole time.
Clattering, an uneven idle, smoke, a throttle gone soft: driven till it complained. That is the motor telling you its fuel has stopped acting like diesel. Whether it's the verge on Gore Road, a lay-by or a side road, stop there and leave it. Lasting damage is very unusual if a vehicle is stopped soon, and the drain and flush-through that still go first sort it out.
Silver Street drivers and the petrol in a diesel stories they 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 bigger tank, still the same mixture. The idea behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Modern diesels can handle a little petrol" — a myth, and closer to the opposite. At higher pressure, through smaller parts: that's how a modern diesel handles its fuel, so the lubrication matters for more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools drivers. Feed diesel to a petrol motor and it usually will not run, so the motorist stops — and the harm stops with them. Whilst the pump grinds, a diesel fed petrol normally starts, ticks over and drives away as though nothing has happened. Running is not the same as fine.
An outdated fix for a separate fault lies behind this one. Myth: "Add some two-stroke oil and drive the car home." None of what petrol weakened gets put back by it — and afterwards, the tank still contains the petrol.
The next start draws petrol back round your pump from the lines and your filter, where some of it ends up after the motor has been run. That is why draining the tank yourself does not sort it — a myth. Clearing petrol into a can by the kerbside is also genuinely hazardous.
Petrol in a diesel: how does it occur?
Carelessness is seldom the cause, and no one means to do it. One way only, since of the nozzles: the smaller petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol motor. That's how the forecourt makes it simple.
The moment habit stops matching the car is the moment it happens. Hire cars, courtesy cars, and motors 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. A train to catch, and a hurried fill en route to Sittingbourne. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that is when. Add rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Next time you fill up in Silver Street: avoiding petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Read the pump's label; the colour is only a hint.
- The first fill in a strange vehicle is the time to check the filler flap — inside it, or on the cap, many vehicles state the fuel to use.
- 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.
- Before the nozzle leaves the pump the first time you fill a hired or new motor, say "diesel" aloud. Silly, perhaps, but it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away then keep your mind on the pump.
- Add-on devices are available for motors without one, and some diesels are built with a filler that will not take a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label.
- Less petrol makes a weaker mixture, so stop the moment you realise — while remembering that the next stage is unchanged. It's still not to crank it.
Already put petrol in a diesel in Silver Street?
Then, there's only a short order of things. Starting it is out, and so is switching on the ignition. If you're still on the forecourt — Texaco or anywhere else — ask the staff to help you roll the car clear of the petrol pump. Next, 0333 366 0103. We will ask what went in, roughly how much, and if it has been run.
Corrosion and deposits form the issue with AdBlue, whereas petrol brings lost lubrication. So if it was AdBlue, say so — and see its own Silver Street page.
Silver Street petrol in a diesel jobs: why one costs more than another
The four scenarios above are four separate tasks, so no single quote for this would be honest. Chiefly, the cost moves with which one you are in. Two things come after that: the petrol that went in as a share of what your tank holds, then the place the car is in and whether a technician can reach it safely.
Three questions come first, before any quote, rather than after — what was put in, how much, has it run — and that is the reason. With those answers, you get a straight figure rather than a range.
About Silver Street, briefly
Silver Street is a small hamlet in Kent, situated inland at an elevation of 86 metres, and is located near the villages of Bredgar and Stiff Street. Silver Street comprises predominantly detached housing and is home to a population of around 682 residents. Silver Street is positioned approximately 37.9 miles from London and 15.7 miles from the city of Southend-on-Sea, in the South East region of England. Silver Street sits in a rural area, close to Deans Hill and other nearby settlements.
Silver Street and Kent: where our fuel drain cover runs
Petrol in diesel call-outs around Silver Street — part of the ME postcode area — go to teams that also cover the locations round it, Bredgar, Stiff Street and Deans Hill included. The vehicle doesn't need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the pump around Silver Street, still?
Nothing beats it: that's where you are. Phone, and leave it switched off.