Should You Worry? Petrol in a Diesel Car in Field Head
Unstarted? Then less anxious than you probably feel. Everyone around Field Head starts with "have I wrecked it?", and the honest answer is usually no: petrol resting inside your tank of any diesel stays harmless until priming, cranking or driving draws it into the fuel system. Keep it like that: leave your engine off and phone Petrol in Diesel. The rest of this page covers what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Your engine and petrol in a diesel: what goes on
Two tasks fall to diesel on its journey through a motor. It lubricates to begin with, and only then does it burn. Designed to very fine gaps, the fuel injectors and your pump rely on the diesel flowing through them to stop their surfaces wearing against one another.
Badly at the first, not at all at the second: that is petrol. A pump running on a petrol blend is wearing itself out, since petrol is runnier than diesel and strips out the lubrication the fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where any clattering comes.
Put these together and the shape of the problem is clear. The damage is done by circulation, not by contact. Any tank with petrol in it is a fuel problem. A pump that has been working on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with your fuel to your injectors further on.
Four situations we see around Field Head: how bad is petrol in a diesel?
Filled up, and not started: nothing beats it. On a forecourt, and really only there, that petrol is still limited to your tank — because everywhere else the vehicle was driven to reach it. The job is emptying and flushing on the spot.
A brief spell of running, or merely your ignition on. Once primed, your system has pulled petrol out of your tank as far as your filter and the lines. Drain, flush, deal with the filter: still usually simple.
The pump has worked a few miles on diluted fuel — that's what driving the car meant. Mileage is only half of that; how hard it was driven counts equally. Either way this work runs to the tank, the lines, the filter and fresh fuel through the entire circuit. On the school run to Mercenfeld Primary School, the mileage is small. Very different once more: a trip to Leicester, under 10 miles away, or any miles on the M1, under 3 miles from Field Head, where the motor kept running hard.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone ragged. What you are hearing is the motor reporting fuel that no longer behaves like diesel. Stop on the spot — on the verge on Charnwood Drive, at the kerb, down a side road — and do not move it again. Lasting damage is very rare when a vehicle is pulled over soon, and the fuel drain and flush-through that still come first sort it out.
What Field Head motorists get told about petrol in a diesel — and the myths in it
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A bigger tank of the same mix is all you get, because topping up takes out nothing. That advice supposes a diesel fuel system tolerates petrol by percentage. It does not.
Not so: a current diesel copes with a bit of petrol. Rather, the opposite. A modern diesel runs its fuel through finer components at higher pressure, which makes the protection matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no harm done." Diesel in a petrol motor generally means a motor that will not run: the motorist stops, and so does the damage. Whilst the pump wears, a diesel fed petrol usually starts, idles and drives away as though nothing has happened. Running does not mean fine.
Myth: a two-stroke additive makes it safe to drive home. It is an old fix, meant for another problem. The petrol is still in the tank after that, and whatever it has weakened isn't put back.
Once the engine has run, part of that petrol sits in your filter and the fuel lines, not the tank — and the next start pulls it straight back through your pump. So the myth "drain your tank yourself and you are sorted" does not stand up. Draining petrol into a can at the roadside is also genuinely dangerous.
How does petrol in a diesel happen?
Carelessness is seldom the cause, and nobody means to do it. The forecourt makes it simple: the petrol nozzle is the slimmer of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle mostly will not go into a petrol car at all. So the mistake runs one way.
When routine and the vehicle stop matching, it takes place. A new car, a hire car or a courtesy car. Two cars on one drive, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. A rushed fill on the way to Barrow Upon Soar 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. Throw in rain, a phone call or a back seat full of kids, and the hand repeats what it has always done.
Field Head 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 every forecourt. Trust the label on the petrol pump, not the colour.
- The first fill in a new motor is the time to check your filler flap — on it, or on the cap, plenty of motors 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 when a household has one of each. So label it.
- It seems silly and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump.
- While you're thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to reject a petrol nozzle, and aftermarket devices are available for the remainder. Treat it as a backstop, then keep checking the pump.
- Stop the moment you notice. Less petrol in the tank makes a weaker mix. It does not change what to do next, which is still not to start the car.
Put petrol in a diesel in Field Head already?
Then, there is only a short order of things. Starting it is out, and so is turning on your ignition. If you're still on the forecourt — BP or anywhere else — ask the attendants to help you roll it away from the petrol pump. Next, 0333 366 0103. We will ask what got in, roughly how much, and if it's been run.
If it was AdBlue instead of petrol, say so. That's a separate fault — corrosion and deposits rather than lost protection — and it has its own page for Field Head.
Why one petrol in a diesel job around Field Head costs more than another
The four situations above are four separate jobs, so no single price for this would be honest. The scenario itself does most of the work of moving the cost. After that it's the ratio — how much petrol got in against how much the tank holds — and then where the vehicle is and whether our van can reach it safely.
Three queries come first, before quoting, instead of after — what went in, how much, has it run — and this is the reason. The replies turn a range into a straight figure.
About Field Head, briefly
Field Head is a suburban area in Leicestershire, situated approximately 6.4 miles northwest of Leicester. Field Head sits at an elevation of 177 metres, in a gently rolling landscape of inland East Midlands. Field Head is characterised by its predominantly detached housing stock, with nearby places including Markfield, Newtown Linford, and Bondman Hays. Field Head is home to a population of around 1779 residents, who are within easy reach of Leicester's amenities.
Fuel drain cover across Leicestershire, Field Head included
Field Head sits in the LE postcode area, and the teams that answer petrol in diesel calls there work the spots around it as well — Markfield, Newtown Linford and Bondman Hays among them. You need not bring your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
In Field Head and still at the pump?
No position is better: that's where you now are. Keep the vehicle switched off, then ring.