Should You Worry? Petrol in a Diesel Car in Park Farm
Far less than you probably are, provided it hasn't been started. "Have I wrecked it?" is the first thing everyone around Park Farm asks, and the honest answer is normally no, because petrol left in a diesel tank harms nothing till it's drawn through the fuel system — by ignition priming, by the starter, or by driving. Leave your motor off and ring Petrol in Diesel — that is how you keep it like that. 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 a second time.
The engine and petrol in a diesel: what happens
Passing through a motor, diesel is doing two things at once. It burns, and before it burns it lubricates. Very fine gaps go into the injectors and the high-pressure fuel pump, and only the diesel running through keeps their surfaces from grinding together.
Badly at the first, not at all at the second: that is petrol. It is runnier than diesel and takes away the lubrication the system hinges on, and so a pump running on a petrol blend is a pump wearing itself. And petrol is made to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the knocking comes from.
Seen together, they make clear the shape the problem has. Contact does not do the damage — movement does. Petrol in a tank is a fuel fault. 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 your injectors downstream.
Park Farm, petrol in a diesel: four cases, from mild to significant
Fuelled up, not once started. The best case there is. Only the tank has petrol in it, and so the task is emptying the tank and cleaning your system where your car sits. This situation can only truly occur on a forecourt: anywhere else, the vehicle got there by being driven.
Your ignition turned on, or a short start. The fuel system has been bled, so petrol has left that tank and got to the fuel filter and the fuel lines. Normally nothing more than emptying, flushing and sorting the fuel filter, so still simple.
A couple of miles driven, and your pump has spent every one of them working on thinned fuel. The work is the tank, the fuel lines, the filter and fresh fuel through the entire circuit, and how hard the vehicle was driven matters as much as how far. Driving the kids to the local primary school is one sort of trip. Any distance on the M8, under 5 miles from Park Farm, means your engine has worked hard throughout, and a run to Glasgow, under 25 miles away, is a very different job too.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone uneven. The engine is telling you your fuel is no longer behaving like diesel. Whether it is the verge on Mansion Avenue, a lay-by or a side road, stop where you are and leave it. Lasting damage is very unusual if a car is stopped early, and the fuel drain and flush that still go first deal with it.
What Park Farm people get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mix. The idea behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the reverse is true. Myth: "A newer diesel can cope with a bit of petrol." Lubrication matters more on modern diesels, not less, since their fuel passes through more precise components at higher pressure.
One myth that catches people off guard: if it starts and drives, it must be unharmed. A petrol engine fed diesel usually will not run, so the motorist stops and the harm stops with them. A diesel fed petrol generally starts, idles and drives away as if nothing has happened, whilst the pump wears. Being able to run isn't proof of being fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an outdated workaround for a different fault. It doesn't put back what petrol has weakened, and that petrol is still in that tank after that.
If your engine has run, part of the petrol is in your filter and the fuel lines, not the tank — and the next start pulls it straight back through the pump. So the myth "drain that tank yourself and you're sorted" doesn't hold. Besides, petrol cleared into a can by the road is genuinely dangerous.
Petrol in a diesel: how does it occur?
It's seldom carelessness, and nobody does it on purpose. The forecourt makes it easy: the petrol nozzle is the slimmer of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally will not go into a petrol vehicle at all. So the mistake runs one way.
The moment habit stops matching the car is the moment it occurs. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps laid out differently. Filling up in a hurry en route to Woodhall, with a train to catch. A new-to-you diesel Volkswagen Passat, its first fuelling, and a driver accustomed to petrol: exactly when it happens. Your hand does what it has always done when you add rain, a phone call or a back seat full of children.
Avoiding petrol in a diesel next time you fill up in Park Farm
- A green handle for unleaded and black for diesel is usual in the UK — yet not on every forecourt. Trust the label on the pump, not the colour.
- In a vehicle you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of cars state the fuel type there.
- Label the key. In a house with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump. It seems daft and it does the trick.
- While you are thinking about something else, this is an easy mistake to make — so put the phone away.
- Some diesels have a filler designed to block a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- Noticing it mid-fill? Stop at once. A weaker mixture follows from less petrol in your tank, yet your next step remains the same: do not start it.
Park Farm: already put petrol in a diesel?
Short and simple, then, is the order of things. Do not crank it, and don't switch your ignition on. The staff at the forecourt — whether at Tesco itself or wherever you filled up — will usually help roll it clear of the petrol pump if you ask. What was put in, roughly how much, and whether it has run: tell us those when you phone 0333 366 0103.
Say so if it was AdBlue rather than petrol: it's a different problem, with its own page for Park Farm, because AdBlue brings corrosion and deposits instead of lost protection.
One petrol in a diesel job in Park Farm costs more than another. Why?
There's no fair single price for this, since the four scenarios above are four separate tasks. The situation itself does most of the work of moving your cost. Where your car is counts too, and whether a van can safely reach it, after the share of petrol to what your tank holds.
That's why we ask three questions before pricing rather than after: what went in, how much, and if it has run. Their answers are what turn a range into one firm number.
About Park Farm
Park Farm is a suburban area located on the coast of Inverclyde, with a mix of semi-detached housing and other residential properties. Park Farm sits at an elevation of 63 metres, overlooking the surrounding coastline and nearby communities such as Parkhill and Woodhall. Park Farm is situated near Glasgow, Scotland's largest city, and is part of the wider Glasgow urban area. Park Farm has a population of approximately 3396 residents, living in a variety of housing types, predominantly semi-detached homes.
Fuel drain cover across Inverclyde, Park Farm included
Petrol in diesel jobs around Park Farm — part of the PA postcode area — go to teams that also cover the places round it, Parkhill, Woodhall and Broadfield among them. No need to bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
Park Farm: still at the petrol pump?
In that case, you couldn't be in a better spot. Switched off it stays; then call.