Should You Worry? Petrol in a Diesel Car in St Pancras
Less than you likely are, provided it hasn't been started. "Have I wrecked it?" is the first question everyone in St Pancras asks, and the honest answer is generally no, because petrol resting in a diesel tank harms nothing till it is dragged through your fuel system — by ignition priming, by your starter, or by being driven. Keep it that way: leave the motor off then phone Petrol in Diesel. What petrol really does to a diesel, how to judge how far it has travelled, and how to stop it from happening again: that's the remainder of this page.
Petrol in a diesel: what does it do to the motor?
On its way through a motor, diesel has two jobs. It ignites, and before it combusts it lubricates. Extremely fine gaps are built into your injectors and the high-pressure pump, and just the diesel flowing through keeps those surfaces from grinding together.
The second task petrol doesn't do at all, and the first it does poorly. The rattling comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection your system hinges on, and any pump running on that blend is wearing itself.
Taken together, they show what shape the problem takes. It is circulation that causes the damage, not contact. Any tank with petrol in it is a fuel problem. 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 your injectors further on.
Petrol in a diesel in St Pancras: how bad is it? Four situations
The best case there is: filled up, never started. Only the tank has petrol in it, and so the job is clearing that tank and rinsing your system where the car stands. This situation can only truly occur on a forecourt: anywhere else, the vehicle got there by being driven.
The ignition turned on, or a short start. Your system has been primed, and so petrol has left the tank and reached the filter and the fuel lines. Normally nothing more than emptying, flushing and sorting your filter, and so still straightforward.
Those few miles on the road were the pump labouring on fuel thinned by petrol the whole way. The work is that tank, the lines, your filter and clean fuel through the whole circuit, and how hard your car was driven matters as much as how far. Driving the children to Edith Neville Primary School is one sort of trip. A run as far as London, under 3 miles away, is a very different job. So is any miles on the M1, under 10 miles from St Pancras, where the motor has been working hard the whole time.
Driven until it complained. Rattling, a lumpy idle, smoke, a throttle that has gone soft. What you are hearing is the motor reporting fuel that no longer acts like diesel. Pull up wherever you are — the verge on Goods Way, a lay-by, a side street — and leave it there. Lasting damage is very unusual when a vehicle is stopped quickly, and the drain and flush that still come first deal with it.
St Pancras motorists and that petrol in a diesel stories they hear
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A bigger tank of the same mixture is all it gives, because topping up takes out nothing. That guidance supposes a diesel fuel system tolerates petrol by percentage. It doesn't.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the reverse. Smaller parts and higher pressure are the way a modern diesel runs its fuel, and that makes the lubrication matter more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools people. The driver of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the damage stops with them. While the pump wears, a diesel fed petrol normally starts, ticks over and drives away as though nothing has happened. Running is not the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It was an old fix, meant for another issue. What petrol has diluted remains weakened, and the petrol remains inside that tank regardless.
If the motor has run, part of the petrol sits in your filter and the fuel lines, not that tank — and the next start pulls it straight back through your pump. So the myth "drain your tank yourself and you're sorted" doesn't stand up. It is also really hazardous to drain petrol into a can at the roadside.
How it happens: petrol in a diesel
A careless moment is seldom the cause, and no one means to do it. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one generally won't fit a petrol vehicle. That's how the forecourt makes it straightforward.
When habit and the vehicle stop matching, it happens. Any car that is new to you — hired, on loan as a courtesy car, or brand new. One petrol and one diesel on the driveway of the same household. A forecourt you know, only with its pumps arranged differently. Filling up in a hurry on the way to London St Pancras International, with a train to catch. Exactly the moment it occurs: after years of driving petrol, someone fills a diesel Renault Megane for the first time. The hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
Next time you fill up around St Pancras: avoiding petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, yet not on each forecourt. The label is what matters.
- Inspect your filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on your first fill in any motor you don't know.
- Good intentions count for less than a sticker or a fob in a bright colour on your diesel's key if a home has one of each. So mark it.
- "Diesel", out loud, before you lift the nozzle — each time a new or hired car needs its first tank. It sounds silly. It works.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away then keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to block a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop checking the pump.
- Spotting it halfway? Stop there and then. A thinner blend results from less petrol inside the tank, yet your next step stays the same: do not fire it up.
Petrol already in a diesel in St Pancras? Begin here
Then the order of things is short. Don't switch your ignition on, and don't fire it up. The attendants on the forecourt — whether at Texaco itself or wherever you filled up — will normally help push it clear of the pump if you ask. Then call 0333 366 0103 and tell us what was put in, roughly how much, and whether it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different fault — St Pancras has a page all for it.
What makes one St Pancras petrol in a diesel task cost more than the next
A fair single price does not exist here: four scenarios, four separate tasks. The situation itself does most of the work of moving the cost. Two things come after that: the petrol that got in as a proportion of what the tank holds, then the place the vehicle is in and whether our van can get to it safely.
Three queries come first, before quoting, rather than after — what was put in, how much, has it run — and that is the reason. Those replies are what change a range into one firm number.
About St Pancras
St Pancras is a suburban area in central London, situated near the Regent's Canal and the River Thames, with a mix of old and new buildings. St Pancras sits at a relatively low elevation of 19 metres above sea level, close to the city centre and neighbouring areas like Kings Cross and Somers Town. St Pancras is predominantly composed of flat dwellings, reflecting its urban character. St Pancras is home to a diverse population of around 17,167 people, living in a variety of housing types.
Across Greater London and in St Pancras: fuel drain cover
Petrol in diesel calls around St Pancras — part of the N1C postcode area — go to vans that also cover the spots round it, Kings Cross, Somers Town and Pentonville among them. A forecourt, a supermarket car park, a lay-by or your own drive are all locations our engineers work, and your vehicle doesn't need to come to us.
Still at the pump in St Pancras?
Nothing beats it: that is where you are. Keep it off. Phone.