Petrol in a Diesel Car in Green End: How Worried Should You Be?
Not started? Then less worried than you probably are. Until the ignition primes your pump, your starter turns, or your car is driven, petrol in a diesel tank just waits there and does no harm. Which means the honest reply to the first Green End query — "have I ruined it?" — normally no. To leave the car like that, ring Petrol in Diesel then leave the motor alone. Below, you will find what petrol really does inside a diesel, how far it may have got, and how to stop it happening to you again.
What petrol in a diesel does to your engine
Diesel does two tasks on its way through an engine. Lubricating comes before burning; it does both. Very fine tolerances go into the injectors and the high-pressure fuel pump, and only your diesel flowing through keeps those surfaces from grinding together.
Of these two tasks, petrol handles the first poorly and the second not at all. The knocking 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 out the protection the fuel system hinges on, and any pump working on that blend is wearing itself.
The shape of the trouble is clear once you put those together. It's movement that does the damage, not contact. Any tank with petrol in it is a fuel fault. Once the pump has been labouring on that petrol, a mechanical problem has begun: whatever is shed by a pump that's wearing travels onward to the injectors with the fuel.
How serious is petrol in a diesel? Four scenarios we see in Green End
The best case there can be: filled up, never started. The petrol is inside the tank and only that tank, and the task is a drain and a flush where the car sits. This is the one scenario that can only really take place at a forecourt, because anywhere else the car has been driven to get there.
A moment's running, or merely your ignition on. Petrol has left the tank and got to the fuel filter and the lines, since the fuel system has been primed. Drain, flush, see to your filter: still usually straightforward.
Driven a few miles. Now your pump has spent these miles labouring on diluted fuel. The work is the tank, the fuel lines, the fuel filter and fresh fuel through the whole circuit, and how hard your car was driven counts as much as how far. A school run to Oakleaf Primary is one matter. Any distance on the M1, under 5 miles from Green End, means your engine working hard throughout, and a run to St Albans, under 10 miles away, makes a very different task as well.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone lumpy. The fuel is not acting like diesel any more, and your motor is telling you. Pull up where you are — on the verge on Northridge Way, at the kerb, down a side road — and do not move it again. Lasting damage is very unusual when a car is stopped quickly, and the fuel drain and flush that still come first sort it out.
Petrol in a diesel myths Green End motorists hear
False: topping up to full with diesel makes it fine. It doesn't. A fuller tank of the same mix is all it gives, since topping up removes nothing. That guidance supposes a diesel fuel system handles petrol by percentage. It does not.
"Modern diesels can handle a little petrol" — a myth, and closer to the reverse. At higher pressure, through more precise parts: that is how a current diesel moves its fuel, and so the protection matters more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches drivers. The driver of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the harm stops there. Whilst your pump grinds, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. A running engine does not mean fine.
Myth: a two-stroke additive makes it safe to drive home. It was an old workaround, supposed for another fault. None of what petrol thinned gets put back by it — and later, that tank still contains that petrol.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol lies in the fuel filter and lines, ready to go straight back through the pump on the next start. On top of that, petrol emptied into a can by the road is truly dangerous.
Why petrol in a diesel happens so easily
On purpose? Never. Through carelessness? Seldom, if ever. The forecourt makes it simple: the petrol nozzle is the narrower 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.
Habit and the vehicle getting out of step is how it occurs. Hire cars, courtesy cars, and vehicles that are new to you. Two motors on one drive, one petrol, one diesel. The pumps in a different order on a familiar forecourt. A rushed fill en route to Hemel Hempstead with a train to catch. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Passat for the first time. With rain, a call coming in, or children to deal with, the hand just does what it has always done.
How to avoid petrol in a diesel on your next fill-up in Green End
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most usually do. Read the pump's label; the colour is only a hint.
- Inspect the filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on the first fill in any car you don't know.
- One of each in the house? Label the key to your diesel — a coloured fob, a sticker — because intending to remember is not enough.
- Before the nozzle comes off the petrol pump the first time you fill a hired or new vehicle, say "diesel" out loud. Silly, perhaps, but it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck the phone away then keep your mind on the petrol 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 are available for cars without one. They are a safety net, not a reason to stop checking the petrol pump.
- Stop as soon as you notice. Less petrol inside that tank means a thinner mixture. It does not change what to do next, which is still not to start it.
Put petrol in a diesel around Green End already?
The order of things is short, then. Starting it is out, and so is switching on the ignition. The staff on the forecourt — whether at Shell itself or wherever you filled up — will normally help roll it away from the pump if you ask. Next, 0333 366 0103. We will ask what was put in, about how much, and if it has been run.
Say so if it was AdBlue rather than petrol: it's a different fault, with its own page for Green End, because AdBlue brings corrosion and deposits rather than lost lubrication.
Why one petrol in a diesel task around Green End costs more than another
The four situations above are four different tasks, so no single quote for this would be fair. The scenario itself does most of the work of moving your cost. Two things come after that: the petrol that got in as a share of what your tank holds, then the spot the vehicle is in and whether a van can reach it safely.
Three queries come first, before quoting, rather than after — what got in, how much, has it run — and that is the reason. The answers change a range into a straight figure.
About Green End, for a moment
Green End is a suburban area in Hertfordshire, situated near the River Ver and close to the city of St Albans. Green End has a mix of housing types, but is predominantly made up of terraced homes, and is located about 6.7 miles from St Albans. Green End sits at an elevation of around 103 metres, and is part of the wider commuter belt around London, which is approximately 23 miles away. Green End is near other local places such as Chaulden and Boxmoor.
Fuel drain cover across Hertfordshire, Green End included
Our vans answering petrol in diesel call-outs in Green End, in the HP postcode area, equally work the spots around it, Chaulden, Counters End and Boxmoor included. No need to move your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
Green End: still at the petrol pump?
The best position there is, then — that is where you are. Keep it switched off, then ring.