How Worried Should You Be? Petrol in a Diesel Car in Capel
Probably less than you are now — as long as nobody has started it. Petrol resting in a diesel tank does nothing to the motor till something pulls it through the fuel system — your ignition priming your pump, your starter, or driving itself. So the honest answer to the first query everyone around Capel asks, "have I ruined it?", is usually no. To leave the car like that, call Petrol in Diesel and leave the engine alone. What petrol actually does to a diesel, how to gauge how far it's gone, and how to keep it from happening a second time: that's the rest of this page.
Inside your engine: what petrol in a diesel really does
Two jobs fall to diesel on its journey round a motor. Oiling comes before burning; it does both. Very fine clearances are built into the injectors and the high-pressure pump, and just your diesel flowing through stops those surfaces grinding together.
Of these two jobs, petrol manages the first poorly and the second never. A pump running on a petrol mix is wearing itself out, since petrol is thinner than diesel and strips out the protection the fuel system depends 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.
Together, those make the shape of the issue plain. Contact doesn't do the damage — circulation does. Any tank with petrol in it is a fuel fault. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the fuel injectors downstream.
Capel, petrol in a diesel: four cases, from mild to major
Fuelled up, not once started. The best case there can be. Only your tank has petrol in it, so the task is draining your tank and flushing the fuel system where the car stands. This situation can only truly occur at a forecourt: anywhere else, your car got there by being driven.
Started for a moment, or just the ignition on. Once primed, your system has drawn petrol from your tank up to the fuel filter and the fuel lines. Drain, flush, deal with the filter: still normally simple.
Those few miles driven were your pump running on fuel weakened by petrol the whole way. How hard the vehicle was driven counts as much as how far, and the work covers that tank, the fuel lines, the filter and fresh fuel through the entire system. Driving the kids to Scott-Broadwood CofE Infant School is one sort of trip. Any mileage on the M23, under 10 miles from Capel, means the engine has worked hard throughout, and a run to Brighton and Hove, under 25 miles away, is a very different task too.
It protested, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone uneven. What you are hearing is the engine signalling fuel that no longer acts like diesel. Whether it's the verge on Vicarage Lane, a lay-by or a side street, stop where you are then leave it. Lasting damage is very unusual if a vehicle is pulled over early, and the fuel drain and flush that still come first take care of it.
What Capel motorists get told about petrol in a diesel — and the stories in it
Myth: topping up to full with diesel makes it fine. It doesn't. Topping up removes nothing; it gives you a bigger tank of the same mix. Percentage is not how a diesel fuel system tolerates petrol, however much that guidance assumes.
"Newer diesels can handle a little petrol" — a myth, and nearer the reverse. A current diesel runs its fuel through finer parts at higher pressure, which makes the lubrication matter more, not less.
"It starts, it drives, so no harm done" — the myth that catches more motorists than any other. Diesel in a petrol motor generally leaves a motor that won't run: the motorist stops, and so does the harm. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, whilst your pump wears. Being able to run is not the same as being fine.
An outdated workaround for a separate issue lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." The petrol is still inside the tank afterwards, and what it has thinned isn't put back.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol lies in the filter and lines, ready to go straight back through your pump on your next start. It's also genuinely hazardous to drain petrol into a can at the kerbside.
Why petrol in a diesel happens so easily
No one does it on purpose, and it's seldom carelessness. A diesel nozzle generally won't go into a petrol vehicle, but the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error easy, and only in that direction.
When habit and the car stop matching, it happens. A vehicle that is new to you — hired, on loan as a courtesy car, or brand new. Two cars on one driveway, one petrol, one diesel. The pumps in a different order on a well-known forecourt. Filling up in a rush en route to Ockley, with a train to catch. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. Throw in a back seat full of children, a phone call or rain, and the hand takes over.
Avoiding petrol in a diesel next time you fill up in Capel
- Green for unleaded and black for diesel is normal in the UK — but not on every forecourt. Trust the label on the pump, not the colour.
- The first fill in an unfamiliar vehicle is the time to check your filler flap — on it, or on the cap, many cars state the fuel they take.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key when a household has one of each. So label it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump. It seems daft and it works.
- While you are thinking about something else, this is an easy mistake to make — so put the phone away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to block a petrol nozzle, and aftermarket devices exist for the remainder. Treat it as a backstop, then keep reading the petrol pump.
- Stop the moment you notice. Less petrol in that tank means a thinner blend. It doesn't change what to do next, which is still not to start it.
Put petrol in a diesel in Capel already?
The order of things is brief, then. Never fire it up, and don't turn the ignition on. If you're still at the forecourt — Murco or anywhere else — ask the attendants to help you roll the vehicle clear of the petrol pump. What got in, about how much, and whether it has run: tell us those when you call 0333 366 0103.
If it was AdBlue and not petrol, say so. That is a different issue — corrosion and deposits and not lost lubrication — and it has its own page for Capel.
Why one petrol in a diesel job in Capel costs more than another
Four separate jobs sit behind the four scenarios above — which is why there's no honest single quote. The situation itself does most of the work of moving your cost. Next it is the ratio — how much petrol was put in against how much the tank holds — and after that where the vehicle is and whether our van can reach it safely.
Three queries come first, before quoting, instead of after — what got in, how much, has it run — and this is the reason. With those answers, you get a straight figure instead of a range.
About Capel, for a moment
Capel is a village in Surrey, situated on the banks of the River Mole at an elevation of around 88 metres. Capel is located near the villages of Clarks Green, Beare Green, and Newdigate, and is characterized by its semi-detached housing stock. Capel sits in a rural area, approximately 25.8 miles from London and 24.1 miles from Brighton and Hove. Capel has a population of around 887 residents.
Capel and Surrey: where our fuel drain cover runs
Capel rests in the RH postcode area, and the vans that answer petrol in diesel calls there work the spots near it as well — Clarks Green, Beare Green and Newdigate among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our engineers drain, and the vehicle does not need to come to us.
Still at the petrol pump in Capel?
The best place there is, then — that's where you are. Keep it off. Phone.