Petrol in a Diesel Car in Foster Street: How Worried Should You Be?
If it has not been started, you can worry far less than you likely are. Everyone around Foster Street starts with "have I wrecked it?", and the fair answer is usually no: petrol resting inside the tank of any diesel stays harmless until priming, cranking or driving pulls it into your fuel system. Leave the motor off then call Petrol in Diesel — that keeps it like that. The rest of this page sets out what petrol really does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you a second time.
Your engine and petrol in a diesel: what happens
Passing through a motor, diesel does two jobs at once. Before it ignites, it lubricates — and then it burns. Very fine tolerances are built into your injectors and your high-pressure pump, and only your diesel running through keeps their surfaces from grinding together.
Poorly at the first, not at all at the second: that is petrol. It's runnier than diesel and strips away the protection the system hinges on, and so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That's where the clattering comes from.
Combined, those leave the shape of the issue clear. It is movement that does the harm, not contact. All a tank with petrol in it amounts to is a fuel problem. Once your pump has been running on that petrol, a mechanical problem has started: anything shed by a pump that's grinding is carried downstream to your injectors with the fuel.
Petrol in a diesel in Foster Street: how serious is it? Four cases
Fuelled up, not once started. The best case there can be. At a forecourt, and really only there, that petrol is still confined to the tank — because anywhere else the vehicle was driven to get to it. The job is emptying and purging on the spot.
Ignition on, or started for a second. The system has been bled, and so petrol has left the tank and got to your filter and your lines. Still normally straightforward: drain, flush, and the fuel filter sorted.
A few miles driven, and your pump has spent every one of them running on thinned fuel. Tank, lines, filter, then clean fuel run through the entire system: that's this work, and the way your car was driven counts as much as the mileage. A school run to Henry Moore Primary School is one thing. A run as far as Chelmsford, under 15 miles away, is a very different job. So is any mileage on the M11, under a mile from Foster Street, where your engine has been working hard throughout.
It protested, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. That is your engine telling you its fuel has stopped behaving like diesel. Whether it's the verge on Hastingwood Park, a lay-by or a side street, stop where you are then leave it. What comes first is still the fuel drain and flush, and that takes care of it, with lasting damage very rare if a car is pulled over quickly.
Petrol in a diesel stories Foster Street drivers hear
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Topping up takes out nothing; it gives you a bigger tank of the same mix. A diesel fuel system does not tolerate petrol by percentage in the way that advice presumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. A newer diesel runs its fuel through smaller parts at higher pressure, which makes the lubrication matter more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools drivers. Feed diesel to a petrol engine and it generally will not run, so the motorist stops — and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile the pump grinds. Fine and running aren't the same thing.
Myth: a two-stroke additive lets you to drive home. It was an old fix, supposed for another issue. What petrol has thinned remains thinned, and that petrol remains inside the tank regardless.
The next start draws petrol back round your pump out of the lines and the filter, where some of it ends up after the motor has run. That is why a DIY tank drain does not sort it — a myth. Clearing petrol into a can by the kerbside is also genuinely hazardous.
How petrol ends up: petrol in a diesel
Nobody does it on purpose, and it is seldom carelessness. The forecourt makes it simple: the petrol nozzle is the smaller 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 motor at all. So the error runs one way.
When habit and the car stop matching, it happens. Courtesy car, hire car, or a motor that's brand new. Two vehicles on one driveway, one petrol, one diesel. Your normal forecourt, its pumps suddenly in a different order. A hurried fill en route to Harlow Mill with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a motorist accustomed to petrol: exactly when it happens. Throw in rain, a phone call or a back seat full of children, and your hand does what it has always done.
Avoiding petrol in a diesel next time you fill up in Foster Street
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most usually do. Read the petrol pump's label; the colour is just a hint.
- In a motor you don't know, look inside the flap over the filler or at the cap before your first fill: plenty of motors state the fuel there.
- Label your key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- Before the nozzle comes off the pump the first time you fill a hired or new motor, say "diesel" aloud. Daft, yes, but it works.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away then keep your mind on the pump.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to block a petrol nozzle, and aftermarket devices exist for the rest. Count it as a backstop, and keep reading the pump.
- Spotting it halfway? Stop there and then. A thinner blend follows from less petrol in that tank, but your next stage stays the same: do not fire it up.
Already put petrol in a diesel around Foster Street?
Then the order of things is brief. Do not turn your ignition on, and do not crank it. Ask the staff to help you roll it away from the petrol pump if you're still at the forecourt, whether that is BP or anywhere else. Then phone 0333 366 0103 and tell us what went in, roughly how much, and whether it has run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate fault — Foster Street has a page just for it.
One petrol in a diesel task in Foster Street costs more than another. Why?
An honest single price doesn't exist here: four scenarios, four separate jobs. What moves the cost is chiefly which of them you are in. Where the car is counts too, and whether a technician can safely get to it, after the share of petrol to what your tank holds.
Three questions come first, before any quote, rather than after — what got in, how much, has it run — and that is the reason. Given those answers, you get a straight figure rather than a range.
About Foster Street and its setting
Foster Street is a small village in Essex, situated inland at an elevation of around 100 metres, and is located approximately 21 miles from London. Foster Street has a mix of housing types, but semi-detached homes are predominant, and the village is near other communities such as Church Langley and Potter Street. Foster Street is close to the city of Chelmsford, which is about 14 miles away, and has a population of around 1206 residents.
Foster Street and Essex: where our fuel drain cover reaches
Foster Street waits in the CM postcode area, and the teams that answer petrol in diesel call-outs there work the spots around it as well — Church Langley, Potter Street and Hastingwood among them. No need to move your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
In Foster Street and still at the pump?
Nothing beats it: that's where you now are. Keep it off. Call.