Should You Worry? Petrol in a Diesel Car in The Heugh
Probably less than you are now — provided nobody has started the vehicle. Until your ignition primes the pump, your starter cranks, or the vehicle is driven, petrol in a diesel tank just sits there and does no harm. Which makes the truthful reply to the first The Heugh question — "have I wrecked it?" — normally no. Keep it that way: leave your motor off then ring Petrol in Diesel. 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 goes on
Passing through an engine, diesel does two things at once. It lubricates to begin with, and only then does it burn. What stops the surfaces inside the high-pressure fuel pump and the fuel injectors from grinding against one another is the diesel passing through them — they are made to extremely fine clearances.
Petrol handles the first task poorly and the second not at all. The clattering comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection the fuel system rests on, and any pump working on such a mix is wearing itself.
Seen together, they show the shape the issue has. It is movement that does the damage, not contact. Where the petrol is only inside the tank, it's an issue of fuel, nothing more. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the fuel injectors further on.
The Heugh, petrol in a diesel: four situations, from mild to serious
Filled up, not once started. The best case there can be. Only your tank has petrol in it, and so the task is emptying your tank and rinsing the system where your car stands. This situation can only really take place on a forecourt: anywhere else, the car got there by being driven.
A brief spell of running, or just the ignition on. With the fuel system primed, the fuel lines and filter already contain petrol that has come from that tank. Still normally straightforward: drain, flush, and the fuel filter sorted.
Those few miles on the road meant the pump labouring on fuel weakened by petrol the whole way. Mileage is only half of it; how hard it was driven matters just as much. Either way the work includes your tank, your lines, your filter and clean fuel through the whole circuit. A school run to the local primary school is one thing. Getting as far as Edinburgh, under 10 miles away, makes a very different task — as does any distance on the M8, under 15 miles from The Heugh, with the engine working hard the whole time.
Clattering, an uneven idle, smoke, a throttle gone soft: driven until it complained. The fuel is not behaving like diesel any more, and your engine is saying so. Leave it where it stops: a lay-by, a side street, the verge on Market Way. A car stopped soon very rarely has lasting damage, as the drain and the flush-through, which still come first, take care of it.
The Heugh people and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing comes out when you top up — that tank just holds more of the same mixture. The assumption behind the guidance — that diesel fuel systems accept petrol by percentage — is wrong.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. At higher pressure, through smaller components: that is how a newer diesel handles its fuel, and so the lubrication counts for more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no harm done." Feed diesel to a petrol engine and it usually won't run, so the driver stops — and the harm stops with them. A diesel fed petrol usually starts, ticks over and drives away as if nothing has happened, while the pump wears. A running engine does not mean fine.
An outdated workaround for a different fault lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has diluted remains weakened, and that petrol remains inside that tank anyway.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol lies in the filter and lines, waiting to go right back through the pump on your next start. Draining petrol into a can at the kerbside is also really risky.
Why petrol in a diesel occurs so easily
Carelessness is seldom the cause, and nobody means to do it. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol car at all. The forecourt makes it easy, and the error runs one way.
When habit and the car stop matching, it occurs. Any motor that's new to you — a hire car, on loan as a courtesy car, or just bought. Two vehicles on one driveway, one petrol, one diesel. A familiar forecourt with the pumps in a different order. Filling up in a hurry on the way to Prestonpans, with a train to catch. Years of petrol cars behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that's when. With rain, a call arriving, or children to deal with, the hand simply does what it has always done.
How to avoid petrol in a diesel on your next fill-up around The Heugh
- The label is what matters, and so check the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- Inspect your filler flap. Plenty of vehicles state the fuel inside the flap or on the cap. Look at it on your first fill in any motor you don't know.
- Mark 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 meaning to remember.
- Before the nozzle comes off the pump the first time you fill a hired or new motor, say "diesel" out loud. Daft, perhaps, yet it works.
- While you're thinking about something else, this is an easy mistake to make — so put the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to reject a petrol nozzle, and add-on devices are available for vehicles without one. They are a safety net, not a reason to stop checking the petrol pump.
- The moment you notice, stop: less petrol inside your tank means a weaker blend. What to do next does not change, though — still do not start the vehicle.
The Heugh: already put petrol in a diesel?
The order of things is short, then. Do not turn the ignition on, and do not start it. The attendants at the forecourt — whether at JET itself or wherever you filled up — will usually help roll 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.
Corrosion and deposits are the trouble with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and read its own The Heugh page.
The Heugh petrol in a diesel jobs: why one costs more than another
A fair single quote does not exist here: four scenarios, four separate tasks. What shifts your cost is chiefly which of them you are in. Next it's the proportion — how much petrol went in against how much that tank takes — and after that where your car is and whether a technician can reach it safely.
Before any quote, not after, we ask three questions: the fuel that went in, the volume, and whether it has run. That is why. Those replies are what change a range into one firm number.
About The Heugh, briefly
The Heugh is a coastal suburban area in East Lothian, situated near the city of Edinburgh and overlooking the Firth of Forth. The Heugh sits at an elevation of 78 metres, with detached housing being the predominant type of accommodation in the area. The Heugh is located close to nearby places such as Tranent and Meadowmill, and is approximately 8.8 miles from Edinburgh. The Heugh has a population of around 3312 residents.
Fuel drain cover around The Heugh and across East Lothian
Tranent, Meadowmill and Meadowmill Cottages are among the spots near The Heugh that the same teams work, answering petrol in diesel call-outs across The Heugh's EH postcode area. Our engineers drain where the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
The Heugh: still at the petrol pump?
Then you're in the best spot there is. Ring, and leave it turned off.