Great Horkesley: Petrol in a Diesel Car? How Worried to Be
Far less than you probably are, provided it hasn't been started. Until the ignition primes your pump, your starter cranks, or your vehicle is driven, petrol in a diesel tank simply waits there and does nothing. Which means the honest reply to that first Great Horkesley question — "have I ruined it?" — normally no. Petrol in Diesel is who to phone, with the engine left off, so it stays that way. Keep reading for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and ways to make sure you never repeat it.
Inside the motor: what petrol in a diesel does
Diesel does two tasks on its way through a motor. It burns, and before it ignites it protects. What keeps the surfaces inside your high-pressure pump and the fuel injectors from wearing down against one another is your diesel passing through them — they're built to extremely fine tolerances.
Of these two jobs, petrol handles the first badly and the second not at all. A pump running on a petrol mixture is wearing itself out, because petrol is thinner than diesel and takes away the lubrication 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 is where any clattering comes.
The shape of the issue is clear once you put those together. The harm is done by circulation, not by contact. Petrol in a tank is a fuel problem. Whatever a worn pump sheds goes on, carried by your fuel, into your injectors downstream, which is why a pump that has been working on the petrol is where a mechanical fault begins.
Great Horkesley, petrol in a diesel: four cases, from mild to significant
Fuelled, and not started: no case is better. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol kept in the tank alone, it's cleared and flushed on the spot, and nothing more is needed.
Ignition on, or started for a second. Once primed, the system has drawn petrol from the tank up to the filter and the fuel lines. Still generally simple: drain, flush, and the filter seen to.
The pump has worked a couple of miles on weakened fuel — that's what driving the vehicle does. Mileage is only half of that; how hard it was driven counts just as much. Either way this work runs to that tank, the fuel lines, your filter and fresh fuel through the entire circuit. A school run to The Bishop William Ward Church of England Primary School is one thing. Very different again: a run to Colchester, under 3 miles away, or some distance on the M11, under 50 miles from Great Horkesley, where the engine kept labouring hard.
Clattering, an uneven idle, smoke, a throttle gone soft: driven until it complained. The motor is telling you the fuel is no longer acting like diesel. Whether it is the verge on The Causeway, a lay-by or a side road, stop where you are then leave it. A vehicle stopped quickly very rarely has permanent damage, as the fuel drain and the flush, which still go first, take care of it.
Stories Great Horkesley motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It does not. Nothing comes out when you top up — the tank just carries more of the same mixture. Percentage is not how a diesel fuel system tolerates petrol, however much that guidance assumes.
Not so: a newer diesel copes with a bit of petrol. If anything, the reverse. A current diesel sends its fuel through smaller components at higher pressure, which makes the protection count more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there's no damage done." The motorist of a petrol motor fed diesel normally stops, since it will not run, and the harm stops with them. Feed petrol to a diesel and it generally starts, idles and pulls away like nothing has happened — all the while its pump is wearing. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct fault. None of what petrol weakened is put back by it — and later, your tank still contains that petrol.
The next start draws petrol back round your pump from your lines and the filter, where some of that sits once your engine has been run. That is why draining the tank yourself doesn't leave you sorted — a myth. It's also genuinely dangerous to drain petrol into a can by the roadside.
Why petrol in a diesel happens at all
It's seldom carelessness, and nobody does it on purpose. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol motor at all. The forecourt makes it simple, and the slip runs one way.
It occurs when routine and the car stop matching. A new car, a hire car or a courtesy car. Households running one of each, petrol and diesel. The pumps in a different order on a familiar forecourt. A rushed fill on the way to Colchester with a train to catch. A new-to-you diesel Nissan Qashqai, its first fuelling, and a motorist accustomed to petrol: precisely when it occurs. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel at your next fill-up in Great Horkesley
- Check the pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what counts.
- Check your filler flap. Plenty of cars state the fuel inside the flap or on the cap. Look at it on your first fill in a motor you do not know.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key when a home has one of each. So label it.
- Before the nozzle comes off the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Silly, perhaps, yet it works.
- Put your phone away. This is an easy mistake to make whilst you are thinking about something else.
- Some diesels come with a filler designed to refuse a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- Spotting it mid-fill? Stop at once. A thinner mix results from less petrol in the tank, but the next step stays the same: do not crank it.
Great Horkesley: already put petrol in a diesel?
Then the order of things is short. Starting it is out, and so is switching on the ignition. Ask the staff to help you roll it clear of the petrol pump if you're still at the forecourt, whether that is Gulf or anywhere else. Then call 0333 366 0103 and tell us what went in, roughly how much, and if it has run.
Corrosion and deposits form the issue with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and read its own Great Horkesley page.
Great Horkesley petrol in a diesel jobs: why one costs more than another
There is no fair single price for this, because the four scenarios above are four different jobs. The situation itself does most of the work of moving the cost. Beyond that it's the ratio — how much petrol got in against how much the tank holds — and then where the vehicle is and whether a van can get to it safely.
That's why our technicians ask three questions before quoting instead of after: what got in, how much, and whether it's run. Their answers are what turn a range into one firm number.
About Great Horkesley and its setting
Great Horkesley is a village in Essex, situated on the banks of the River Colne, with Horkesley Heath and Tye Green nearby. Great Horkesley has a population of around 1054 people, living in predominantly detached houses, and is located close to the city of Colchester. Great Horkesley sits at an elevation of 49 metres, in a riverside setting that offers scenic views of the surrounding countryside. Great Horkesley is also near to Mile End, and is around 52 miles from London.
Across Essex and around Great Horkesley: fuel drain cover
Great Horkesley rests in the CO postcode area, and the teams that answer petrol in diesel call-outs there work the spots around it as well — Horkesley Heath, Tye Green and Mile End among them. We drain wherever your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Still at the petrol pump around Great Horkesley?
Then you're in the best spot there can be. Keep the car turned off, and ring.