Petrol in a Diesel Car in Hemyock: How Worried Should You Be?
Likely less than you already are — provided nobody has started the vehicle. Everyone around Hemyock starts with "have I wrecked it?", and the honest answer is generally no: petrol resting in the tank of any diesel remains harmless until priming, cranking or driving pulls it into the fuel system. To keep the car that way, ring Petrol in Diesel and leave the engine alone. What petrol really does to a diesel, how to gauge how far it's gone, and how to keep it from happening a second time: that is the rest of this page.
What petrol in a diesel does to your engine
Diesel has two jobs on its way through an engine. Before it burns, it protects — then it combusts. What keeps the surfaces inside the high-pressure fuel pump and the injectors from wearing against each other is your diesel passing through them — they are designed to extremely fine clearances.
The second job petrol does not do at all, and the first it does badly. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump on that mixture to wear itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the knocking.
Combined, those leave the shape of the problem plain. Contact doesn't do the damage — movement does. Petrol in the tank is a fuel fault. The beginning of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds moves on with your fuel to the injectors downstream.
How serious is petrol in a diesel? Four scenarios our engineers see around Hemyock
Filled up, never started. The best case there can be. On a forecourt, and genuinely only there, that petrol is still confined to the tank — because everywhere else the car was driven to get to it. The job is draining and purging on the spot.
Started for a moment, or only the ignition on. Petrol has come out of that tank and got to your filter and your lines, since the system has been bled. Still generally simple: drain, flush, and the filter dealt with.
Those few miles driven meant the pump labouring on fuel thinned by petrol throughout. The work is that tank, the lines, the fuel filter and fresh fuel through the entire system, and how hard your car was driven counts as much as how far. On the school run to Hemyock Primary School, the mileage is short. Very different once more: a run to Exeter, under 25 miles away, or some mileage on the M5, under 5 miles from Hemyock, where the engine kept working hard.
Driven on till it complained — clattering, smoke, a lumpy idle, a soft throttle. The motor is telling you the fuel is no longer acting like diesel. Pull up on the spot — on the verge on Fore Street, at the kerb, down a side road — and do not move it again. The fuel drain and flush still come first, and they deal with it: if a car is pulled over soon, long-term damage is very rare.
Hemyock motorists and the petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. That advice presumes a diesel fuel system handles petrol by percentage. It doesn't.
"Newer diesels can handle a little petrol" — a myth, and closer to the reverse. A current diesel runs its fuel through more precise parts at higher pressure, which makes the protection matter more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools drivers. The motorist of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the damage stops there. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, while your pump grinds. Being able to run is not the same as being fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an old fix for a different problem. None of what petrol thinned is put back by it — and later, the tank still holds that petrol.
Myth: "Drain your tank yourself and you are sorted." Once the motor has been run, some of the petrol is no longer inside the tank: it is in the fuel filter and the lines, and it goes right back through the pump at the next start. Clearing petrol into a can at the roadside is also really dangerous.
Why petrol in a diesel takes place at all
On purpose? Never. Through carelessness? Seldom, if ever. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol car at all. The forecourt makes it easy, and the error runs one way.
Habit and the car getting out of step is how it occurs. Courtesy car, hire car, or a motor that's new. Two motors on one drive, one petrol, one diesel. The pumps in a different order on a familiar forecourt. Fuelling up in a hurry on the way to Tiverton Parkway, with a train to catch. Precisely the moment it happens: after years of driving petrol, someone fills a diesel Renault Megane for the first time. Throw in a back seat full of children, a phone call or rain, and the hand takes over.
Hemyock drivers: how to prevent petrol in a diesel next time
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Check the petrol pump's label; the colour is just a clue.
- In a vehicle you do not know, look inside the flap over the filler or at the cap before the first fill: plenty of motors print the fuel type there.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, in a home with one of each.
- Before the nozzle leaves the pump the first time you fill a hired or new car, say "diesel" aloud. Silly, perhaps, yet it works.
- Mistakes like this are simple to make whilst your mind is on something else, and so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to block a petrol nozzle, and add-on devices exist for motors without one. They are a safety net, not a reason to stop reading the pump.
- The moment you realise, stop: less petrol in the tank makes a weaker mixture. What to do next doesn't change, though — still don't crank it.
Hemyock: already put petrol in a diesel?
Then the order of things is brief. Leave it unstarted, with your ignition switched off too. The staff on the forecourt — whether at Regent itself or wherever you filled up — will usually help roll it away from the petrol pump if you ask. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it has been run.
Corrosion and deposits are the problem with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and see its own Hemyock page.
Hemyock petrol in a diesel jobs: why one costs more than another
There's no honest single price for this, because the four scenarios above are four different jobs. What shifts the cost is mostly which of them you are in. Two things follow that: the petrol that was put in as a proportion of what that tank takes, then the place the car is in and whether a technician can reach it safely.
Three questions come first, before quoting, instead of after — what got in, how much, has it run — and that is the reason. A range becomes a straight figure when those answers are in.
About Hemyock, for a moment
Hemyock is a village in Devon, situated on the River Culm and surrounded by rolling hills. Hemyock sits at an elevation of around 140 metres, with the village centre close to the river and the nearby settlements of Millhayes and Ashculme. Hemyock has a mix of old and new housing, with detached homes being the predominant type, and is located approximately 18.7 miles from Exeter. Hemyock is also within commuting distance of larger cities, with London being around 140.4 miles away.
Fuel drain cover around Hemyock and across Devon
Petrol in diesel calls around Hemyock — part of the EX postcode area — go to teams that also cover the spots round it, Millhayes, Ashculme and Culm Davy among them. You need not move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
In Hemyock and still at the petrol pump?
Then, you could not be in a better spot. Call, and keep it switched off.