Should You Worry? Petrol in a Diesel Car in Drumlough
Unstarted? Then less anxious than you probably feel. Everyone in Drumlough begins with "have I ruined it?", and the fair answer is generally no: petrol resting inside your tank of any diesel stays harmless until priming, cranking or driving draws it into your fuel system. To leave the vehicle that way, phone Petrol in Diesel then leave the engine switched off. The remainder of this page explains what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
The motor and petrol in a diesel: what happens
On its way through a motor, diesel does two jobs. It combusts, and before it burns it protects. Very fine gaps are built into the fuel injectors and your high-pressure pump, and only your diesel flowing through keeps those surfaces from grinding together.
The second task petrol doesn't do at all, and the first it does poorly. It is thinner than diesel and takes away the protection your fuel system depends on, so a pump running on a petrol blend 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 is where the rattling comes from.
Together, those make the shape of the issue plain. The damage is done by movement, not by contact. Where that petrol is only in that tank, it's an issue of fuel, nothing more. The start 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 your injectors beyond it.
Four situations our technicians see around Drumlough: how bad is petrol in a diesel?
Fuelled up, not once started. The best case there can be. At a forecourt, and genuinely only there, the petrol is still limited to your tank — because everywhere else your car was driven to get to it. The task is draining and cleaning on the spot.
A moment's running, or merely your ignition on. Petrol has left that tank and got to the fuel filter and your lines, since the system has been bled. Still generally easy: drain, flush, and the fuel filter seen to.
Your pump has spent a couple of miles on thinned fuel — that's what driving it does. Distance is only half of that; how hard it was driven counts just as much. Either way the work runs to the tank, your lines, your filter and fresh fuel through the entire system. Driving the kids to the local primary school is one sort of trip. Very different again: a trip to Lisburn, under 10 miles away, or any mileage on the M77, over 50 miles from Drumlough, where the motor never stopped working hard.
Knocking, a lumpy idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you the fuel is no longer acting like diesel. Whether it's the verge on South Crescent, a lay-by or a side street, stop where you are and leave it. What comes first is still the drain and flush-through, and that sorts it out, with permanent damage very unusual if a vehicle is stopped early.
What Drumlough motorists get told about petrol in a diesel — and the stories in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." A bigger tank of the same mix is all it gives, since topping up removes nothing. A diesel fuel system does not tolerate petrol by percentage in the way that guidance assumes.
Not so: a current diesel copes with a bit of petrol. Rather, the opposite. A modern diesel runs its fuel through finer parts at higher pressure, which makes the lubrication matter more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that fools drivers. Any petrol motor fed diesel generally won't run, and so the driver stops and the damage 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 different problem. The petrol is still inside your tank afterwards, and whatever it has diluted is not put back.
Myth: "Drain your tank yourself and you are sorted." After the engine has been run, some of the petrol is no longer inside that tank: it is in your filter and your lines, and it goes right back through your pump at the next start. And, a can of petrol drained at the roadside is truly hazardous.
How does petrol in a diesel take place?
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the smaller of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol car at all. The forecourt makes it easy, and the mistake runs one way.
It takes place when habit and the vehicle stop matching. Courtesy car, hire car, or a vehicle that is new. Two cars on one drive, one petrol, one diesel. Your ordinary forecourt, its pumps suddenly in a different order. Rushing for a train at the nearest station and filling up en route. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it occurs. Your hand does what it has always done when you add rain, a phone call or a back seat full of kids.
Next time you fill up around Drumlough: preventing petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Check the pump's label; the colour is just a clue.
- The first fill in a new car is the time to check your filler flap — inside it, or on the cap, many vehicles state which fuel to use.
- Good intentions count for less than a sticker or a fob in a bright colour on your diesel's key when a house has one of each. So label it.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car needs its first tank. It sounds daft. It does the trick.
- Whilst you are thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Add-on devices exist for motors without one, and some diesels are built with a filler that will not take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Less petrol makes a weaker blend, and so stop the moment you notice — while remembering that the next stage is unchanged. It is still not to start it.
Petrol already in a diesel around Drumlough? Start here
Short and simple, then, is the order of things. Starting it is out, and so is turning on the ignition. Ask the attendants to help you push it clear of the pump if you are still at the forecourt, whether that's the nearest petrol station or anywhere else. Ring 0333 366 0103 next, with three facts — the fuel, the rough volume, and if it's run.
Corrosion and deposits are the problem with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and read its own Drumlough page.
Drumlough petrol in a diesel tasks: why one costs more than another
There is no honest single price for this, since the four scenarios above are four separate jobs. Which of them you are in is chiefly what moves the cost. Beyond that it is the ratio — how much petrol got in against how much the tank takes — and after that where your car is and whether a van can get to it safely.
Before any quote, not after, come three questions: your fuel that went in, the volume, and whether it has run. That's why. The answers change a range into a straight figure.
About Drumlough and where it is
Drumlough is a small locality in County Down, situated inland at an elevation of 148 metres, approximately 5.7 miles from Lisburn. Drumlough is characterized by its predominantly detached housing stock, reflecting its rural setting. Drumlough sits near other localities such as Magheraconluce, Annahilt, and Ravernet, in the rolling countryside of Northern Ireland.
Drumlough and County Down: where our fuel drain cover reaches
Petrol in diesel jobs around Drumlough — part of the BT postcode area — go to vans that likewise cover the spots about it, Magheraconluce, Annahilt and Ravernet among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations our technicians drain, and your vehicle doesn't need to come to us.
In Drumlough and still at the petrol pump?
Then, you could not be in a better place. Keep it off. Call.