Green End: Petrol in a Diesel Car? How Worried to Be
If it hasn't been started, worry less than you probably are. Everyone around Green End starts with "have I wrecked it?", and the fair answer is generally no: petrol resting inside the tank of any diesel stays harmless until priming, cranking or driving draws it into the fuel system. To leave the car like that, phone Petrol in Diesel then leave your motor alone. What petrol actually does to a diesel, how to gauge how far it has gone, and how to keep it from happening again: that is the rest of this page.
What petrol in a diesel does to the engine
On its way through a motor, diesel does two tasks. Before it ignites, it protects — then it ignites. Extremely fine tolerances are built into the fuel injectors and the high-pressure pump, and just your diesel flowing through keeps their surfaces from grinding together.
The second job petrol doesn't do at all, and the first it does badly. It is thinner than diesel and removes the lubrication your fuel system hinges on, so a pump running on a petrol mixture is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the clattering comes from.
Combined, those make the shape of the problem clear. The harm is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel issue. After the pump has been working on that petrol, a mechanical fault has started: whatever is shed by a pump that is grinding travels downstream to your injectors with your fuel.
Green End, petrol in a diesel: four cases, from mild to major
Filled but not once started — the best it gets. At a forecourt, and really only there, the petrol is still confined to your tank — since everywhere else your car was driven to get to it. The job is emptying and cleaning on the spot.
A brief spell of running, or merely the ignition on. Petrol has left that tank and got to your filter and the lines, since the fuel system has been bled. Drain, flush, deal with your filter: still usually simple.
Those few miles on the road meant the pump running on fuel diluted by petrol the whole way. Mileage is only half of it; how hard it was driven counts equally. Either way this work runs to that tank, the fuel lines, the filter and clean fuel through the whole system. On the school run to Gamlingay Village Primary, the distance is short. A run as far as Cambridge, under 15 miles away, is a very different job. So is any miles on the A1(M), under 10 miles from Green End, where the engine has been working hard throughout.
Driven on till it protested — rattling, smoke, an uneven idle, a soft throttle. The fuel is not acting like diesel any more, and the engine is saying so. Stop wherever you are — the verge on St Edes Way, a lay-by, a side street — then leave it there. A car pulled over soon very seldom has lasting damage, as the drain and the flush, which still come first, deal with it.
Green End drivers and the petrol in a diesel myths they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." A fuller tank of the same mix is all it gives, because topping up takes out nothing. Percentage isn't how a diesel fuel system tolerates petrol, whatever that advice presumes.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." Smaller parts and higher pressure are how a modern diesel runs its fuel, and that makes the protection matter more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there is no damage done." The driver of a petrol engine fed diesel usually has no choice but to stop, because it will not run, and the harm stops there. Feed petrol to a diesel and it normally starts, idles and pulls away like nothing has happened — all the while its pump is wearing. Being able to run isn't the same as being fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old fix, supposed for another issue. It doesn't put back what petrol has thinned, and that petrol is still in the tank after that.
Myth: "Drain the tank yourself and you're sorted." Once the engine has run, some of that petrol is no longer in the tank: it is in the fuel filter and the lines, and it goes right back through your pump on the next start. Draining petrol into a can by the roadside is also really dangerous.
How it happens: petrol in a diesel
No one does it on purpose, and it's rarely carelessness. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol car at all. The forecourt makes it simple, and the mistake runs one way.
Routine and your car getting out of step is when it happens. Any vehicle that is new to you — hired, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. A hurried fill on the way to Sandy with a train to catch. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that is when. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
Green End motorists: how to avoid petrol in a diesel next time
- Green for unleaded and black for diesel is usual in the UK — but not on every forecourt. Trust the label on the pump, not the colour.
- Check your filler flap. Many motors state the fuel inside the flap or on the cap. Look at it on your first fill in any motor you don't know.
- Good intentions count for less than a sticker or a fob in a bright colour on the diesel's key when a household has one of each. So mark it.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car needs its first tank. It seems daft. It works.
- Put the phone away. This is an easy mistake to make while you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to block a petrol nozzle, and aftermarket devices exist for the rest. Treat it as a backstop, then keep reading the petrol pump.
- Spotting it halfway? Stop at once. A thinner mixture results from less petrol in your tank, yet the next stage stays the same: do not crank it.
Petrol already in a diesel around Green End? Start here
The order of things is brief, then. Starting it is out, and so is switching on the ignition. Still at the forecourt, at Gulf or anywhere else? Ask the attendants to help you push the vehicle away from the petrol pump. Ring 0333 366 0103 next, with three facts — the fuel, the approximate quantity, and whether it's run.
Corrosion and deposits are the problem with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and read its own Green End page.
What makes one Green End petrol in a diesel job cost more than the next
A fair single price does not exist here: four situations, four separate jobs. What moves the cost is chiefly which of them you're in. The share matters next, meaning how much of the tank is petrol, and then the position of your car and whether reaching it is safe for a technician.
Three queries come first, before quoting, instead of after — what went in, how much, has it run — and that is the reason. Given those answers, there is a straight figure rather than a range.
About Green End and its setting
Green End is a suburban area in Cambridgeshire, situated inland at an elevation of 57 metres, and located approximately 13.8 miles from Cambridge. Green End has a mix of housing types, but is predominantly characterised by terraced homes. Green End is part of the wider commuter belt, with London being around 45 miles to the south. Green End is close to nearby places such as Gamlingay and Little Heath.
Across Cambridgeshire and in Green End: fuel drain cover
Petrol in diesel calls around Green End — part of the SG postcode area — go to vans that also cover the locations round it, Gamlingay, Dennis Green and Little Heath included. No need to bring the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
At the pump around Green End, right now?
In that case, you could not be in a better place. Turned off it stays; then call.