Should You Worry? Petrol in a Diesel Car in Colebrook
Likely less than you are now — as long as nobody has started it. Petrol sitting in a diesel tank does nothing to your engine until something pulls it through the system — the ignition priming your pump, your starter, or the drive on its own. So the honest answer to the first question anyone around Colebrook asks, "have I ruined it?", is generally no. Keep it that way: leave the engine off and ring Petrol in Diesel. What petrol actually does to a diesel, how to gauge how far it has gone, and how to keep it from happening again: that's the remainder of this page.
Inside your engine: what petrol in a diesel really does
Passing through a motor, diesel is doing two things at once. Before it burns, it protects — then it combusts. The high-pressure pump and your injectors are built to very fine clearances, and your diesel passing through them is what keeps those surfaces from wearing against each other.
The second task petrol doesn't do at all, and the first it does poorly. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump on the blend wearing itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is why you get the clattering.
Put those together and the shape of the issue is plain. Not contact but movement is what does the harm. All a tank with petrol in it amounts to is a fuel problem. After the pump has been running on that petrol, a mechanical problem has started: anything shed by a pump that's grinding travels downstream to your injectors with the fuel.
How bad is petrol in a diesel? Four situations our technicians see around Colebrook
Fuelled but never started — the best it gets. Only your tank has petrol in it, and so the job is emptying the tank and flushing the system where your car stands. This situation can only really occur on a forecourt: anywhere else, the car got there by being driven.
A brief spell of running, or just your ignition on. Once primed, the system has drawn petrol out of your tank up to your filter and the fuel lines. Drain, flush, see to the fuel filter: still usually simple.
Those few miles on the road meant the pump working on fuel thinned by petrol the whole way. The work is that tank, your lines, the filter and fresh fuel through the whole system, and how hard the car was driven counts as much as how far. The school run to Willowbank Primary School is one matter. A run as far as Exeter, under 15 miles away, is a very different job. So is any mileage on the M5, under a mile from Colebrook, where the motor has been working hard the whole time.
Driven on until it complained — rattling, smoke, a ragged idle, a dead throttle. The engine is telling you the fuel is no longer acting like diesel. Whether it's the verge on Colebrook Lane, a lay-by or a side street, stop there and leave it. What comes first is still the drain and flush, and that takes care of it, with permanent damage very unusual when a car is stopped soon.
Colebrook drivers and the petrol in a diesel stories they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." A bigger tank of the same mixture is all you get, because topping up removes nothing. That advice assumes a diesel fuel system handles petrol by percentage. It does not.
If anything, the reverse holds. Myth: "A newer diesel can cope with a bit of petrol." Smaller components and higher pressure are the way a newer diesel runs its fuel, and that makes the lubrication matter more, not less.
"It starts, it drives, so no harm done" — the myth that catches most drivers than any other. The motorist of a petrol motor fed diesel usually stops, because it will not run, and the harm stops with them. Whilst your pump wears, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. Fine and running aren't the same thing.
An old workaround for a distinct issue lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." The petrol is still in the tank after that, and what it has weakened is not put back.
Myth: "Drain that tank yourself and you are sorted." After the engine has been run, some of that petrol is no longer inside your tank: it is in the filter and the lines, and it goes right back through the pump on the next start. On top of that, petrol drained into a can by the road is truly risky.
How does petrol in a diesel happen?
No one does it on purpose, and it's seldom carelessness. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle mostly won't go into a petrol motor at all. So the slip runs one way.
Routine and the car falling out of step is how it takes place. Hire cars, courtesy cars, and cars that are new to you. A household with one petrol and one diesel on the drive. Your ordinary forecourt, its pumps suddenly in a different order. Rushing for a train at Tiverton Parkway and fuelling up en route. A new-to-you diesel Renault Megane, its first fuelling, and a motorist used to petrol: precisely when it occurs. The hand does what it has always done when you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel at your next fill-up in Colebrook
- The label is what matters, and so read the petrol pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- In a car you don't know, look inside the flap over your filler or at the cap before your first fill: many motors print the fuel there.
- A coloured fob or a sticker on your diesel's key does more than any amount of intending to remember, in a house with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It sounds daft and it works.
- Put the phone away. This is an easy mistake to make while you are thinking about something else.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Stop the moment you notice. Less petrol in the tank makes a weaker blend. It does not change what to do next, which is still not to fire it up.
Put petrol in a diesel in Colebrook already?
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 pump if you're still at the forecourt, whether that is Gulf or anywhere else. Next, 0333 366 0103. We'll ask what went in, about how much, and if it's been run.
If it was AdBlue and not petrol, say so. That is a separate issue — corrosion and deposits instead of lost lubrication — and it has its own page for Colebrook.
Colebrook petrol in a diesel tasks: why one costs more than another
There is no fair single quote for this, since the four situations above are four separate jobs. Mostly, your cost moves with which situation you are in. Where the vehicle is matters too, and whether a technician can safely get to it, after the ratio of petrol to what the tank holds.
Three questions come first, before any quote, rather than after — what went in, how much, has it run — and that is the reason. The replies turn a range into a straight figure.
About Colebrook
Colebrook is a small hamlet situated on the riverside in Devon, with a relatively low elevation of 91 metres. Colebrook lies close to the city of Exeter, approximately 10 miles away, and is near other local places such as Knowle and Ponsford. Colebrook has a population of around 538 people, predominantly living in semi-detached housing. Colebrook is located in the South West region of England, about 149 miles from London.
Fuel drain cover across Devon, Colebrook included
Knowle, Ponsford and Cullompton are among the locations around Colebrook that the same teams work, answering petrol in diesel jobs across Colebrook's EX postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots our technicians drain, and your vehicle doesn't need to move to us.
At the pump in Colebrook, still?
Nothing beats it: that's where you now are. Phone, and keep it switched off.