How Worried Should You Be? Petrol in a Diesel Car in The Bowl
Likely less than you are now — provided nobody has started it. Petrol resting in a diesel tank does nothing to your motor until something draws it through the system — your ignition priming your pump, the starter, or driving on its own. So the truthful answer to the first query everyone in The Bowl asks, "have I wrecked it?", is normally no. To keep the car like that, call Petrol in Diesel and leave your motor alone. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and the way to make sure you never repeat it.
Inside your engine: what petrol in a diesel does
On its way through a motor, diesel has two tasks. Before it burns, it lubricates — and then it combusts. Made to extremely fine tolerances, your injectors and your pump rely on the diesel moving through them to stop their surfaces wearing against one another.
Petrol handles the first job badly and the second not at all. The knocking comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication your system hinges on, and any pump running on that blend is wearing itself.
Put these together and the shape of the problem is clear. The damage is done by circulation, not by contact. Any tank with petrol in it is a fuel problem. Whatever a worn pump sheds goes on, carried by your fuel, into the injectors further along, which is why a pump that has worked on the petrol is where a mechanical problem begins.
The Bowl, petrol in a diesel: four cases, from mild to major
Filled up, and not started: no case is better. Just the tank has petrol in it, and so the job is clearing the tank and cleaning the fuel system where the vehicle sits. This situation can only really happen on a forecourt: anywhere else, the car got there by being driven.
Started for a moment, or just your ignition on. Petrol has come out of the tank and reached the filter and the lines, because the system has been bled. Usually nothing more than clearing, rinsing and sorting the fuel filter, so still easy.
Driven a few miles. Now the pump has spent these miles working on weakened fuel. Mileage is only half of that; how hard it was driven matters equally. Either way this work includes your tank, the fuel lines, the fuel filter and fresh fuel through the entire system. Short trips, like the school run to Cold Harbour Church of England School, are one matter. A run as far as Milton Keynes, under 3 miles away, is a very different task. So is any mileage on the M1, under 5 miles from The Bowl, where your engine has been running hard the whole time.
Knocking, an uneven idle, smoke, a throttle gone soft: driven till it complained. The motor is telling you the fuel is no longer acting like diesel. Stop where you are — on the verge on V4 Watling Street, at the kerb, down a side road — and don't move it. What goes first is still the fuel drain and flush, and that sorts it out, with lasting damage very unusual if a vehicle is pulled over early.
Stories The Bowl people hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Topping up removes nothing; it gives you a bigger tank of the same mix. The assumption behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Newer diesels can handle a little petrol" — a myth, and closer to the reverse. A newer diesel sends its fuel through more precise components at higher pressure, which makes the lubrication matter more, not less.
The myth that catches drivers off guard: if it starts and drives, it must be unharmed. Diesel in a petrol motor generally leaves a motor that will not run: the driver stops, and so does the damage. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile the pump grinds. Being able to run isn't proof of being fine.
An outdated workaround for a distinct issue is behind this one. Myth: "Add some two-stroke oil and drive the car home." None of what petrol diluted is put back by it — and later, your tank still contains the petrol.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol sits in the fuel filter and lines, ready to go right back through the pump at the next start. It's also really dangerous to drain petrol into a can by the kerbside.
Why petrol in a diesel takes place at all
Carelessness is rarely the cause, and no one means to do it. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol motor at all. The forecourt makes it easy, and the slip runs one way.
When routine and the vehicle stop matching, it happens. Hire cars, courtesy cars, and cars that are new to you. Households running one of each, petrol and diesel. Your ordinary forecourt, its pumps now in a different order. Filling up in a rush en route to Milton Keynes Central, with a train to catch. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. With rain, a call arriving, or a car full of children to deal with, your hand just does what it has always done.
How to prevent petrol in a diesel on your next fill-up in The Bowl
- Read the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what counts.
- Plenty of vehicles state the fuel inside the filler flap or on the cap, and so check there on the 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 your diesel's key when a home has one of each. So label it.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Daft, perhaps, but it works.
- While you're thinking about something else, this is an easy mistake to make — so put your phone away.
- Some diesels have a filler built 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 halfway? Stop there and then. A weaker mix results from less petrol inside your tank, but your next stage stays the same: don't crank it.
Already put petrol in a diesel around The Bowl?
The order of things is brief, then. Don't switch your ignition on, and don't crank it. If you are still on the forecourt — Shell or anywhere else — ask the staff to help you push the vehicle away from the pump. What was put in, roughly how much, and whether it's run: tell us that when you ring 0333 366 0103.
Say so if it was AdBlue instead of petrol: it's a separate fault, with its own page for The Bowl, since AdBlue brings corrosion and deposits rather than lost lubrication.
Why one petrol in a diesel task around The Bowl costs more than another
The four scenarios above are four different tasks, so no single price for this would be honest. Chiefly, the cost shifts with which one you're in. After that it is the ratio — how much petrol was put in against how much that tank holds — and after that where your car is and whether a van can reach it safely.
That's why we ask three questions before pricing rather than after: what got in, how much, and if it's run. Their replies are what turn a range into one firm number.
About The Bowl itself
The Bowl is a suburban area situated on the lakeside in Buckinghamshire, with a mix of terraced housing and local amenities. The Bowl sits at an elevation of 88 metres, close to the city of Milton Keynes and near other residential areas such as Elfield Park and Coffee Hall. The Bowl is located approximately 44 miles from London, making it a commuter-friendly location. The Bowl has a population of around 1866 residents, living in a predominantly terraced housing environment.
Fuel drain cover across Buckinghamshire, The Bowl included
The Bowl waits in the MK postcode area, and the vans that answer petrol in diesel jobs there work the spots around it as well — Elfield Park, Bleak Hall and Coffee Hall among them. You need not move your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
In The Bowl and still at the petrol pump?
Then, you could not be in a better place. Ring, and keep it turned off.