Weston Turville: Petrol in a Diesel Car? How Worried to Be
Likely less than you already are — as long as nobody has started the vehicle. Until your ignition primes the pump, the starter cranks, or your vehicle is driven, petrol in a diesel tank just sits there and does no harm. Which makes the truthful reply to the first Weston Turville question — "have I ruined it?" — normally no. To leave the car like that, ring Petrol in Diesel and leave your motor alone. What petrol really does to a diesel, how to gauge how far it has travelled, and how to stop it from happening again: that is the remainder of this page.
Petrol in a diesel: what does it do to the engine?
On its way through an engine, diesel has two tasks. Oiling comes before burning; it does both. Very fine clearances are built into the injectors and the high-pressure pump, and just your diesel running through keeps those surfaces from grinding together.
Poorly at the first, not at all at the second: that is petrol. A pump running on a petrol mix is wearing itself out, because petrol is thinner than diesel and strips out the protection the fuel system relies on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that's where any knocking starts.
The shape of the issue is clear when you put those together. It is circulation that does the harm, not contact. All a tank with petrol in it amounts to is a fuel issue. After your pump has been working on that petrol, a mechanical fault has started: anything shed by a pump that's wearing down is carried onward to the injectors with the fuel.
Weston Turville, petrol in a diesel: four cases, from mild to serious
The best case there can be: filled up, never started. Only the tank has petrol in it, so the job is clearing the tank and flushing the system where the car stands. This scenario can only truly happen on a forecourt: anywhere else, the vehicle got there by being driven.
A moment's running, or merely your ignition on. Once primed, your system has pulled petrol from the tank up to the filter and the lines. Drain, flush, see to your filter: still normally simple.
Some miles driven, and your pump has spent every one of them labouring on thinned fuel. How hard the vehicle was driven counts as much as how far, and the work takes in your tank, your lines, the fuel filter and clean fuel through the whole circuit. The school run to Weston Turville Church of England School is one matter. Getting as far as Milton Keynes, under 25 miles away, makes a very different task — as does any miles on the M40, under 15 miles from Weston Turville, with the engine running hard all the way.
Driven on till it complained — rattling, smoke, a ragged idle, a soft throttle. That is your motor telling you its fuel has stopped acting like diesel. Pull up where you are — on the verge on The Hyde, at the kerb, down a side road — and don't move it again. Long-term damage is very uncommon if a vehicle is stopped quickly, and the fuel drain and flush-through that still go first deal with it.
What Weston Turville drivers get told about petrol in a diesel — and the myths 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 you get, because topping up takes out nothing. A diesel fuel system doesn't tolerate petrol by percentage in the way that advice supposes.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. A current diesel sends its fuel through smaller components at higher pressure, which makes the lubrication count more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that fools drivers. A petrol motor fed diesel normally won't run, so the driver stops and the damage stops with them. Whilst your pump wears, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Being able to run isn't the same as being fine.
Myth: a two-stroke additive lets you to drive home. It is an old fix, meant for another fault. It does not put back what petrol has diluted, and the petrol is still in that tank later on.
The next start draws petrol back round your pump from your lines and your filter, where some of it ends up once the engine has run. That's why a DIY tank drain does not sort it — a myth. Also, a can of petrol drained at the roadside is truly dangerous.
Petrol in a diesel: how does it happen?
On purpose? Never. Through carelessness? Seldom, if ever. 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 error runs one way.
It happens when habit and the car stop matching. Any car that's new to you — a hire car, on loan as a courtesy car, or just bought. One petrol and one diesel on the driveway of the same household. The pumps in a different order on a familiar forecourt. A hurried fill on the way to Stoke Mandeville with a train to catch. Years of petrol vehicles behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that's when. The hand does what it has always done once you add rain, a phone call or a back seat full of children.
How to avoid petrol in a diesel on your next fill-up in Weston Turville
- The label is what matters, and so read the pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- In a car 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.
- One of each in the home? Label your key to your diesel — a bright fob, a sticker — since intending to remember isn't enough.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Silly, perhaps, yet it works.
- Mistakes like this are straightforward to make whilst your mind is on something else, so your 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 are available for cars without one. They are a safety net, not a reason to stop reading the petrol pump.
- Spotting it mid-fill? Stop at once. A thinner mixture follows from less petrol inside that tank, but your next step remains the same: do not start the vehicle.
Weston Turville: already put petrol in a diesel?
Then the order of things is short. Do not switch the ignition on, and don't fire it up. If you are still at the forecourt — the nearest petrol station or anywhere else — ask the staff to help you roll the vehicle away from the pump. Then phone 0333 366 0103 and tell us what got in, roughly how much, and if it has run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a different issue — Weston Turville has a page just for it.
One petrol in a diesel job in Weston Turville costs more than another. Why?
Four separate jobs lie behind the four situations above — which is why there's no fair single price. Which of them you're in is chiefly what moves your cost. Where the car is counts too, and whether a technician can safely get to it, after the proportion of petrol to what that tank holds.
What went in, how much, and whether it's run — three questions our engineers ask before quoting, not after, for precisely that reason. A range turns into a straight figure when the answers are in.
About Weston Turville itself
Weston Turville is a village in Buckinghamshire, situated on the banks of the River Thame at an elevation of around 100 metres. Weston Turville has a mix of old and new housing, with detached homes being the predominant type, and is divided into areas such as West End, Church End, and Brook End. Weston Turville is located near the city of Milton Keynes, approximately 17.5 miles away, and is about 33.5 miles from London. Weston Turville has a population of around 1468 residents.
Weston Turville and Buckinghamshire: where our fuel drain cover reaches
The teams answering petrol in diesel calls in Weston Turville, in the HP postcode area, equally work the places around it, West End, Church End and Brook End included. No need to move your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations we drain.
Still at the petrol pump around Weston Turville?
Then you're in the best position there can be. Leave it switched off, then ring.