Glencorse: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less anxious than you probably are. "Have I wrecked it?" is the first question everyone in Glencorse asks, and the honest answer is usually no, because petrol left in a diesel tank harms nothing till it is dragged through the system — by ignition priming, by your starter, or by driving. To keep it that way, phone Petrol in Diesel then leave your engine alone. The rest of this page covers what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
Inside the engine: what petrol in a diesel really does
On its way through an engine, diesel does two jobs. It ignites, and before it burns it lubricates. The high-pressure pump and the injectors are designed to very fine tolerances, and your diesel passing through them is what keeps those surfaces from wearing down against each other.
Of these two jobs, petrol manages the first poorly and the second never. The knocking comes from petrol being made not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips out the lubrication the fuel system hinges on, and any pump working on that mix is wearing itself.
Taken together, they make clear the shape the problem takes. It's movement that does the harm, not contact. Petrol in a tank is a fuel problem. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the fuel injectors further on.
Petrol in a diesel around Glencorse: how bad is it? Four situations
The best case there can be: filled up, not once started. The petrol is in the tank and only your tank, and the task is a drain and a flush where your car stands. This is the one situation that can only truly occur on a forecourt, because anywhere else the vehicle has been driven to get there.
Started for a moment, or just your ignition on. Once primed, the system has drawn petrol out of your tank up to your filter and your lines. Usually nothing more than emptying, cleaning and sorting the filter, so still easy.
A few miles driven, and the pump has spent every one of them labouring on weakened fuel. How hard your car was driven matters as much as how far, and this work takes in your tank, the fuel lines, the filter and fresh fuel through the whole system. Short trips, like the school run to the local primary school, are one matter. Any distance on the M8, under 10 miles from Glencorse, means the engine has worked hard throughout, and a run to Edinburgh, under 10 miles away, makes a very different task as well.
Driven until it complained. Knocking, a lumpy idle, smoke, a throttle that has gone soft. The engine is telling you the fuel is no longer acting like diesel. Pull up wherever you are — the verge on Balfour Terrace, a lay-by, a side street — then leave the vehicle where it is. Long-term damage is very unusual if a vehicle is pulled over early, and the fuel drain and flush-through that still come first deal with it.
Glencorse motorists 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." Nothing is removed when you top up — that tank just holds more of the same mixture. That guidance assumes a diesel fuel system handles petrol by percentage. It doesn't.
"Newer diesels can handle a little petrol" — a myth, and nearer the reverse. A newer diesel sends its fuel through smaller parts at higher pressure, which makes the protection matter more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that catches motorists. The driver of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the harm stops there. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile the pump wears. Being able to run is not the same as being fine.
Not so: a two-stroke additive lets you to drive home. It is an old workaround, meant for another issue. The petrol is still in your tank afterwards, and whatever it has thinned is not put back.
If the motor has run, part of that petrol sits in the filter and the lines, not that tank — and your next start sends it right back through your pump. So the myth "drain that tank yourself and you're sorted" does not hold. It's also really risky to drain petrol into a can at the roadside.
How it happens: petrol in a diesel
It is seldom carelessness, and nobody does it on purpose. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle mostly will not go into a petrol car at all. So the error runs one way.
When routine and your car stop matching, it occurs. A new car, a hire car or a courtesy car. Households running one of each, petrol and diesel. Your normal forecourt, its pumps suddenly in a different order. A train to catch, and a rushed fill en route to Newtongrange. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. Throw in a back seat full of kids, a phone call or rain, and habit takes over.
Preventing petrol in a diesel next time you fill up around Glencorse
- Check the pump, not the colour. In the UK unleaded handles are usually green and diesel black, yet not on every forecourt. The label is what counts.
- The first fill in a strange car is the time to check the filler flap — on it, or on the cap, many motors state which fuel they take.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key when a house has one of each. So mark it.
- Before the nozzle comes off the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Daft, yes, yet it does the trick.
- Put the phone away. This is an easy mistake to make whilst you are thinking about something else.
- Some diesels have a filler built to block a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- As soon as you realise, stop: less petrol in that tank means a thinner mix. What to do next does not change, though — still don't start the car.
Petrol already in a diesel around Glencorse? Begin here
Then the order of things is short. Starting it is out, and so is switching on your ignition. If you're still at the forecourt — Tesco or anywhere else — ask the staff to help you roll the vehicle clear of the petrol pump. Then ring 0333 366 0103 and tell us what was put in, roughly how much, and whether it's run.
If it was AdBlue instead of petrol, say so. That's a different fault — corrosion and deposits instead of lost protection — and it has its own page for Glencorse.
One petrol in a diesel job around Glencorse costs more than another. Why?
A fair single quote does not exist here: four scenarios, four separate jobs. Mostly, the cost shifts with which one you're in. Two things come after that: the petrol that got in as a share of what that tank holds, then the spot the car is in and whether our van can reach it safely.
What was put in, how much, and if it's run — three queries our technicians ask before quoting, not after, for precisely that reason. Those replies are what turn a range into one firm number.
About Glencorse itself
Glencorse is a suburban area situated on the riverside in Midlothian, with a mix of semi-detached housing and other residential properties. Glencorse sits at an elevation of 172 metres, close to the nearby settlements of Auchendinny and Beeslack. Glencorse is located near the larger town of Milton Bridge and is approximately 7.5 miles from Edinburgh, the capital city of Scotland. Glencorse has a population of around 1904 residents.
Fuel drain cover across Midlothian, Glencorse included
Petrol in diesel call-outs around Glencorse — part of the EH postcode area — go to vans that likewise cover the locations round it, Auchendinny, Beeslack and Milton Bridge among them. You need not bring your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations where we work.
At the petrol pump around Glencorse, right now?
The best position there is, then — that is where you are. Keep it off. Ring.