Petrol in a Diesel Car in Mortimer: How Worried Should You Be?
Likely less than you already are — provided no one has started the car. Petrol resting in a diesel tank does nothing to the engine till something draws it through your fuel system — the ignition priming your pump, the starter, or the drive itself. So the honest answer to the first question everyone around Mortimer asks, "have I wrecked it?", is generally no. Keep it that way: leave the motor off and phone Petrol in Diesel. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and ways to make sure you don't repeat it.
Petrol in a diesel: what does it do to the motor?
On its way through a motor, diesel has two tasks. Oiling comes before burning; it does both. Extremely fine clearances go into the injectors and your high-pressure pump, and just your diesel flowing through keeps those surfaces from grinding together.
Petrol does the first job poorly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump running on the blend to wear itself. It is equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the knocking.
Combined, those make the shape of the issue clear. The harm is done by movement, not by contact. Petrol in a tank 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 that petrol is where a mechanical problem starts.
How serious is petrol in a diesel? Four situations our engineers see in Mortimer
Filled but never started — as good as it gets. Only that tank has petrol in it, and so the job is draining that tank and cleaning your system where your car stands. This situation can only really occur on a forecourt: anywhere else, the car got there by being driven.
Started for a moment, or just your ignition on. The fuel system has been primed, and so petrol has left the tank and got to your filter and the fuel lines. That's normally still an easy task — a drain, a flush, and the fuel filter seen to.
A few miles driven, and your pump has spent every one of them running on weakened fuel. The work is your tank, the lines, your filter and fresh fuel through the entire system, and how hard the car was driven matters as much as how far. A school run to Mortimer St. John's C.E. Infant School is one matter. Very different a second time: a run to Winchester, under 25 miles away, or any miles on the M4, under 5 miles from Mortimer, where your engine never stopped labouring hard.
Driven till it protested. Clattering, a lumpy idle, smoke, a throttle that has gone soft. The fuel isn't behaving like diesel any more, and your engine is saying so. Stop where you are — on the verge on King Street, at the kerb, down a side road — and do not move it again. A car stopped quickly very rarely has permanent damage, as the drain and the flush-through, which still come first, take care of it.
Mortimer drivers and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Topping up removes nothing; it gives you a bigger tank of the same mixture. The assumption behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A current diesel can cope with a bit of petrol." At higher pressure, through smaller components: that's how a modern diesel handles its fuel, and so the lubrication matters for more, not less.
The myth that catches drivers out: if it starts and drives, it must be unharmed. Feed diesel to a petrol motor and it normally will not run, so the driver stops — and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile your pump wears. Running does not mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an old fix for a distinct problem. None of what petrol thinned gets put back by it — and later, the tank still holds that petrol.
The next start draws petrol back round the pump out of your lines and your filter, where some of it ends up after your engine has been run. That's why a DIY tank drain does not leave you sorted — a myth. Clearing petrol into a can at the roadside is also genuinely dangerous.
Why petrol in a diesel takes place at all
On purpose? Never. Through carelessness? Seldom, if ever. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle generally won't go into a petrol car at all. So the error runs one way.
When routine and the car stop matching, it happens. Hire cars, courtesy cars, and cars that are new to you. One petrol and one diesel on the driveway of the same household. Your usual forecourt, its pumps suddenly in a different order. Racing for a train at the nearest station and filling up en route. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it has always done.
Mortimer people: how to prevent petrol in a diesel next time
- The label is what matters, so check the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- Check the filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on your first fill in a vehicle you do not know.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a home with one of each.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It sounds silly and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so put your phone away then keep your mind on the pump.
- Add-on devices exist for cars without one, and some diesels come with a filler that will not accept a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label.
- Stop as soon as you notice. Less petrol inside that tank makes a thinner mixture. It does not change what to do next, which is still not to crank it.
Mortimer: already put petrol in a diesel?
Then the order of things is brief. Leave it unstarted, with your ignition off too. Ask the staff to help you push it clear of the pump if you are still at the forecourt, whether that's Esso or somewhere else. What went in, roughly how much, and whether it's run: tell us those when you phone 0333 366 0103.
If it was AdBlue instead of petrol, say so. That is a separate issue — corrosion and deposits rather than lost protection — and it has its own page for Mortimer.
What makes one Mortimer petrol in a diesel task cost more than the next
There's no honest single price for this, because the four situations above are four different jobs. The scenario itself does most of the work of moving your cost. The share counts next, meaning how much of that tank is petrol, and then the position of the vehicle and whether reaching it is safe for a van.
Before any quote, not after, we ask three queries: your fuel that went in, the amount, and whether it's run. That is why. The replies change a range into a straight figure.
About Mortimer, for a moment
Mortimer is a village in Berkshire, situated in the inland countryside of South East England, with an elevation of around 96 metres. Mortimer lies approximately 41 miles west of London and 24 miles north of Winchester, near the smaller settlements of Summerlug and Four Houses Corner. Mortimer has a population of around 2323 people, predominantly living in detached houses. Mortimer is also closely associated with the nearby village of Stratfield Mortimer.
Fuel drain cover in Mortimer and across Berkshire
Our vans answering petrol in diesel call-outs in Mortimer, in the RG postcode area, also work the places around it, Summerlug, Four Houses Corner and Stratfield Mortimer included. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our engineers work, and your car doesn't need to move to us.
Mortimer: still at the pump?
Then you are in the best spot there can be. Keep it off. Call.