Even Swindon: Petrol in a Diesel Car? How Worried to Be
Likely less than you already are — provided no one has started the car. Till your ignition primes your pump, your starter cranks, or your car is driven, petrol in a diesel tank simply waits there and does no harm. Which means the honest reply to the first Even Swindon question — "have I wrecked it?" — normally no. To keep the vehicle that way, call Petrol in Diesel and leave the engine alone. The remainder of this page sets out what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Your engine and petrol in a diesel: what happens
Passing through a motor, diesel is doing two things at the same time. It lubricates first, and only then does it burn. What keeps the surfaces inside the high-pressure fuel pump and your injectors from wearing against one another is the diesel passing through them — they're designed to very fine clearances.
Badly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump running on that mixture to wear itself. It is equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the clattering.
Together, those leave the shape of the trouble plain. Not contact but movement is what causes the harm. A tank with petrol in it is a fuel issue. Whatever a worn pump sheds travels on, carried by the fuel, into your injectors further along, which is why a pump that has been working on that petrol is where a mechanical problem starts.
Four situations our technicians see around Even Swindon: how serious is petrol in a diesel?
The best case there can be: filled up, not once started. Only the tank has petrol in it, and so the task is draining that tank and cleaning your system where your car sits. This scenario can only truly happen at a forecourt: anywhere else, the vehicle got there by being driven.
Ignition on, or started for a moment. Once primed, the system has pulled petrol out of your tank as far as your filter and the lines. That's generally still a simple job — a drain, a flush, and your filter dealt with.
A few miles driven, and the pump has spent every one of them labouring on thinned fuel. Miles is only half of it; how hard it was driven matters equally. Either way this work runs to that tank, the fuel lines, the filter and fresh fuel through the entire system. Short trips, such as the school run to Even Swindon Primary School, are one thing. Very different once more: a trip to Oxford, under 50 miles away, or any mileage on the M4, under 3 miles from Even Swindon, where your engine kept working hard.
Driven till it protested. Knocking, a lumpy idle, smoke, a throttle that has gone soft. The motor is telling you your fuel is no longer behaving like diesel. Stop wherever you are — the verge on Rodbourne Road, a lay-by, a side street — and leave it where it is. A car stopped soon very rarely has permanent damage, because the fuel drain and the flush-through, which still come first, deal with it.
Petrol in a diesel stories Even Swindon people hear
Myth: topping up to full with diesel makes it fine. It does not. Nothing comes out when you top up — that tank simply holds more of the same blend. Percentage isn't how a diesel fuel system tolerates petrol, however much that advice assumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. A newer diesel sends its fuel through smaller parts 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 people. Feed diesel to a petrol motor and it generally won't run, and so the driver stops — and the harm stops with them. Whilst the pump wears, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. A running engine does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate problem. What petrol has weakened stays weakened, and the petrol stays in that tank regardless.
Myth: "Drain your tank yourself and you're sorted." After the motor has run, some of the petrol is no longer in the tank: it is in the fuel filter and your lines, and it goes right back through your pump at the next start. Besides, petrol cleared into a can by the road is truly hazardous.
Why petrol in a diesel takes place at all
Nobody does it on purpose, and it is rarely carelessness. A diesel nozzle generally will not fit a petrol vehicle, but the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake easy, and just in one direction.
Habit and your car getting out of step is how it occurs. Courtesy car, hire car, or a car that is brand new. Two motors on one drive, one petrol, one diesel. The pumps in a different order on a well-known forecourt. Fuelling up in a hurry on the way to Swindon, with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it takes place. Throw in rain, a phone call or a back seat full of kids, and the hand repeats what it has always done.
Preventing petrol in a diesel next time you fill up in Even Swindon
- Check 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.
- In a vehicle you don't know, look inside the flap over your filler or at the cap before the first fill: plenty of cars state the fuel type there.
- One of each in the home? Label your key to your diesel — a coloured fob, a sticker — since meaning to remember is not enough.
- Before the nozzle comes off the pump the first time you fuel a hired or new motor, say "diesel" out loud. Silly, perhaps, yet it does the trick.
- Mistakes like this are easy to make while your mind is on something else, so the phone goes away.
- Some diesels have a filler built to refuse a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the petrol pump.
- As soon as you realise, stop: less petrol in that tank means a thinner blend. What to do next doesn't change, though — still don't fire it up.
Already put petrol in a diesel around Even Swindon?
The order of things is brief, then. Leave it unstarted, with your ignition switched off too. If you are still at the forecourt — Shell or anywhere else — ask the staff to help you roll the car clear of the pump. Next, 0333 366 0103. We'll ask what got in, about how much, and if it has been run.
Say so if it was AdBlue instead of petrol: it's a different fault, with its own page for Even Swindon, because AdBlue brings corrosion and deposits rather than lost lubrication.
Why one petrol in a diesel job in Even Swindon costs more than another
Four separate jobs sit behind the four situations above — which is why there is no fair single quote. Mostly, your cost moves with which situation you are in. Where the car is counts too, and whether a van can safely reach it, after the ratio of petrol to what your tank holds.
Ahead of any quote, not after, we ask three queries: your fuel that went in, its amount, and whether it has run. That is why. The replies change a range into a straight figure.
About Even Swindon itself
Even Swindon is a suburban area situated on the riverside in Wiltshire, with a mix of terraced housing and local amenities. Even Swindon sits at an elevation of 102 metres, close to the nearby places of Kingshill and New Town. Even Swindon is located near the city of Swindon, and is also within commuting distance of Oxford, which is approximately 26 miles away. Even Swindon has a population of around 7376 residents.
Even Swindon and Wiltshire: where our fuel drain cover reaches
Kingshill, New Town and Swindon are among the places near Even Swindon that the same teams work, answering petrol in diesel jobs across Even Swindon's SN postcode area. The vehicle does not need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
In Even Swindon and still at the pump?
The best spot there is, then — that is where you are. Turned off it stays; then phone.