Petrol in a Diesel Car in Theescombe: How Worried Should You Be?
Likely less than you are now — as long as no one has started the car. Till the ignition primes the pump, the starter cranks, or the car is driven, petrol in a diesel tank simply sits there and does no harm. Which makes the truthful reply to the first Theescombe question — "have I ruined it?" — normally no. To keep the vehicle that way, phone Petrol in Diesel then leave the motor switched off. What petrol really does to a diesel, how to gauge how far it's travelled, and how to stop it from happening a second time: that's the rest of this page.
Petrol in a diesel: what does it do to your engine?
Passing through an engine, diesel does two things at the same time. It lubricates to begin with, and only then does it burn. The high-pressure fuel pump and your injectors are built to very fine tolerances, and your diesel passing through them is what stops those surfaces from grinding against each other.
Poorly at the first, not at all at the second: that's petrol. A pump working on a petrol mixture is wearing itself out, since petrol is runnier than diesel and strips out the lubrication the fuel system depends on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that is where the clattering comes.
Put those together and the shape of the problem is clear. It's movement that causes the harm, not contact. All a tank with petrol in it amounts to is a fuel issue. The beginning of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with the fuel to the fuel injectors downstream.
Four situations our technicians see around Theescombe: how serious is petrol in a diesel?
Fuelled up, not once started. The best case there is. At a forecourt, and genuinely only there, that petrol is still confined to your tank — because anywhere else the vehicle was driven to reach it. The task is emptying and purging on the spot.
The ignition switched on, or a short start. Once primed, the fuel system has drawn petrol from the tank up to the fuel filter and the fuel lines. That is normally still a straightforward task — a drain, a flush, and the filter seen to.
Driven a couple of miles. Now your pump has spent these miles labouring on diluted fuel. Mileage is only half of it; how hard it was driven counts equally. Either way this work runs to that tank, the lines, your filter and clean fuel through the entire circuit. The school run to Amberley Parochial School is one matter. Any distance on the M5, under 10 miles from Theescombe, means the motor working hard throughout, and a run to Gloucester, under 15 miles away, makes a very different job as well.
Driven till it complained. Clattering, a ragged idle, smoke, a throttle that has gone soft. The fuel is not behaving like diesel any more, and the motor is telling you. Pull up where you are — on the verge on Gydynap Lane, at the kerb, down a side road — and do not move it again. The drain and flush-through still go first, and they take care of it: if a car is pulled over quickly, lasting damage is very unusual.
Theescombe drivers and the petrol in a diesel stories they hear
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. A diesel fuel system does not accept petrol by percentage in the way that advice assumes.
Myth: a newer diesel copes with a bit of petrol. If anything, the opposite. Finer components and higher pressure are how a current diesel runs its fuel, and that makes the lubrication count more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there is no harm done." Diesel in a petrol motor usually means a motor that won't run: the driver stops, and so does the harm. Feed petrol to a diesel and it usually starts, idles and pulls away as if nothing has happened — all while its pump is wearing. A running engine doesn't mean fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, meant for another issue. None of what petrol weakened gets put back by it — and afterwards, that tank still contains that petrol.
"Drain it yourself and you are sorted" — a myth, since after it has been running some petrol sits in the filter and lines, ready to go straight back through your pump on the next start. Also, a can of petrol filled by the roadside is truly dangerous.
How it happens: petrol in a diesel
A careless moment is seldom the cause, and no one means to do it. A diesel nozzle mostly won't go into a petrol car, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error simple, and just in that direction.
When habit and the car stop matching, it happens. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. Your usual forecourt, its pumps suddenly in a different order. Racing for a train outside Stroud and fuelling up en route. A new-to-you diesel Renault Clio, its first fuelling, and a driver accustomed to petrol: exactly when it happens. Add a back seat full of children, a phone call or rain, and the hand wins.
How to prevent petrol in a diesel on your next fill-up in Theescombe
- Green for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Trust the label on the petrol pump, not the colour.
- In a car you don't know, look inside the flap over your filler or at the cap before your first fill: many motors print the fuel there.
- Mark the key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- Before the nozzle leaves the pump the first time you fill a hired or new car, say "diesel" aloud. Daft, perhaps, but it works.
- Mistakes like this are simple to make while your mind is on something else, and so the phone goes away.
- Add-on devices are available for vehicles without one, and some diesels are built with a filler that won't take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- The moment you realise, stop: less petrol in your tank means a thinner blend. What to do next does not change, though — still don't start the vehicle.
Put petrol in a diesel in Theescombe already?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition off as well. Ask the staff to help you roll it away from the pump if you're still at the forecourt, whether that is Shell or anywhere else. What went in, about how much, and if it has run: tell us those when you phone 0333 366 0103.
Say so if it was AdBlue instead of petrol: it is a separate problem, with its own page for Theescombe, because AdBlue brings corrosion and deposits instead of lost protection.
One petrol in a diesel task around Theescombe costs more than another. Why?
An honest single quote does not exist here: four situations, four separate jobs. The situation itself does most of the work of moving the cost. After that it is the ratio — how much petrol went in against how much that tank holds — and then where the vehicle is and whether a van can reach it safely.
Ahead of any quote, not after, we ask three questions: the fuel that went in, the amount, and if it's run. That is why. A range turns into a straight figure when the replies are in.
About Theescombe itself
Theescombe is a village in Gloucestershire, situated on the riverside at an elevation of 118 metres, with detached housing being the predominant type of accommodation. Theescombe lies near the city of Gloucester, approximately 10.7 miles away, and is also close to nearby places such as Amberley and Littleworth. Theescombe has a population of around 609 people and is located in the South West region of England, about 91 miles from London. Theescombe is part of a wider rural area with a mix of agricultural land and residential communities.
Theescombe and Gloucestershire: where our fuel drain cover runs
Amberley, St Chloe and Littleworth are among the spots around Theescombe that the same vans work, answering petrol in diesel jobs across Theescombe's GL postcode area. The vehicle does not need to move to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Theescombe: still at the pump?
Then, you could not be in a better position. Turned off it stays; then phone.