Petrol in a Diesel Car in Crowthorne: How Worried Should You Be?
If it hasn't been started, worry far less than you probably are. Petrol sitting in a diesel tank does nothing to the motor till something draws it through the fuel system — the ignition priming the pump, your starter, or the drive on its own. So the fair answer to the first question everyone in Crowthorne asks, "have I ruined it?", is normally no. Petrol in Diesel is who to phone, with your motor kept off, so it stays that way. Keep reading for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and the way to make sure you never do it again.
Inside the engine: what petrol in a diesel really does
On its way through a motor, diesel has two tasks. Before it combusts, it protects — and then it burns. What keeps the surfaces inside your high-pressure pump and the fuel injectors from wearing down against one another is the diesel passing through them — they are made to extremely fine clearances.
Petrol handles the first task badly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump on that mixture wearing itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the knocking.
Combined, those leave the shape of the problem clear. It is movement that does the harm, not contact. Where the petrol is only inside that tank, it is a problem of fuel, nothing more. Whatever a worn pump sheds travels on, borne by the fuel, into the fuel injectors further along, which is why a pump that has been working on the petrol is where a mechanical fault begins.
How bad is petrol in a diesel? Four situations we see around Crowthorne
Fuelled up, never started. The best case there is. Only that tank has petrol in it, so the job is clearing that tank and purging the fuel system where the car stands. This situation can only really take place on a forecourt: anywhere else, your car got there by being driven.
Ignition on, or started for a moment. Petrol has left that tank and got to the filter and the lines, since your system has been bled. That's usually still a simple task — a drain, a flush, and the fuel filter dealt with.
Driven a couple of miles. Now the pump has spent these miles running on thinned fuel. Tank, lines, filter, then clean fuel run through the entire system: that's this work, and the way the vehicle was driven counts as much as the distance. The school run to Crowthorne Church of England Primary School is one thing. Very different once more: a run to Westminster, under 50 miles away, or some miles on the A329(M), under 3 miles from Crowthorne, where the motor never stopped running hard.
Driven on till it protested — clattering, smoke, a lumpy idle, a dead throttle. The motor is telling you your fuel is no longer acting like diesel. Leave it wherever it stops: a lay-by, a quiet street, the verge on Napier Road. What goes first is still the fuel drain and flush, and that sorts it out, with long-term damage very rare when a vehicle is pulled over soon.
What Crowthorne drivers get told about petrol in a diesel — and the stories in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." A fuller tank of the same mix is all it gives, since topping up removes nothing. The assumption behind the guidance — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the reverse is true. Myth: "A modern diesel can cope with a bit of petrol." Protection counts more on newer diesels, not less, since their fuel passes through finer components at higher pressure.
"It starts, it drives, so no harm done" — the myth that catches most drivers than any other. Feed diesel to a petrol engine and it normally won't run, and so the motorist stops — and the harm stops with them. Feed petrol to a diesel and it normally fires up, idles and drives away like nothing happened — all while its pump is wearing. Fine and running aren't the same at all.
An old workaround for a separate fault is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." That petrol is still in the tank after that, and what it has weakened is not put back.
Myth: "Drain that tank yourself and you're sorted." After the motor has run, some of the petrol is no longer inside that tank: it is in your filter and the fuel lines, and it goes right back through your pump on the next start. On top of that, petrol drained into a can by the road is genuinely risky.
Why petrol in a diesel happens so easily
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle mostly will not go into a petrol motor, but the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and just in that direction.
The moment routine stops matching the vehicle is the moment it takes place. Hire cars, courtesy cars, and cars that are new to you. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. Fuelling up in a rush on the way to the nearest station, with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Passat in front of you at the forecourt for its first tank — that's when. Throw in rain, a phone call or a back seat full of children, and your hand does what it has always done.
Crowthorne drivers: how to prevent petrol in a diesel next time
- Green for unleaded and black for diesel is usual in the UK — but not on each forecourt. Trust the label on the petrol pump, not the colour.
- Inspect your filler flap. Plenty of motors state the fuel inside the flap or on the cap. Look at it on the first fill in any vehicle you do not know.
- Mark the key. In a house with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It seems silly and it does the trick.
- Mistakes like this are simple to make while your mind is on something else, and so your 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 reading the pump.
- Stop the moment you realise. Less petrol in that tank makes a thinner mixture. It does not change what to do next, which is still not to fire it up.
Put petrol in a diesel in Crowthorne already?
The order of things is brief, then. Starting it is out, and so is switching on the ignition. If you are still on the forecourt — BP or anywhere else — ask the attendants to help you push the car away from the petrol pump. Next, 0333 366 0103. We will ask what was put in, about how much, and if it has been run.
Say so if it was AdBlue instead of petrol: it is a separate problem, with its own page for Crowthorne, because AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel job in Crowthorne costs more than another. Why?
Four different jobs lie behind the four situations above — which is why there's no fair single quote. What shifts your cost is chiefly which of them you are in. Beyond that it's the share — how much petrol was put in against how much the tank holds — and after that where your car is and whether a technician can reach it safely.
Before any quote, not after, we ask three queries: your fuel that was put in, its volume, and if it's run. That's why. Their replies are what turn a range into one firm number.
About Crowthorne
Crowthorne is a town situated in the heart of Berkshire, located inland in southeastern England. It forms part of the Bracknell Forest district and is a notable settlement in the area. The town is surrounded by the countryside of Berkshire, offering a rural setting. Crowthorne is a distinct community with its own character.
Crowthorne and Berkshire: where our fuel drain cover reaches
Petrol in diesel call-outs around Crowthorne — part of the RG postcode area — go to teams that likewise cover the places about it, Broadmoor Estate, Ravenswood Village Settlement and Owlsmoor among them. No need to bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots where we work.
Crowthorne: still at the petrol pump?
Nothing beats it: that's where you are. Ring, and leave it turned off.