Should You Worry? Petrol in a Diesel Car in Mytchett
Probably less than you are now — as long as nobody has started it. "Have I ruined it?" is the first question everyone around Mytchett asks, and the honest answer is normally no, because petrol left in a diesel tank harms nothing until it is drawn through the system — by ignition priming, by the starter, or by being driven. To keep the car that way, phone Petrol in Diesel then leave your engine switched off. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and the way to make sure you never do it again.
Petrol in a diesel: what does it do to the motor?
Two jobs fall to diesel on its journey round a motor. Before it combusts, it protects — and then it combusts. What stops the surfaces inside your high-pressure pump and the fuel injectors from wearing against one another is your diesel passing through them — they're built to very fine clearances.
Petrol handles the first task poorly and the second not at all. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips out the protection your system rests on, and any pump working on that blend is wearing itself.
Seen together, they make clear what shape the trouble has. The damage is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel problem. Whatever a worn pump sheds goes on, carried by the fuel, into your 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 we see in Mytchett
Filled up, and never started: no case is better. At a forecourt, and genuinely only there, that petrol is still limited to that tank — since everywhere else the vehicle was driven to reach it. The task is emptying and rinsing on the spot.
Ignition on, or started for a moment. With the fuel system primed, the lines and filter now hold petrol that came from that tank. Drain, flush, deal with the fuel filter: still normally simple.
Your pump has worked a few miles on thinned fuel — that's what driving it does. The work is that tank, your lines, the filter and clean fuel through the whole system, and how hard your car was driven matters as much as how far. The school run to Mytchett Primary & Nursery Academy is one thing. A run as far as Westminster, under 50 miles away, is a very different job. So is any miles on the M3, under 3 miles from Mytchett, where the engine has been running hard throughout.
Driven on until it complained — clattering, smoke, a ragged idle, a dead throttle. The motor is telling you your fuel is no longer behaving like diesel. Leave it where it has stopped: a lay-by, a side street, the verge on Mytchett Road. The fuel drain and flush-through still go first, and they deal with it: if a car is pulled over early, permanent damage is very unusual.
Mytchett drivers and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Topping up takes out nothing; it gives you a bigger tank of the same mixture. That guidance supposes a diesel fuel system handles petrol by percentage. It doesn't.
If anything, the opposite is true. Myth: "A modern diesel can cope with a bit of petrol." Smaller components and higher pressure are the way a modern diesel runs its fuel, and that makes the lubrication matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no harm done." A petrol motor fed diesel usually will not run, and so the driver stops and the harm 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 the pump wears. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate problem. What petrol has weakened stays thinned, and the petrol stays inside the tank regardless.
Once the engine has been run, part of that petrol is in the filter and your lines, not the tank — and the next start sends it straight back through the pump. So the myth "drain the tank yourself and you're sorted" does not stand up. It is also genuinely risky to drain petrol into a can by the roadside.
Petrol in a diesel: how does it occur?
Carelessness is rarely the cause, and no one means to do it. A diesel nozzle mostly will not fit a petrol motor, yet the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and only in one direction.
It happens when routine and the car stop matching. Courtesy car, hire car, or a car that is new. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps laid out differently. Filling up in a hurry on the way to North Camp, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist used to petrol: exactly when it occurs. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
Preventing petrol in a diesel next time you fill up in Mytchett
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Check the petrol pump's label; the colour is only a clue.
- Check the filler flap. Plenty of vehicles state the fuel type inside the flap or on the cap. Look at it on the first fill in a vehicle you do not know.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key when a household has one of each. So mark it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It seems silly and it works.
- While you are thinking about something else, this is an easy mistake to make — so put your phone away.
- Add-on devices are available for cars without one, and some diesels come with a filler that will not take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- As soon as you realise, stop: less petrol inside your tank makes a thinner blend. What to do next doesn't change, though — still do not fire it up.
Mytchett: already put petrol in a diesel?
The order of things is short, then. Don't turn the ignition on, and don't fire it up. Ask the staff to help you roll it away from the pump if you are still on the forecourt, whether that's BP or anywhere else. Next, 0333 366 0103. We'll ask what went in, roughly how much, and if it's been run.
Corrosion and deposits form the issue with AdBlue, where petrol brings lost protection. So if it was AdBlue, say so — and see its own Mytchett page.
Why one petrol in a diesel job around Mytchett costs more than another
Four different jobs lie behind the four scenarios above — which is why there is no fair single price. Mostly, your cost shifts with which one you're in. Where the vehicle is counts too, and whether a technician can safely reach it, after the proportion of petrol to what that tank holds.
Before any quote, not after, come three queries: the fuel that got in, the quantity, and whether it's run. That is why. The answers turn a range into a straight figure.
About Mytchett, briefly
Mytchett is a village in Surrey, situated on the riverside at an elevation of 72 metres, with Mytchett being close to the nearby settlements of Mytchett Place and South Farnborough. Mytchett has a population of approximately 1896 residents, with Mytchett predominantly consisting of detached housing. Mytchett is located near Farnborough Park, and Mytchett is about 29.9 miles from London.
Fuel drain cover around Mytchett and across Surrey
Mytchett rests in the GU postcode area, and the teams that answer petrol in diesel call-outs there work the places near it as well — Mytchett Place, South Farnborough and Farnborough Park among them. The car 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 driveway.
At the petrol pump in Mytchett, right now?
No position is better: that's where you now are. Ring, and leave it switched off.