Should You Worry? Petrol in a Diesel Car in Portsmouth
If it has not been started, you can worry far less than you likely are. "Have I wrecked it?" is the first thing everyone in Portsmouth asks, and the truthful answer is generally no, since petrol left in a diesel tank hurts nothing until it is dragged through the system — by ignition priming, by your starter, or by being driven. To keep it like that, ring Petrol in Diesel then leave your engine switched off. Below, this page sets out what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to the motor?
Two tasks fall to diesel on its journey through a motor. Before it ignites, it lubricates — then it burns. Designed to extremely fine clearances, the fuel injectors and the pump depend on your diesel flowing through them to stop their surfaces wearing against one another.
Badly at the first, not at all at the second: that is petrol. A pump running on a petrol mix is wearing itself out, since petrol is runnier than diesel and strips out the lubrication your 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's where the clattering starts.
Seen together, they show the shape the problem takes. It's circulation that does the damage, not contact. All a tank with petrol in it amounts to is a fuel problem. A pump that has been working on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with your fuel to your injectors downstream.
Petrol in a diesel in Portsmouth: how serious is it? Four cases
The best case there is: filled up, not once started. The petrol is in your tank and just the tank, and the job is a drain and a flush where the vehicle stands. This is the one scenario that can only really occur on a forecourt, as anywhere else your car has been driven to get there.
Ignition on, or started for a second. Once primed, your system has pulled petrol out of your tank up to your filter and the lines. Still generally easy: drain, flush, and your filter seen to.
Your pump has spent a few miles on diluted fuel — that is what driving it does. How hard your car was driven matters as much as how far, and the work takes in that tank, the lines, the fuel filter and clean fuel through the entire circuit. Driving the children to Cornholme Junior, Infant and Nursery School is one kind of trip. Very different a second time: a run to Bradford, under 25 miles away, or some mileage on the M65, under 10 miles from Portsmouth, where the engine kept working hard.
Driven until it complained. Clattering, an uneven idle, smoke, a throttle that has gone soft. The fuel isn't behaving like diesel any more, and the motor is saying so. Leave it where it has stopped: a lay-by, a side street, the verge on Carrfield Villas. A vehicle stopped early very rarely has permanent damage, since the drain and the flush, which still go first, take care of it.
Stories Portsmouth drivers hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. A diesel fuel system does not accept petrol by percentage in the way that guidance supposes.
"Modern diesels can handle a little petrol" — a myth, and closer to the opposite. A newer diesel runs its fuel through more precise components at higher pressure, which makes the protection matter more, not less.
One myth that catches motorists off guard: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel normally has no choice but to stop, because it will not run, 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 your pump grinds. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate issue. What petrol has weakened remains weakened, and that petrol remains in that tank anyway.
Myth: "Drain the tank yourself and you're sorted." After the engine has run, some of that petrol is no longer inside your tank: it's in the fuel filter and the fuel lines, and it goes straight back through the pump on your next start. It's also really risky to drain petrol into a can at the kerbside.
Petrol in a diesel: how does it happen?
No one does it on purpose, and it's seldom carelessness. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle generally will not go into a petrol vehicle at all. So the mistake runs one way.
The moment habit stops matching the vehicle is the moment it happens. A vehicle that's new to you — a hire car, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps arranged differently. Filling up in a rush en route to Todmorden, with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is precisely the moment it occurs. The hand does what it has always done once you add rain, a phone call or a back seat full of kids.
Preventing petrol in a diesel next time you fill up around Portsmouth
- A green handle 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.
- Plenty of vehicles state the fuel inside your filler flap or on the cap, and so check there on the first fill in a vehicle you do not know.
- One of each in the home? Mark the key to your diesel — a coloured fob, a sticker — because intending to remember isn't enough.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It sounds daft and it does the trick.
- Whilst you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Add-on devices exist for motors without one, and some diesels are built with a filler that won't take a petrol nozzle. Helpful — but a safety net at best, never a reason to stop checking the label.
- Stop the moment you notice. Less petrol inside the tank makes a weaker mix. It doesn't change what to do next, which is still not to fire it up.
Petrol already in a diesel in Portsmouth? Start here
The order of things is short, then. Don't turn the ignition on, and don't fire it up. If you're still on the forecourt — Shell or anywhere else — ask the staff to help you roll the car away from the pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it's been run.
If it was AdBlue instead of petrol, say so. That is a separate issue — corrosion and deposits rather than lost lubrication — and it has its own page for Portsmouth.
What makes one Portsmouth petrol in a diesel task cost more than the next
Four different jobs sit behind the four situations above — which is why there's no fair single price. Which of them you're in is mostly what moves your cost. Where your car is matters too, and whether a technician can safely reach it, after the ratio of petrol to what the tank holds.
Ahead of any quote, not after, we ask three queries: the fuel that got in, its amount, and if it has run. That is why. Those replies turn a range into a straight figure.
About Portsmouth, briefly
Portsmouth is a suburban area in West Yorkshire, situated on the riverside with a mix of terraced housing. Portsmouth sits at an elevation of 205 metres, overlooking the surrounding landscape. Portsmouth is located near several other communities, including Cornholme, Pudsey, and Shore, and is approximately 16.7 miles from Bradford. Portsmouth is a relatively small residential area, with a population of around 1126 people.
Fuel drain cover around Portsmouth and across West Yorkshire
Petrol in diesel calls around Portsmouth — part of the OL postcode area — go to vans that also cover the spots round it, Cornholme, Pudsey and Shore among them. A forecourt, a supermarket car park, a lay-by or your own drive are all places we work, and the car doesn't need to move to us.
At the petrol pump around Portsmouth, right now?
Then you're in the best spot there can be. Keep it off. Call.