West Hill: Petrol in a Diesel Car? How Worried to Be
Likely less than you already are — as long as nobody has started the car. "Have I ruined it?" is the first question anyone in West Hill asks, and the honest answer is normally no, because petrol resting in a diesel tank harms nothing till it is dragged through your fuel system — by ignition priming, by the starter, or by driving. Petrol in Diesel is who to call, with the engine left off, and so it stays that way. The remainder of this page explains what petrol really does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
Inside your engine: what petrol in a diesel does
Passing through an engine, diesel does two jobs at the same time. It protects first, and only then does it burn. Designed to very fine tolerances, the fuel injectors and the pump depend on the diesel moving through them to keep their surfaces from wearing against one another.
The second job petrol does not do at all, and the first it does badly. A pump running on a petrol blend is wearing itself out, since petrol is runnier than diesel and takes away the protection your fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that's where the rattling starts.
The shape of the problem is plain when you put those together. Contact doesn't do the harm — circulation does. Where that petrol is only in the tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds travels on, borne by the fuel, into the injectors further along, which is why a pump that has worked on that petrol is where a mechanical issue begins.
West Hill, petrol in a diesel: four situations, from mild to significant
The best case there is: filled up, never started. At a forecourt, and really only there, that petrol is still limited to the tank — since everywhere else the car was driven to get to it. The task is draining and cleaning on the spot.
A moment's running, or merely your ignition on. With your system primed, your lines and filter now contain petrol that came from that tank. Still generally straightforward: drain, flush, and your filter seen to.
Driven a couple of miles. Now the pump has spent these miles labouring on thinned fuel. How hard the vehicle was driven counts as much as how far, and this work takes in the tank, the lines, the filter and fresh fuel through the whole circuit. On the school run to Western Church of England Primary School, the miles is small. A run as far as Winchester, under 3 miles away, is a very different job. So is any distance on the M3, under 3 miles from West Hill, where your engine has been running hard the whole time.
Driven until it complained. Clattering, an uneven idle, smoke, a throttle that has gone soft. That's the motor telling you its fuel has stopped behaving like diesel. Stop on the spot — on the verge on Nightingale Park, at the kerb, down a side road — and don't move it. Long-term damage is very uncommon when a vehicle is pulled over soon, and the fuel drain and flush-through that still come first take care of it.
Petrol in a diesel stories West Hill motorists hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Topping up takes out nothing; it gives you a bigger tank of the same mixture. Percentage is not how a diesel fuel system tolerates petrol, however much that guidance assumes.
If anything, the opposite holds. Myth: "A current diesel can cope with a bit of petrol." Protection counts more on current diesels, not less, since their fuel passes through finer components at higher pressure.
This is the one that fools motorists. Myth: "If it starts and drives, there is no harm done." Diesel in a petrol motor usually leaves a motor that won't run: the driver stops, and so does the harm. Whilst the pump grinds, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. A running engine does not mean fine.
An old fix for a different problem lies behind this one. Myth: "Add some two-stroke oil and drive the car home." The petrol is still inside your tank afterwards, and what it has weakened isn't put back.
The next start draws petrol back round your pump from the lines and the filter, where some of it ends up once the motor has run. That is why draining your tank yourself doesn't leave you sorted — a myth. And, a can of petrol filled at the kerbside is genuinely risky.
Why petrol in a diesel occurs at all
A careless moment is seldom the cause, and no one means to do it. One way only, because of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, while the diesel one mostly will not fit a petrol motor. That's how the forecourt makes it simple.
The moment routine stops matching your car is the moment it takes place. Courtesy car, hire car, or a motor that is new. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. Fuelling up in a rush on the way to Winchester, with a train to catch. Years of petrol cars behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that is when. Add a back seat full of children, a phone call or rain, and habit wins.
West Hill motorists: how to prevent petrol in a diesel next time
- Read the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what matters.
- The first fill in a new vehicle is the time to check your filler flap — on it, or on the cap, plenty of vehicles state the fuel they take.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, in a home with one of each.
- 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 seems daft and it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away then keep your mind on the pump.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to refuse a petrol nozzle, and add-on devices are available for the remainder. Treat it as a backstop, then keep reading the pump.
- Less petrol means a weaker blend, and so stop the moment you notice — while remembering that the next stage is unchanged. It is still not to fire it up.
West Hill: already put petrol in a diesel?
Then, there is only a short order of things. Leave it unstarted, with the ignition off too. Ask the staff to help you roll it away from the petrol pump if you're still at the forecourt, whether that's BP or somewhere else. Ring 0333 366 0103 next, with three answers — your fuel, the approximate amount, and whether it's run.
If it was AdBlue rather than petrol, say so. That is a different problem — corrosion and deposits and not lost protection — and it has its own page for West Hill.
Why one petrol in a diesel task in West Hill costs more than another
The four scenarios above are four separate jobs, so no single quote for this would be honest. Which of them you are in is chiefly what moves your cost. Where the car is counts too, and whether a van can safely reach it, after the ratio of petrol to what that tank takes.
Before any quote, not after, come three queries: your fuel that got in, its quantity, and if it has run. That is why. The answers change a range into a straight figure.
About West Hill, for a moment
West Hill is a suburban area situated near the city of Winchester in Hampshire, with a mix of terraced housing and other residential properties. West Hill sits at an elevation of around 109 metres, close to the nearby areas of Sleepers Hill and Fulflood. West Hill is located approximately 1 mile from Winchester city centre and about 60 miles from London. West Hill has a population of around 7251 people, living in a variety of housing types, predominantly terraced.
West Hill and Hampshire: where our fuel drain cover runs
Sleepers Hill, Fulflood and Stanmore are among the spots around West Hill that the same vans work, answering petrol in diesel jobs across West Hill's SO postcode area. A forecourt, a supermarket car park, a lay-by or your own drive are all locations we work, and the car doesn't need to come to us.
West Hill: still at the pump?
In that case, you couldn't be in a better spot. Keep it off. Phone.