Should You Worry? Petrol in a Diesel Car in Cabbage Hill
Far less than you likely are, provided it hasn't been started. Petrol sitting in a diesel tank does nothing to your motor until something pulls it through the fuel system — the ignition priming your pump, your starter, or the drive itself. So the fair answer to the first query everyone around Cabbage Hill asks, "have I wrecked it?", is normally no. Keep it like that: leave your engine off then phone Petrol in Diesel. Further down, you will find what petrol actually does inside a diesel, how far it might have got, and how to stop it happening to you again.
The motor and petrol in a diesel: what goes on
Diesel has two tasks on its way through a motor. Oiling comes before burning; it does both. Extremely fine clearances are built into the fuel injectors and the high-pressure fuel pump, and only your diesel running through stops their surfaces grinding together.
The second job petrol does not do at all, and the first it does poorly. A pump working on a petrol mixture is wearing itself out, since petrol is runnier than diesel and strips out the protection your fuel system relies on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where any rattling comes.
Put these together and the shape of the problem is plain. Contact doesn't do the damage — circulation does. Any tank with petrol in it is a fuel problem. After the pump has been running on that petrol, a mechanical problem has begun: whatever is shed by a pump that's wearing down is carried onward to your injectors with your fuel.
Four situations our engineers see around Cabbage Hill: how serious is petrol in a diesel?
Filled up, never started. The best case there is. On a forecourt, and genuinely only there, the petrol is still confined to your tank — because everywhere else the vehicle was driven to get to it. The task is emptying and flushing on the spot.
A moment's running, or merely your ignition on. Your system has been primed, so petrol has left the tank and got to your filter and the lines. Still normally easy: drain, flush, and the filter dealt with.
Those few miles driven meant the pump labouring on fuel weakened by petrol the whole way. Miles is only half of it; how hard it was driven counts just as much. Either way the work runs to the tank, the lines, your filter and fresh fuel through the entire system. On the school run to Warfield Church of England Primary School, the miles is small. Any distance on the M4, under 3 miles from Cabbage Hill, means your engine has worked hard throughout, and a run to Westminster, under 50 miles away, is a very different job too.
It protested, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone uneven. That's your engine telling you its fuel no longer is acting like diesel. Pull up wherever you are — the verge on West End Lane, a lay-by, a side street — then leave the car where it is. A car pulled over soon very rarely has permanent damage, as the fuel drain and the flush-through, which still come first, take care of it.
Petrol in a diesel stories Cabbage Hill people hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. That advice supposes a diesel fuel system tolerates petrol by percentage. It doesn't.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. Protection counts more on modern diesels, not less, because their fuel runs through more precise components at higher pressure.
"It starts, it drives, so no harm done" — the myth that catches more motorists than any other. A petrol engine fed diesel generally will not run, and so the driver stops and the harm stops with them. Feed petrol to a diesel and it usually fires up, idles and pulls away as if nothing happened — all while its pump wears. Running doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different problem. The petrol is still inside that tank afterwards, and whatever it has thinned isn't put back.
The next start sends petrol back round your pump out of the lines and the filter, where some of that ends up once your engine has run. That is why draining the tank yourself doesn't leave you sorted — a myth. Besides, petrol cleared into a can by the road is truly risky.
How it happens: petrol in a diesel
It's rarely carelessness, and no one does it on purpose. A diesel nozzle generally won't go into a petrol vehicle, yet the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and only in that direction.
It happens when habit and your car stop matching. Courtesy car, hire car, or a motor that is brand new. Two motors on one drive, one petrol, one diesel. A well-known forecourt with the pumps in a different order. Rushing for a train outside Bracknell and fuelling up en route. A new-to-you diesel Renault Megane, its first fuelling, and a motorist accustomed to petrol: precisely when it takes place. Add rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
Next time you fill up in Cabbage Hill: avoiding petrol in a diesel
- The label is what counts, and so check the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, yet not on each forecourt.
- Plenty of cars state the fuel inside the filler flap or on the cap, so check it on your first fill in any vehicle you do not know.
- Good intentions do less than a sticker or a fob in a bright colour on your diesel's key when a household has one of each. So mark it.
- Before the nozzle comes off the pump the first time you fill a hired or new vehicle, say "diesel" out loud. Silly, yes, yet it works.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away and keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to block a petrol nozzle, and add-on devices exist for motors without one. They are a safety net, not a reason to stop reading the pump.
- Spotting it mid-fill? Stop at once. A thinner mix follows from less petrol in that tank, but the next stage remains the same: do not crank it.
Petrol already in a diesel around Cabbage Hill? Begin here
Then the order of things is short. Don't crank it, and do not switch the ignition on. Ask the attendants to help you roll it away from the pump if you're still at the forecourt, whether that's Esso or anywhere else. What got in, about how much, and if it's run: tell us that when you call 0333 366 0103.
If it was AdBlue instead of petrol, say so. That's a different issue — corrosion and deposits and not lost protection — and it has its own page for Cabbage Hill.
Why one petrol in a diesel task in Cabbage Hill costs more than another
The four scenarios above are four different jobs, so no single quote for this would be honest. What moves your cost is chiefly which of them you're in. Next it's the ratio — how much petrol went in against how much the tank takes — and after that where the car is and whether our van can get to it safely.
What was put in, how much, and whether it's run — three questions we ask before quoting, not after, for precisely that reason. A range turns into a straight figure once the answers are in.
About Cabbage Hill itself
Cabbage Hill is a locality in Berkshire, situated on the riverside at an elevation of 61 metres, with a mix of residential and possibly some commercial properties. Cabbage Hill lies approximately 27.5 miles west of London, near the cities of Westminster and other nearby places such as West End and Newell Green. Cabbage Hill has a population of around 760 people, predominantly residing in flats. Cabbage Hill is part of the wider South East region of England, with nearby areas like Tickleback Row also being residential in nature.
Cabbage Hill and Berkshire: where our fuel drain cover runs
West End, Newell Green and Tickleback Row are among the places near Cabbage Hill that the same teams work, answering petrol in diesel calls across Cabbage Hill's RG postcode area. The car doesn't need to move to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the pump in Cabbage Hill, right now?
Then you are in the best position there can be. Switched off it remains; then ring.