South Pill: Petrol in a Diesel Car? How Worried to Be
Likely less than you already are — provided no one has started it. Till the ignition primes the pump, your starter turns, or your car is driven, petrol in a diesel tank just rests there and does no harm. Which makes the truthful reply to that first South Pill question — "have I ruined it?" — normally no. Petrol in Diesel is who to call, with the engine left off, and so it stays that way. Keep reading for three things: the effect petrol has inside a diesel motor, the clues of how far it has spread, and the way to make sure you don't repeat it.
Inside the motor: what petrol in a diesel really does
Two jobs fall to diesel on its route through a motor. It lubricates first, and only then does it burn. What stops the surfaces inside your high-pressure pump and the injectors from grinding against each other is the diesel flowing through them — they are made to very fine clearances.
Of these two jobs, petrol handles the first badly and the second never. The rattling comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication the system hinges on, and any pump running on that blend is wearing itself.
Seen together, they make clear the shape the trouble takes. The harm is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel fault. Whatever a worn pump sheds travels on, borne by your fuel, into your injectors further along, which is why a pump that has worked on that petrol is where a mechanical issue starts.
Petrol in a diesel around South Pill: how serious is it? Four cases
Filled but not once started — the best it gets. The petrol is in the tank and just the tank, and the task is a drain and a flush where the car sits. This is the one scenario that can only truly occur at a forecourt, because anywhere else your car has been driven to get there.
Your ignition switched on, or a brief start. The fuel system has been bled, so petrol has left the tank and reached the filter and your lines. Drain, flush, deal with your filter: still usually straightforward.
Driven a couple of miles. Now your pump has spent those miles labouring on weakened fuel. The work is that tank, the fuel lines, the filter and fresh fuel through the entire system, and how hard the vehicle was driven counts as much as how far. Driving the kids to Brunel Primary & Nursery Academy is one sort of trip. A run as far as Plymouth, under 5 miles away, is a very different job. So is any mileage on the M5, under 50 miles from South Pill, where your engine has been running hard throughout.
Driven on till it complained — knocking, smoke, a lumpy idle, a dead throttle. The fuel is not behaving like diesel any more, and the motor is saying so. Whether it is the verge on New Road, a lay-by or a side road, stop where you are then leave it. What goes first is still the drain and flush, and that sorts it out, with lasting damage very unusual if a car is stopped soon.
What South Pill people get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Topping up removes nothing; it gives you a bigger tank of the same mix. Percentage isn't how a diesel fuel system copes with petrol, whatever that guidance assumes.
"Newer diesels can handle a little petrol" — a myth, and closer to the opposite. A newer diesel sends its fuel through more precise parts at higher pressure, which makes the lubrication count more, not less.
One myth that catches people 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 damage stops there. A diesel fed petrol normally starts, idles and drives away as if nothing has happened, while your pump grinds. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the car home." It is an outdated workaround for a separate fault. It doesn't put back what petrol has diluted, and that petrol is still in that tank later on.
The next start draws petrol back round the pump out of the lines and your filter, where some of it sits once your engine has been run. That is why a DIY tank drain doesn't sort it — a myth. Clearing petrol into a can at the roadside is also really hazardous.
How it happens: petrol in a diesel
A careless moment is seldom the cause, and nobody means to do it. One way only, because of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one mostly won't fit a petrol vehicle. That's how the forecourt makes it easy.
Habit and your car falling out of step is when it takes place. Hire cars, courtesy cars, and vehicles that are new to you. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. Rushing for a train at Saltash and filling up en route. The first fill-up in a diesel Volkswagen Passat after years of driving petrol is precisely the moment it takes place. Add a back seat full of kids, a phone call or rain, and habit wins.
South Pill drivers: how to prevent petrol in a diesel next time
- The label is what counts, so check the petrol pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- Check the filler flap. Plenty of cars state the fuel type inside the flap or on the cap. Look at it on the first fill in any motor you don't know.
- Good intentions do less than a sticker or a fob in a bright colour on the diesel's key when a household has one of each. So label it.
- Before the nozzle leaves the petrol pump the first time you fuel a hired or new motor, say "diesel" aloud. Daft, perhaps, yet it works.
- While you are thinking about something else, this is an easy mistake to make — so put your phone away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to refuse a petrol nozzle, and add-on devices exist for the remainder. Treat it as a safety net, then keep checking the petrol pump.
- Less petrol makes a thinner mixture, and so stop the moment you notice — while remembering that the next stage is unchanged. It's still not to crank it.
Put petrol in a diesel around South Pill already?
The order of things is brief, then. Do not turn the ignition on, and do not fire it up. Yet on the forecourt, at Shell or anywhere else? Ask the attendants to help you push the car clear of the pump. Ring 0333 366 0103 next, with three facts — your fuel, the rough volume, and whether it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate problem — South Pill has a page just for it.
South Pill petrol in a diesel jobs: why one costs more than another
A fair single price does not exist here: four situations, four separate jobs. Mostly, the cost shifts with which situation you are in. The proportion matters next, meaning how much of your tank is petrol, followed by the position of the car and whether reaching it is safe for a technician.
What got in, how much, and whether it's run — three queries our engineers ask before pricing, not after, for exactly that reason. Their answers are what change a range into one firm number.
About South Pill itself
South Pill is a suburban area located on the coast of Cornwall, situated near the city of Plymouth and close to the nearby towns of Saltash and St Stephens. South Pill has a population of around 5631 people and is characterised by its predominantly detached housing stock. South Pill sits at an elevation of 38 metres, overlooking the surrounding coastal landscape. South Pill is also within commuting distance of major cities, with London approximately 193 miles away.
Fuel drain cover around South Pill and across Cornwall
Petrol in diesel calls in South Pill — part of the PL postcode area — go to teams that also cover the locations round it, Saltash, Wearde and St Stephens included. No need to move your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
South Pill: still at the pump?
Nothing beats it: that's where you now are. Keep it off. Ring.