How Worried Should You Be? Petrol in a Diesel Car in Minehead
Probably less than you already are — provided nobody has started the car. "Have I wrecked it?" is the first thing everyone in Minehead asks, and the honest answer is usually no, since petrol resting in a diesel tank hurts nothing till it's dragged through the system — by ignition priming, by your starter, or by driving. Leave the engine off then ring Petrol in Diesel — that keeps it like that. Read on for three things: the effect petrol has inside a diesel engine, the clues of how far it has got, and the way to make sure you don't repeat it.
What petrol in a diesel does to the engine
Diesel does two tasks on its way through a motor. It protects to begin with, and after that does it burn. What stops the surfaces inside your high-pressure pump and the fuel injectors from wearing down against each other is the diesel flowing through them — they're built to extremely fine gaps.
The second task petrol doesn't 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 lubrication your fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where the rattling starts.
Together, those make the shape of the problem clear. Not contact but movement is what causes the damage. A tank with petrol in it is a fuel issue. The beginning of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with the fuel to the injectors beyond it.
Petrol in a diesel around Minehead: how serious is it? Four situations
The best case there can be: filled up, never started. Being at a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With that petrol kept inside your tank alone, it's cleared and cleaned right where it stands, and nothing more is needed.
Ignition on, or started for a moment. With your system primed, the lines and filter already contain petrol that came from your tank. Usually little more than draining, flushing and seeing to the filter, so still straightforward.
Driven a couple of miles. Now the pump has spent these miles labouring on thinned fuel. Distance is only half of that; how hard it was driven matters just as much. Either way the work includes your tank, the lines, the filter and fresh fuel through the entire system. On the school run to St Michael's Church of England First School, the distance is small. A run as far as Cardiff, under 25 miles away, is a very different job. So is any miles on the M5, under 25 miles from Minehead, where the motor has been working hard throughout.
Clattering, a ragged idle, smoke, a throttle gone soft: driven till it complained. That's your motor telling you its fuel has stopped behaving like diesel. Whether it's the verge on Bancks Street, a lay-by or a side road, stop there and leave it. The fuel drain and flush still go first, and they take care of it: if a car is pulled over quickly, lasting damage is very rare.
What Minehead motorists get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. A fuller tank of the same mixture is all it gives, because topping up takes out nothing. That advice assumes a diesel fuel system tolerates petrol by percentage. It does not.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. Finer parts and higher pressure are how a newer diesel runs its fuel, and that makes the lubrication matter more, not less.
"It starts, it drives, so no harm done" — the myth that catches most drivers than any other. Feed diesel to a petrol engine and it generally won't run, and so the driver stops — and the damage stops with them. Feed petrol to a diesel and it usually fires up, idles and drives away as if nothing has happened — all while its pump wears. Fine and running aren't the same at all.
An outdated fix for a different fault lies behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has diluted remains thinned, and the petrol stays inside the tank regardless.
Myth: "Drain your tank yourself and you are sorted." Once your engine has run, some of that petrol is no longer in that tank: it is in the fuel filter and the fuel lines, and it goes right back through the pump on your next start. Emptying petrol into a can by the kerbside is also really risky.
Petrol in a diesel: how does it happen?
On purpose? Never. Through carelessness? Rarely, if ever. One way only, because of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol vehicle. That's how the forecourt makes it easy.
The moment habit stops matching your car is the moment it occurs. A motor that is new to you — hired, on loan as a courtesy car, or brand new. One petrol and one diesel on the drive of the same household. The pumps in a different order on a well-known forecourt. A hurried fill on the way to the nearest station with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. Your hand does what it has always done when you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel on your next fill-up in Minehead
- Read the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on every forecourt. The label is what matters.
- The first fill in an unfamiliar car is the time to check your filler flap — on it, or on the cap, many cars state which fuel they take.
- Good intentions do less than a sticker or a fob in a bright colour on the diesel's key if a home has one of each. So label it.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car gets its first tank. It sounds silly. It works.
- While you're thinking about something else, this is an easy mistake to make — so put your phone away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to reject a petrol nozzle, and add-on devices are available for motors without one. They are a backstop, not a reason to stop checking the pump.
- Stop as soon as you realise. Less petrol inside the tank makes a thinner mixture. It doesn't change what to do next, which is still not to start the vehicle.
Minehead: already put petrol in a diesel?
Then, there is only a short order of things. Don't turn your ignition on, and do not crank it. The staff at the forecourt — whether at Texaco itself or wherever you filled up — will usually help roll it away from the petrol pump if you ask. Then ring 0333 366 0103 and tell us what was put in, about how much, and whether it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different fault — Minehead has a page just for it.
One petrol in a diesel task in Minehead costs more than another. Why?
The four scenarios above are four different jobs, so no single quote for this would be fair. The scenario itself does most of the work of moving your cost. Where the car is matters too, and whether our van can safely reach it, after the ratio of petrol to what that tank takes.
Three questions come first, before quoting, rather than after — what went in, how much, has it run — and this is the reason. The answers change a range into a straight figure.
About Minehead and its setting
Minehead is a coastal town in Somerset, situated on the edge of Exmoor National Park, with a population of around 10,789 people. Minehead sits at a low elevation of 19 metres, looking out over the Bristol Channel, and is characterised by its semi-detached housing stock. Minehead is close to nearby settlements such as Higher Town, Periton, and Alcombe, and is within commuting distance of Cardiff, which is 23 miles away. Minehead is also a significant distance from London, at 146 miles away.
Minehead and Somerset: where our fuel drain cover runs
Petrol in diesel call-outs around Minehead — part of the TA postcode area — go to teams that also cover the places around it, Higher Town, Periton and Alcombe included. The car does not need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the petrol pump around Minehead?
The best place there is, then — that's where you are. Switched off it remains; then ring.