How Worried Should You Be? Petrol in a Diesel Car in Stone
Not started? Then less anxious than you likely are. Until the ignition primes the pump, the starter cranks, or the car is driven, petrol in a diesel tank simply rests there and does no harm. Which means the truthful reply to the first Stone query — "have I ruined it?" — usually no. Keep it like that: leave the engine off then phone Petrol in Diesel. The remainder of this page sets out what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Your engine and petrol in a diesel: what happens
Passing through an engine, diesel does two jobs at once. Before it ignites, it protects — then it ignites. Extremely fine tolerances are built into your injectors and the high-pressure pump, and just the diesel running through keeps their surfaces from grinding together.
Poorly at the first, not at all at the second: that's petrol. The clattering comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the protection your system rests on, and any pump running on such a mix is wearing itself.
Combined, those make the shape of the problem clear. Not contact but movement is what does the damage. Petrol in the tank is a fuel fault. The beginning of a mechanical problem is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with your fuel to your injectors beyond it.
Stone, petrol in a diesel: four cases, from mild to serious
The best case there is: filled up, not once started. Being on a forecourt is what makes this the case: elsewhere, the vehicle has been driven there to begin with. With that petrol held in your tank alone, it is drained and rinsed right where it stands, and nothing more is needed.
The ignition switched on, or a brief start. Once primed, the fuel system has pulled petrol out of that tank up to the fuel filter and your lines. Normally nothing more than draining, cleaning and seeing to your filter, and so still simple.
Your pump now spent a few miles on thinned fuel — that's what driving it does. How hard the car was driven counts as much as how far, and this work takes in the tank, your lines, the filter and fresh fuel through the whole circuit. Short trips, such as the school run to St Dominic's Catholic Primary School, are one thing. Any mileage on the M6, under 3 miles from Stone, means your engine has worked hard throughout, and a run to Stoke-on-Trent, under 10 miles away, is a very different task as well.
Clattering, an uneven idle, smoke, a throttle gone soft: driven till it complained. The fuel isn't acting like diesel any more, and your motor is telling you. Leave it wherever it stops: a lay-by, a quiet street, the verge on Lichfield Street. What goes first is still the drain and flush-through, and that deals with it, with permanent damage very rare if a car is stopped soon.
Petrol in a diesel myths Stone people hear
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 bigger tank, still the same mixture. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance supposes.
Not so: a newer diesel copes with a bit of petrol. Rather, the opposite. At higher pressure, through smaller components: that is how a newer diesel handles its fuel, so the protection matters for more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that catches people. The motorist of a petrol engine fed diesel normally stops, because it will not run, and the harm stops with them. Feed petrol to a diesel and it normally fires up, ticks over and pulls away as if nothing happened — all while its pump wears. Fine and running are not the same thing.
Myth: a two-stroke additive makes it safe to drive home. It is an old fix, meant for another fault. None of what petrol thinned is put back by it — and later, the tank still holds the petrol.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol lies in the filter and lines, ready to go straight back through your pump at the next start. It's also really dangerous to drain petrol into a can by the kerbside.
Petrol in a diesel: how does it occur?
It is rarely carelessness, and nobody does it on purpose. The forecourt makes it simple: the petrol nozzle is the slimmer of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle generally won't go into a petrol vehicle at all. So the slip runs one way.
Routine and the vehicle getting out of step is how it happens. Courtesy car, hire car, or a motor that's new. One petrol and one diesel on the driveway of the same household. The pumps in a different order on a familiar forecourt. A train to catch, and a hurried fill en route to the nearest station. A new-to-you diesel Volkswagen Passat, its first fuelling, and a driver accustomed to petrol: exactly when it takes place. Throw in rain, a phone call or a back seat full of kids, and your hand does what it has always done.
Next time you fill up around Stone: avoiding petrol in a diesel
- Read the 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.
- In a motor you don't know, look inside the flap over your filler or at the cap before your first fill: many cars state the fuel there.
- One of each in the home? Mark the key to the diesel — a coloured fob, a sticker — since intending to remember is not enough.
- Before the nozzle leaves the pump the first time you fuel a hired or new car, say "diesel" out loud. Silly, yes, yet it does the trick.
- Mistakes like this are straightforward to make while your mind is on something else, so the phone goes away.
- Some diesels come with a filler built to reject a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- The moment you realise, stop: less petrol in your tank makes a thinner mixture. What to do next doesn't change, though — still do not start the car.
Stone: already put petrol in a diesel?
The order of things is brief, then. Leave it unstarted, with the ignition off as well. The staff at the forecourt — whether at Morrisons itself or wherever you filled up — will usually help push it clear of the petrol pump if you ask. Ring 0333 366 0103 next, with three answers — the fuel, the approximate quantity, and whether it has run.
Corrosion and deposits are the issue with AdBlue, whereas petrol brings lost lubrication. So if it was AdBlue, say so — and see its own Stone page.
Stone petrol in a diesel tasks: why one costs more than another
A fair single price does not exist here: four situations, four separate jobs. Mostly, the cost moves with which one you are in. Beyond that it's the share — how much petrol got in against how much the tank holds — and then where your car is and whether a technician can reach it safely.
Three queries come first, before quoting, instead of after — what got in, how much, has it run — and this is the reason. Their answers are what turn a range into one firm number.
About Stone and where it is
Stone is a town in Staffordshire, situated on the River Trent at an elevation of 92 metres, with a mix of old and new buildings along its riverside. Stone lies approximately 8 miles south of Stoke-on-Trent and 129 miles northwest of London, near the villages of Walton and Oultoncross. Stone has a population of around 14787 people, predominantly living in detached houses. Stone benefits from its location in the West Midlands region, with good transport links to nearby cities.
Across Staffordshire and in Stone: fuel drain cover
Petrol in diesel call-outs around Stone — part of the ST postcode area — go to vans that also cover the spots around it, Walton, Stonefield and Oultoncross among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians work, and the car doesn't need to come to us.
Stone: still at the petrol pump?
Then, you couldn't be in a better place. Call, and keep it switched off.