Should You Worry? Petrol in a Diesel Car in Holmcroft
Less than you probably are, if it has not been started. Till your ignition primes the pump, the starter turns, or your vehicle is driven, petrol in a diesel tank just sits there and does nothing. Which means the honest reply to the first Holmcroft question — "have I ruined it?" — normally no. To leave it that way, phone Petrol in Diesel then leave the motor switched off. The rest of this page covers 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.
The motor and petrol in a diesel: what goes on
Passing through a motor, diesel does two jobs at once. It combusts, and before it ignites it protects. Very fine tolerances are built into the fuel injectors and your high-pressure pump, and just your diesel running through keeps their surfaces from grinding together.
The second job petrol does not do at all, and the first it does poorly. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump on that mixture wearing itself. It is also made to resist igniting under compression — the opposite of what a diesel needs — which is why you hear the rattling.
Together, those make the shape of the problem plain. Not contact but movement is what causes the damage. All a tank with petrol in it amounts to is a fuel problem. Whatever a worn pump sheds goes on, carried by your fuel, into the fuel injectors downstream, which is why a pump that has worked on the petrol is where a mechanical issue starts.
How serious is petrol in a diesel? Four situations we see in Holmcroft
The best case there can be: filled up, not once started. On a forecourt, and really only there, that petrol is still limited to your tank — because everywhere else the vehicle was driven to reach it. The job is emptying and purging on the spot.
Started for a moment, or only your ignition on. Once primed, the system has pulled petrol out of your tank up to the filter and the fuel lines. That's usually still an easy task — a drain, a flush, and the fuel filter seen to.
Driven a few miles. Now the pump has spent these miles working on diluted fuel. Distance is only half of that; how hard it was driven matters just as much. Either way this work runs to the tank, your lines, your filter and clean fuel through the entire system. On the school run to Tillington Manor Primary School, the distance is small. Getting as far as Stoke-on-Trent, under 15 miles away, makes a very different job — as does any mileage on the M6, under a mile from Holmcroft, with the motor running hard all the way.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone ragged. What you are hearing is your motor signalling fuel that no longer runs like diesel. Whether it is the verge on Second Avenue, a lay-by or a side road, stop where you are and leave it. The fuel drain and flush-through still come first, and they take care of it: if a vehicle is pulled over early, permanent damage is very uncommon.
Stories Holmcroft motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It does not. A fuller tank of the same mixture is all you get, since topping up removes nothing. A diesel fuel system doesn't tolerate petrol by percentage in the way that advice supposes.
Myth: a current diesel copes with a bit of petrol. If anything, the reverse. More precise parts and higher pressure are how a newer diesel runs its fuel, and that makes the lubrication count more, not less.
One myth that catches drivers out: if it starts and drives, it must be unharmed. Any petrol motor fed diesel normally won't run, and so the motorist stops and the damage stops with them. Whilst the pump grinds, a diesel fed petrol usually starts, idles and drives away as though nothing has happened. A running engine does not mean fine.
An outdated fix for a distinct fault is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." That petrol is still inside the tank after that, and whatever it has diluted is not put back.
Myth: "Drain the tank yourself and you are sorted." Once the engine has been run, some of that petrol is no longer inside your tank: it is in the fuel filter and the lines, and it goes straight back through the pump on your next start. Besides, petrol emptied into a can by the road is truly hazardous.
How it happens: petrol in a diesel
It is seldom carelessness, and nobody does it on purpose. One way only, since of the nozzles: the smaller petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally will not fit a petrol motor. That is how the forecourt makes it straightforward.
It happens when habit and the vehicle stop matching. A motor that's new to you — hired, on loan as a courtesy car, or just bought. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. A rushed fill en route to Stafford with a train to catch. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
Preventing petrol in a diesel next time you fill up in Holmcroft
- The label is what counts, and so check the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- Many motors state the fuel inside the filler flap or on the cap, so check it on the first fill in any vehicle you do not know.
- One of each in the household? Label your key to your diesel — a bright fob, a sticker — because intending to remember is not enough.
- "Diesel", aloud, before you lift the nozzle — every time a new or hired car needs its first tank. It sounds daft. It does the trick.
- While you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- 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 backstop, not a reason to stop checking the pump.
- As soon as you realise, stop: less petrol inside your tank means a weaker mixture. What to do next does not change, though — still don't crank it.
Petrol already in a diesel around Holmcroft? Start here
Then the order of things is short. Leave it unstarted, with the ignition switched off too. If you are still at the forecourt — Shell or anywhere else — ask the staff to help you push it away from the petrol pump. Phone 0333 366 0103 next, with three facts — your fuel, the approximate amount, and whether it's run.
Say so if it was AdBlue rather than petrol: it is a separate problem, with its own page for Holmcroft, because AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel job in Holmcroft costs more than another. Why?
The four situations above are four different tasks, so no single quote for this would be honest. The situation itself does most of the work of moving your cost. Where the vehicle is counts too, and whether a technician can safely reach it, after the proportion of petrol to what that tank holds.
That's why our engineers ask three questions before pricing instead of after: what was put in, how much, and if it has run. Their answers are what change a range into one firm number.
About Holmcroft
Holmcroft is a suburban area in Staffordshire, situated near the River Trent at an elevation of 82 metres. Holmcroft lies within the West Midlands region, approximately 13.9 miles from Stoke-on-Trent and 124.3 miles from London. Holmcroft is characterised by its semi-detached housing and proximity to nearby places such as Tillington and Trinity Fields. Holmcroft has a population of around 5028 residents.
Fuel drain cover across Staffordshire, Holmcroft included
Petrol in diesel calls around Holmcroft — part of the ST postcode area — go to vans that also cover the places about it, Tillington, Trinity Fields and Parkside included. The vehicle does not need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the pump in Holmcroft?
In that case, you couldn't be in a better position. Switched off it stays; then ring.