Spitalhatch: Petrol in a Diesel Car? How Worried to Be
Less than you likely are, provided it hasn't been started. Till your ignition primes the pump, the starter cranks, or the vehicle is driven, petrol in a diesel tank just rests there and does no harm. Which makes the honest reply to the first Spitalhatch query — "have I wrecked it?" — normally no. Leave your engine off then phone Petrol in Diesel — that is how you keep it that way. The rest of this page sets out what petrol really does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
Inside your engine: what petrol in a diesel does
Passing through an engine, diesel does two things at the same time. Oiling comes before burning; it does both. What keeps the surfaces inside the high-pressure pump and the fuel injectors from wearing down against each other is the diesel passing through them — they're made to extremely fine clearances.
The second task 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 the mixture wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the knocking.
Together, those make the shape of the issue clear. The harm is done by circulation, not by contact. Where that petrol is only in that tank, it is a fault of fuel, nothing more. After the pump has been working on that petrol, a mechanical issue has begun: anything shed by a pump that's grinding is carried downstream to the fuel injectors with your fuel.
Petrol in a diesel around Spitalhatch: how serious is it? Four cases
Fuelled but never started — as good as it gets. That petrol is inside that tank and only your tank, and the task is a drain and a flush where your car sits. This is the one scenario that can only really take place at a forecourt, since anywhere else the vehicle has been driven to get there.
Ignition on, or started for a moment. Once primed, your system has drawn petrol from the tank up to the filter and the fuel lines. Normally little more than clearing, flushing and seeing to the fuel filter, and so still easy.
Those few miles on the road meant the pump working on fuel diluted by petrol the whole way. Mileage is only half of that; how hard it was driven matters just as much. Either way the work includes that tank, the fuel lines, the fuel filter and fresh fuel through the entire system. Short trips, such as the school run to Alton Infant School, are one thing. Very different a second time: a trip to Winchester, under 25 miles away, or any distance on the M3, under 10 miles from Spitalhatch, where the engine kept labouring hard.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. The motor is telling you the fuel is no longer acting like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Spitalhatch. The drain and flush still come first, and they take care of it: when a car is stopped early, permanent damage is very unusual.
What Spitalhatch people get told about petrol in a diesel — and the stories in it
Myth: topping up to full with diesel makes it fine. It doesn't. Topping up removes nothing; it gives you a fuller tank of the same mixture. Percentage isn't how a diesel fuel system copes with petrol, however much that guidance presumes.
"Modern diesels can handle a little petrol" — a myth, and closer to the opposite. At higher pressure, through more precise components: that is how a current diesel moves its fuel, and so the lubrication matters more, not less.
The myth that catches motorists out: if it starts and drives, it must be unharmed. The motorist of a petrol engine fed diesel usually stops, since it will not run, and the harm stops there. While the pump wears, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Running is not the same as fine.
An old workaround for a different fault is behind this one. Myth: "Add some two-stroke oil and drive it home." It does not put back what petrol has thinned, and that petrol is still inside the tank after that.
The next start draws petrol back round the pump from the fuel lines and the filter, where some of that ends up once your engine has run. That is why draining the tank yourself does not sort it — a myth. Also, a can of petrol filled at the kerbside is genuinely risky.
How does petrol in a diesel take place?
A careless moment is rarely the cause, and no one means to do it. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one generally won't fit a petrol car. That is how the forecourt makes it easy.
It happens when routine and your car stop matching. Courtesy car, hire car, or a motor that's brand new. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. A hurried fill en route to Alton with a train to catch. Precisely the moment it occurs: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. Add rain, a phone call or a back seat full of kids, and the hand repeats what it has always done.
How to prevent petrol in a diesel at your next fill-up around Spitalhatch
- Green for unleaded and black for diesel is usual in the UK — but not on every forecourt. Trust the label on the petrol pump, not the colour.
- In a motor you do not know, look inside the flap over the filler or at the cap before the first fill: plenty of motors print the fuel there.
- Good intentions count for less than a sticker or a fob in a bright colour on your diesel's key when a home has one of each. So mark it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It seems silly and it does the trick.
- Tuck the phone away. This is an easy mistake to make while you're thinking about something else.
- Add-on devices are available for cars without one, and some diesels come with a filler that will not take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Noticing it mid-fill? Stop there and then. A weaker mixture follows from less petrol inside your tank, yet the next stage stays the same: do not crank it.
Spitalhatch: already put petrol in a diesel?
The order of things is brief, then. Starting it is out, and so is turning on the ignition. The staff at the forecourt — whether at the nearest petrol station itself or wherever you filled up — will normally help roll it away from the pump if you ask. Phone 0333 366 0103 next, with three answers — your fuel, the rough quantity, and whether it's run.
Corrosion and deposits form the problem with AdBlue, where petrol brings lost protection. So if it was AdBlue, say so — and see its own Spitalhatch page.
One petrol in a diesel task around Spitalhatch costs more than another. Why?
A fair single quote does not exist here: four scenarios, four separate tasks. The scenario itself does most of the work of moving the cost. Two things come after that: the petrol that was put in as a proportion of what your tank takes, then the place the vehicle is in and whether a technician can get to it safely.
Three queries come first, before any quote, rather than after — what got in, how much, has it run — and this is the reason. Their answers are what change a range into one firm number.
About Spitalhatch itself
Spitalhatch is a suburban area situated on the riverside in Hampshire, with a relatively low elevation of 106 metres. Spitalhatch lies within the South East region of England, approximately 43.7 miles from London and 16.2 miles from the nearest city, Winchester. Spitalhatch is characterised by its predominant flat housing and a population of around 4242 residents.
Fuel drain cover in Spitalhatch and across Hampshire
Spitalhatch rests in the GU postcode area, and our vans that answer petrol in diesel calls there work the locations around it as well — Wilsom, Anstey and Alton among them. The vehicle doesn't need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the pump in Spitalhatch?
Then you are in the best place there is. Turned off it stays; then phone.