Salterswall: Petrol in a Diesel Car? How Worried to Be
Less than you likely are, provided it hasn't been started. Till the ignition primes the pump, your starter turns, or the vehicle is driven, petrol in a diesel tank just rests there and does no harm. Which means the honest reply to that first Salterswall question — "have I wrecked it?" — usually no. Leave the engine off and phone Petrol in Diesel — that is how you keep it that way. What petrol really does to a diesel, how to judge how far it's gone, and how to stop it from happening again: that is the rest of this page.
What petrol in a diesel does to your engine
Passing through an engine, diesel is doing two things at once. It protects to begin with, and only then does it burn. Built to extremely fine gaps, the injectors and your pump rely on the diesel flowing through them to stop their surfaces wearing against one another.
Petrol handles the first task poorly and the second not at all. It's runnier than diesel and strips away the protection the fuel system rests on, so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the knocking comes from.
Taken together, they make clear the shape the trouble has. Contact doesn't do the damage — circulation does. Where the petrol is only inside your tank, it is a fault of fuel, nothing more. The beginning of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with your fuel to your injectors downstream.
Petrol in a diesel around Salterswall: how serious is it? Four cases
Fuelled but never started — as good as it gets. On a forecourt, and genuinely only there, that petrol is still confined to that tank — since everywhere else your car was driven to reach it. The task is draining and cleaning on the spot.
A moment's running, or merely your ignition on. The system has been bled, and so petrol has left the tank and reached the fuel filter and the fuel lines. Drain, flush, deal with the fuel filter: still usually easy.
Driven a couple of miles. Now the pump has spent those miles running on thinned fuel. Tank, lines, filter, then fresh fuel put through the whole system: that's the work, and the way the vehicle was driven matters as much as the miles. On the school run to The Oak View Academy, the mileage is small. Very different again: a run to Chester, under 15 miles away, or some distance on the M6, under 10 miles from Salterswall, where the motor never stopped labouring hard.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. What you are hearing is the engine signalling fuel that no longer runs like diesel. Pull up wherever you are — the verge on Chester Road, a lay-by, a side street — and leave the car where it is. The fuel drain and flush still come first, and they deal with it: when a car is stopped soon, long-term damage is very rare.
Salterswall people and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. A fuller tank of the same mixture is all you get, since topping up removes nothing. Percentage is not how a diesel fuel system tolerates petrol, however much that advice assumes.
Not so: a modern diesel copes with a bit of petrol. If anything, the reverse. Finer components and higher pressure are the way a modern diesel runs its fuel, and that makes the protection matter more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there is no damage done." The motorist of a petrol engine fed diesel usually stops, since it will not run, and the damage stops with them. Whilst the pump grinds, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. A running engine doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct fault. What petrol has diluted remains weakened, and the petrol stays in the tank regardless.
Once your engine has run, part of the petrol sits in the filter and the lines, not the tank — and your next start pulls it straight back through your pump. So the myth "drain the tank yourself and you're sorted" does not hold. It's also really hazardous to drain petrol into a can by the kerbside.
Why petrol in a diesel takes place at all
Carelessness is rarely the cause, and no one means to do it. A diesel nozzle mostly will not fit a petrol vehicle, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake straightforward, and only in one direction.
The moment habit stops matching the vehicle is the moment it takes place. Courtesy car, hire car, or a motor that's brand new. A household with one petrol and one diesel on the drive. A familiar forecourt with the pumps in a different order. A train to catch, and a rushed fill on the way to Winsford. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. Throw in a back seat full of kids, a phone call or rain, and the hand takes over.
Next time you fill up around Salterswall: preventing petrol in a diesel
- Check the pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on every forecourt. The label is what counts.
- Many cars state the fuel type inside the filler flap or on the cap, and so check there on your first fill in any car you don't know.
- One of each in the household? Mark your key to the diesel — a bright fob, a sticker — because meaning to remember is not enough.
- "Diesel", out loud, before you lift the nozzle — every time a new or hired car gets its first tank. It seems daft. It works.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away and keep your mind on the petrol pump.
- Some diesels have a filler designed to block a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the pump.
- The moment you realise, stop: less petrol in your tank makes a weaker mix. What to do next does not change, though — still don't fire it up.
Petrol already in a diesel in Salterswall? Begin here
Short and simple, then, is the order of things. Do not fire it up, and don't switch the ignition on. If you are still on the forecourt — Shell or anywhere else — ask the staff to help you roll it away from the pump. What was put in, about how much, and if it has run: tell us those when you phone 0333 366 0103.
If it was AdBlue instead of petrol, say so. That's a different issue — corrosion and deposits instead of lost lubrication — and it has its own page for Salterswall.
What makes one Salterswall petrol in a diesel job cost more than the next
The four scenarios above are four separate tasks, so no single price for this would be fair. Chiefly, the cost shifts with which situation you are in. The ratio counts next, meaning how much of your tank is petrol, followed by the position of the vehicle and whether reaching it is safe for our van.
Ahead of any quote, not after, come three queries: the fuel that was put in, its volume, and if it has run. That is why. The answers turn a range into a straight figure.
About Salterswall
Salterswall is a village in Cheshire, situated on the riverside at an elevation of 64 metres, with detached housing being the predominant type of accommodation. Salterswall lies near the villages of Littler, Marton, and Marton Green, and is approximately 13.8 miles from Chester. Salterswall is a relatively small community, with a population of around 840 people. Salterswall is located in the North West region of England, about 155.5 miles from London.
Across Cheshire and in Salterswall: fuel drain cover
Littler, Marton and Marton Green are among the spots near Salterswall that the same vans work, answering petrol in diesel jobs across Salterswall's CW postcode area. The car doesn't need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
At the petrol pump around Salterswall, right now?
Then, you could not be in a better spot. Switched off it remains; then call.