Should You Worry? Petrol in a Diesel Car in Cuddington
Not started? Then less anxious than you likely feel. Till the ignition primes the pump, your starter cranks, or the vehicle is driven, petrol in a diesel tank simply waits there and does nothing. Which means the truthful reply to that first Cuddington query — "have I ruined it?" — usually no. To leave the vehicle like that, ring Petrol in Diesel then leave the motor switched off. What petrol really does to a diesel, how to gauge how far it has gone, and how to stop it from happening again: that is the rest of this page.
Petrol in a diesel: what does it do to the engine?
Diesel has two tasks on its way through a motor. It protects first, and after that does it burn. Designed to very fine gaps, the injectors and the pump rely on your diesel moving through them to stop their surfaces wearing against one another.
Of these two jobs, petrol manages the first badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so a pump running on that mixture to wear itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the knocking.
Seen together, they make clear what shape the trouble has. Not contact but circulation is what causes the harm. A tank with petrol in it is a fuel issue. After the pump has been labouring on that petrol, a mechanical fault has begun: whatever is shed by a pump that's wearing travels onward to the injectors with the fuel.
Cuddington, petrol in a diesel: four cases, from mild to significant
Fuelled, and never started: nothing beats it. Only the tank has petrol in it, so the job is emptying the tank and purging the fuel system where the car stands. This situation can only really happen on a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a second. Once primed, the fuel system has drawn petrol from the tank up to the fuel filter and the fuel lines. That's usually still a simple task — a drain, a flush, and your filter dealt with.
Those few miles on the road were the pump working on fuel thinned by petrol the whole way. Tank, lines, filter, then fresh fuel run through the whole system: that is the work, and the way the car was driven counts as much as the mileage. Short trips, such as the school run to Sandiway Primary School, are one matter. Very different again: a run to Chester, under 15 miles away, or some mileage on the M56, under 10 miles from Cuddington, where the motor kept running hard.
Rattling, an uneven idle, smoke, a throttle gone soft: driven till it complained. That's the engine telling you its fuel no longer is acting like diesel. Leave it where it stops: a lay-by, a side street, the verge on Warrington Road. Permanent damage is very rare when a vehicle is pulled over soon, and the fuel drain and flush that still go first take care of it.
Cuddington motorists and that petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. The assumption behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
Not so: a newer diesel copes with a bit of petrol. Rather, the opposite. A modern diesel sends its fuel through smaller parts at higher pressure, which makes the protection matter more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that fools motorists. Feed diesel to a petrol motor and it generally won't run, so the driver stops — and the damage stops with them. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, while your pump grinds. Running is not the same as fine.
An outdated fix for a different issue is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has weakened remains thinned, and that petrol remains inside the tank regardless.
The next start draws petrol back round the pump from the fuel lines and your filter, where some of that ends up once the engine has run. That is why draining your tank yourself does not sort it — a myth. On top of that, petrol emptied into a can by the road is genuinely dangerous.
Petrol in a diesel: how does it occur?
No one does it on purpose, and it's seldom carelessness. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol vehicle at all. The forecourt makes it simple, and the mistake runs one way.
The moment routine stops matching the car is the moment it happens. Courtesy car, hire car, or a motor that's new. A household with one petrol and one diesel on the driveway. A forecourt you know, only with its pumps arranged differently. A rushed fill en route to the nearest station with a train to catch. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. With rain, a call coming in, or children to deal with, your hand simply does what it has always done.
Cuddington people: how to avoid petrol in a diesel next time
- Green for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Trust the label on the petrol pump, not the colour.
- Many vehicles state the fuel inside your filler flap or on the cap, so check it on your first fill in a motor you don't know.
- Label your key. In a home with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- Before the nozzle leaves the pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Daft, perhaps, but it works.
- Put your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to block a petrol nozzle, and add-on devices exist for the remainder. Count it as a safety net, then keep reading the petrol pump.
- Less petrol makes a thinner mix, so stop the moment you realise — while remembering that the next stage is unchanged. It's still not to crank it.
Already put petrol in a diesel in Cuddington?
The order of things is short, then. Leave it unstarted, with the ignition off as well. If you're still on the forecourt — Shell or anywhere else — ask the attendants to help you roll the vehicle clear of the pump. Then call 0333 366 0103 and tell us what got in, about how much, and whether it's run.
Corrosion and deposits form the trouble with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and see its own Cuddington page.
Cuddington petrol in a diesel jobs: why one costs more than another
There is no fair single price for this, because the four scenarios above are four separate jobs. The situation itself does most of the work of moving your cost. Where the vehicle is counts too, and whether our van can safely reach it, after the proportion of petrol to what your tank takes.
Before any quote, not after, we ask three queries: the fuel that went in, its quantity, and if it has run. That is why. A range becomes a straight figure when those answers are in.
About Cuddington itself
Cuddington is a village in Cheshire, situated on the banks of a river at an elevation of around 70 metres. Cuddington lies approximately 12.5 miles from Chester and is surrounded by nearby places such as Sandiway, Gorstage, and Stonyford. Cuddington has a population of around 833 people and is characterised by predominantly detached housing.
Fuel drain cover across Cheshire, Cuddington included
Cuddington sits in the CW postcode area, and our teams that answer petrol in diesel call-outs there work the spots near it as well — Sandiway, Gorstage and Stonyford among them. The car doesn't need to come to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
At the petrol pump around Cuddington, right now?
Then you are in the best spot there can be. Keep it off. Call.