Should You Worry? Petrol in a Diesel Car in Croughton
If it hasn't been started, you can worry less than you likely are. Till the ignition primes your pump, your starter cranks, or the vehicle is driven, petrol in a diesel tank simply sits there and does no harm. Which means the truthful reply to the first Croughton question — "have I wrecked it?" — usually no. Keep it that way: leave your motor off then ring Petrol in Diesel. The remainder 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.
What petrol in a diesel does to the motor
Two tasks fall to diesel on its route round a motor. It burns, and before it burns it protects. Built to extremely fine tolerances, your injectors and your pump depend on your diesel flowing through them to keep their surfaces from wearing against one another.
Badly at the first, not at all at the second: that is petrol. The knocking comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the fuel system depends on, and any pump working on such a blend is wearing itself.
Combined, those leave the shape of the issue plain. The damage is done by circulation, not by contact. Any tank with petrol in it is a fuel issue. Once your pump has been labouring on that petrol, a mechanical issue has started: anything shed by a pump that is wearing travels onward to the injectors with your fuel.
How bad is petrol in a diesel? Four scenarios our technicians see around Croughton
Fuelled but never started — the best it gets. That petrol is inside that tank and just the tank, and the task is a drain and a flush where the vehicle stands. This is the one situation that can only really happen at a forecourt, because anywhere else the car has been driven to get there.
The ignition switched on, or a brief start. The system has been primed, so petrol has left the tank and got to the fuel filter and the fuel lines. That's normally still a simple job — a drain, a flush, and the fuel filter seen to.
Driven a few miles. Now your pump has spent those miles running on weakened fuel. Tank, lines, filter, then fresh fuel put through the whole system: that is the work, and the way the vehicle was driven counts as much as the distance. Short trips, such as the school run to Croughton All Saints CofE Primary School, are one matter. Getting as far as Oxford, under 25 miles away, makes a very different job — as does any miles on the M40, under 3 miles from Croughton, with the motor working hard all the way.
Driven on till it protested — rattling, smoke, an uneven idle, a soft throttle. What you are hearing is the engine reporting fuel that no longer acts like diesel. Stop wherever you are — the verge on High Street, a lay-by, a side street — then leave the vehicle there. A car pulled over early very rarely has long-term damage, as the fuel drain and the flush-through, which still come first, sort it out.
Stories Croughton people hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up takes out nothing; it gives you a fuller tank of the same mixture. That advice assumes a diesel fuel system tolerates petrol by percentage. It does not.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. More precise components and higher pressure are how a current diesel runs its fuel, and that makes the lubrication count more, not less.
"It starts, it drives, so no harm done" — the myth that catches more drivers than any other. A petrol engine fed diesel generally won't run, and so the motorist stops and the harm stops with them. A diesel fed petrol usually starts, ticks over and drives away as if nothing has happened, whilst your pump grinds. A running engine does not mean fine.
Myth: a two-stroke additive makes it safe to drive home. It was an old workaround, meant for another fault. It doesn't put back what petrol has weakened, and the petrol is still inside your tank afterwards.
Once the engine has been run, part of that petrol is in the filter and the fuel lines, not that tank — and your next start pulls it right back through your pump. So the myth "drain the tank yourself and you are sorted" does not hold. Also, a can of petrol filled at the roadside is truly risky.
How does petrol in a diesel happen?
No one does it on purpose, and it's seldom carelessness. A diesel nozzle mostly will not go into a petrol motor, but the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake straightforward, and just in that direction.
When habit and the car stop matching, it occurs. A new motor, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. Your ordinary forecourt, its pumps suddenly in a different order. A hurried fill on the way to Kings Sutton with a train to catch. Years of petrol vehicles behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that is when. Throw in a back seat full of kids, a phone call or rain, and habit wins.
Next time you fill up in Croughton: avoiding petrol in a diesel
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Check the pump's label; the colour is only a clue.
- Inspect your filler flap. Many motors state the fuel inside the flap or on the cap. Look at it on your first fill in any car you do not know.
- One of each in the household? Mark your key to your diesel — a coloured fob, a sticker — since intending to remember is not enough.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car gets its first tank. It seems daft. It does the trick.
- While you are thinking about something else, this is an easy mistake to make — so put your phone away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to block a petrol nozzle, and add-on devices exist for cars without one. They are a safety net, not a reason to stop checking the pump.
- Less petrol means a weaker mixture, so stop the moment you notice — while remembering that your next step is unchanged. It's still not to fire it up.
Croughton: already put petrol in a diesel?
In that case, there is only a short order of things. Don't turn the ignition on, and do not crank it. Still on the forecourt, at A E Prentice or anywhere else? Ask the staff to help you roll the vehicle clear of the petrol pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it has been run.
If it was AdBlue and not petrol, say so. That's a different problem — corrosion and deposits and not lost lubrication — and it has its own page for Croughton.
Why one petrol in a diesel task around Croughton costs more than another
Four different jobs sit behind the four scenarios above — which is why there is no honest single price. What moves your cost is chiefly which of them you are in. Beyond that it is the ratio — how much petrol was put in against how much your tank takes — and then where the vehicle is and whether our van can get to it safely.
What got in, how much, and if it's run — three queries our technicians ask before costing, not after, for precisely that reason. Those answers are what change a range into one firm number.
About Croughton itself
Croughton is a small village in Northamptonshire, situated in the East Midlands region of England, with a population of around 671 people. Croughton sits at an elevation of 122 metres, approximately 57 miles northwest of London, and is close to the nearby cities of Oxford and the market towns of the surrounding area. Croughton is characterized by its predominantly detached housing stock, with the village being near to other small settlements such as New Buildings, Aynho, and Charlton.
Across Northamptonshire and around Croughton: fuel drain cover
Croughton waits in the NN postcode area, and our vans that answer petrol in diesel calls there work the spots near it as well — New Buildings, Aynho and Charlton among them. No need to bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
In Croughton and still at the petrol pump?
Then you're in the best position there is. Ring, and keep it turned off.