How Worried Should You Be? Petrol in a Diesel Car in Potton
Not started? Then less worried than you probably are. "Have I wrecked it?" is the first thing anyone around Potton asks, and the truthful answer is normally no, because petrol left in a diesel tank hurts nothing till it's drawn through your fuel system — by ignition priming, by the starter, or by driving. Leave your motor off and ring Petrol in Diesel — that keeps it that way. What petrol really does to a diesel, how to gauge how far it has gone, and how to keep it from happening again: that's the rest of this page.
The engine and petrol in a diesel: what goes on
Two tasks fall to diesel on its route through a motor. It burns, and before it ignites it lubricates. What keeps the surfaces inside the high-pressure fuel pump and the fuel injectors from wearing against one another is the diesel passing through them — they are built to very fine clearances.
The second job petrol does not do at all, and the first it does poorly. It is runnier than diesel and removes the lubrication your fuel system hinges 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's where the clattering comes from.
Combined, those leave the shape of the issue plain. It's circulation that causes the harm, not contact. Any tank with petrol in it is a fuel fault. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Four situations our technicians see in Potton: how serious is petrol in a diesel?
Fuelled but not once started — the best it gets. That petrol is inside your tank and only that tank, and the job is a drain and a flush where your car sits. This is the one scenario that can only really take place at a forecourt, because anywhere else the car has been driven to get there.
The ignition turned on, or a short start. Petrol has left your tank and got to the fuel filter and your lines, since the fuel system has been primed. Still generally easy: drain, flush, and your filter sorted.
Those few miles on the road meant the pump working on fuel weakened by petrol the whole way. The work is the tank, your lines, the filter and fresh fuel through the whole system, and how hard the vehicle was driven matters as much as how far. On the school run to Potton Primary School, the miles is small. A run as far as Cambridge, under 25 miles away, is a very different task. So is any miles on the A1(M), under 10 miles from Potton, where your engine has been running hard throughout.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The fuel isn't acting like diesel any more, and your engine is telling you. Leave it wherever it has stopped: a lay-by, a side street, the verge on Market Square. The fuel drain and flush-through still go first, and they deal with it: when a car is stopped early, lasting damage is very uncommon.
Potton drivers and that petrol in a diesel stories they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing comes out when you top up — your tank simply carries more of the same mixture. Percentage isn't how a diesel fuel system tolerates petrol, however much that advice assumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. Protection matters more on newer diesels, not less, since their fuel passes through smaller components at higher pressure.
"It starts, it drives, and so there is no harm" — the myth that trips up more drivers than any other. Feed diesel to a petrol engine and it normally won't run, so the driver stops — and the damage stops with them. Whilst your pump grinds, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. Running doesn't mean fine.
Not so: a two-stroke additive lets you to drive home. It was an old fix, supposed for another issue. It doesn't put back what petrol has diluted, and that petrol is still in your tank after that.
If the motor has been run, part of that petrol sits in the filter and your lines, not the tank — and the next start pulls it straight back through your pump. So the myth "drain that tank yourself and you are sorted" does not hold. Besides, petrol emptied into a can by the road is genuinely hazardous.
Why petrol in a diesel takes place at all
It's rarely carelessness, and no one does it on purpose. A diesel nozzle mostly won't 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 error straightforward, and just in one direction.
When habit and the vehicle stop matching, it happens. A new motor, a hire car or a courtesy car. Two vehicles on one drive, one petrol, one diesel. A forecourt you know, but with its pumps laid out differently. Filling up in a rush en route to Sandy, with a train to catch. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. Throw in rain, a phone call or a back seat full of children, and the hand does what it has always done.
How to avoid petrol in a diesel on your next fill-up in Potton
- The label is what matters, so read the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- Check the filler flap. Many vehicles state the fuel type inside the flap or on the cap. Look at it on the first fill in any vehicle you don't know.
- Mark your key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump. It seems daft and it does the trick.
- Whilst you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add are available for cars without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Stop the moment you realise. Less petrol in the tank makes a weaker mix. It doesn't change what to do next, which is still not to fire it up.
Already put petrol in a diesel in Potton?
The order of things is short, then. Leave it unstarted, with the ignition off too. Yet at the forecourt, at BP or anywhere else? Ask the attendants to help you roll it clear of the petrol pump. What was put in, roughly how much, and if it's run: tell us those when you call 0333 366 0103.
Corrosion and deposits form the issue with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and see its own Potton page.
One petrol in a diesel task around Potton costs more than another. Why?
There's no honest single quote for this, because the four scenarios above are four separate tasks. What moves your cost is chiefly which of them you're in. Beyond that it is the proportion — how much petrol was put in against how much the tank holds — and after that where the car is and whether a technician can reach it safely.
What was put in, how much, and whether it's run — three questions our engineers ask before quoting, not after, for precisely that reason. Given those answers, you get a straight figure instead of a range.
About Potton
Potton is a small town in Bedfordshire, situated on the banks of the River Great Ouse at an elevation of around 39 metres. Potton lies approximately 43 miles north of London and 15 miles west of Cambridge, with nearby villages including Snow Hill, Sutton, and Gamlingay Great Heath. Potton has a population of around 5728 people, predominantly living in semi-detached housing. Potton remains a residential community with a mix of old and new buildings.
Fuel drain cover around Potton and across Bedfordshire
Our vans answering petrol in diesel jobs in Potton, in the SG postcode area, also work the places near it, Snow Hill, Sutton and Gamlingay Great Heath among them. Our technicians drain wherever your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
At the pump around Potton, still?
Then you're in the best spot there is. Keep it off. Ring.