How Worried Should You Be? Petrol in a Diesel Car in Warboys
Far less than you probably are, provided it has not been started. Everyone in Warboys starts with "have I wrecked it?", and the fair answer is generally no: petrol left in the tank of a diesel stays harmless until priming, cranking or driving draws it into your fuel system. Petrol in Diesel is who to phone, with your engine kept off, and so it remains that way. Further down, this page sets out what petrol actually does inside a diesel, how far it might have gone, and how to stop it happening to you a second time.
Your engine and petrol in a diesel: what goes on
On its way through an engine, diesel has two tasks. It ignites, and before it burns it lubricates. Made to extremely fine gaps, your injectors and your pump depend on the diesel flowing through them to stop their surfaces wearing against one another.
Badly at the first, not at all at the second: that's petrol. It's thinner than diesel and removes the protection your fuel system hinges on, and so a pump running on a petrol mixture is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the clattering comes from.
Taken together, they make clear the shape the issue takes. The damage is done by movement, not by contact. A tank with petrol in it is a fuel problem. Once your pump has been working on that petrol, a mechanical fault has begun: anything shed by a pump that is wearing is carried downstream to your injectors with your fuel.
Four scenarios our technicians see in Warboys: how serious is petrol in a diesel?
The best case there is: filled up, never started. Just that tank has petrol in it, so the task is emptying your tank and cleaning the system where the car stands. This situation can only truly happen at a forecourt: anywhere else, the vehicle got there by being driven.
Ignition on, or started for a second. Petrol has come out of your tank and reached your filter and the fuel lines, since your system has been primed. That is usually still an easy job — a drain, a flush, and the fuel filter seen to.
Those few miles on the road meant the pump running on fuel thinned by petrol the whole way. Miles is only half of that; how hard it was driven matters equally. Either way this work runs to that tank, your lines, your filter and fresh fuel through the entire circuit. Short trips, like the school run to Warboys Primary Academy, are one thing. A run as far as Peterborough, under 15 miles away, is a very different job. So is any distance on the A1(M), under 10 miles from Warboys, where your engine has been labouring hard the whole time.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The fuel isn't behaving like diesel any more, and your motor is telling you. Leave it wherever it stops: a lay-by, a quiet street, the verge on Mill Green. A car pulled over quickly very seldom has long-term damage, since the drain and the flush, which still go first, take care of it.
Petrol in a diesel stories Warboys people hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. Percentage is not how a diesel fuel system tolerates petrol, however much that advice assumes.
"Modern diesels can handle a little petrol" — a myth, and nearer the reverse. At higher pressure, through finer parts: that's how a newer diesel handles its fuel, so the lubrication counts for more, not less.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. The motorist of a petrol engine fed diesel usually has no choice but to stop, because it will not run, and the harm stops there. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile the pump wears. Fine and running are not the same thing.
An outdated fix for a distinct issue lies behind this one. Myth: "Add some two-stroke oil and drive the car home." What petrol has diluted remains thinned, and that petrol stays inside the tank anyway.
Myth: "Drain your tank yourself and you are sorted." Once the engine has been run, some of that petrol is no longer in your tank: it is in the fuel filter and the fuel lines, and it goes right back through your pump at the next start. It's also genuinely dangerous to drain petrol into a can at the kerbside.
Why petrol in a diesel occurs so easily
Nobody does it on purpose, and it is seldom carelessness. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol motor. That is how the forecourt makes it easy.
It occurs when habit and the car stop matching. Hire cars, courtesy cars, and cars that are new to you. One petrol and one diesel on the driveway of the same household. A well-known forecourt with the pumps in a different order. Rushing for a train at Huntingdon and fuelling up en route. Years of petrol motors behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that is when. Add a back seat full of kids, a phone call or rain, and habit wins.
How to avoid petrol in a diesel at your next fill-up around Warboys
- The label is what counts, so read the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, yet not on every forecourt.
- In a motor you do not know, look inside the flap over your filler or at the cap before the first fill: many vehicles state the fuel type there.
- One of each in the household? Label the key to the diesel — a bright fob, a sticker — because meaning to remember is not enough.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car needs its first tank. It sounds daft. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away then keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop reading the pump.
- Stop the moment you notice. Less petrol inside that tank makes a weaker mixture. It does not change what to do next, which is still not to start the vehicle.
Petrol already in a diesel in Warboys? Begin here
In that case, there is only a short order of things. Do not turn the ignition on, and do not crank it. Still on the forecourt, at Ouse Valley Autos or anywhere else? Ask the staff to help you push the vehicle away from the petrol pump. Then ring 0333 366 0103 and tell us what got in, roughly how much, and if it's run.
Corrosion and deposits are the problem with AdBlue, whereas petrol brings lost lubrication. So if it was AdBlue, say so — and read its own Warboys page.
What makes one Warboys petrol in a diesel task cost more than the next
There is no honest single price for this, because the four situations above are four different tasks. Which of them you are in is mostly what moves your cost. Where the vehicle is matters too, and whether our van can safely reach it, after the proportion of petrol to what that tank holds.
Ahead of any quote, not after, come three queries: the fuel that went in, the volume, and whether it has run. That's why. A range turns into a straight figure when those replies are in.
About Warboys and where it is
Warboys is a village in Cambridgeshire, situated in the eastern part of England, with a population of around 2102 people. Warboys sits inland, approximately 31 metres above sea level, and is located near the villages of Mill End, Ramsey End, and Little End. Warboys is characterized by its predominantly detached housing stock and is within commuting distance of Peterborough, which is about 13.6 miles away. Warboys is also about 62 miles north of London.
Fuel drain cover in Warboys and across Cambridgeshire
Warboys rests in the PE postcode area, and the vans that answer petrol in diesel call-outs there work the locations near it as well — Mill End, Ramsey End and Little End among them. Our engineers drain where the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
At the pump in Warboys, right now?
No position is better: that is where you are. Leave the vehicle switched off, then ring.