Petrol in a Diesel Car in Old Town: How Worried Should You Be?
Provided it hasn't been started, worry far less than you likely are. "Have I wrecked it?" is the first thing anyone in Old Town asks, and the honest answer is normally no, because petrol resting in a diesel tank harms nothing till it is drawn through the fuel system — by ignition priming, by the starter, or by driving. Petrol in Diesel is who to call, with the motor left off, and so it remains that way. Below, this page sets out what petrol actually does inside a diesel, how far it may have gone, and how to stop it happening to you a second time.
Your engine and petrol in a diesel: what goes on
Two tasks fall to diesel on its journey round a motor. It combusts, and before it combusts it protects. Built to extremely fine clearances, the injectors and the pump depend on the diesel flowing through them to keep their surfaces from wearing against one another.
Of these two tasks, petrol handles the first poorly and the second not at all. It is thinner than diesel and strips away the lubrication the fuel system depends on, 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 opposite of what a diesel needs from its fuel. That is where the clattering comes from.
Put these together and the shape of the trouble is clear. Contact doesn't do the harm — circulation does. Petrol in the tank is a fuel problem. The beginning of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to your injectors beyond it.
Four scenarios our technicians see around Old Town: how bad is petrol in a diesel?
The best case there can be: filled up, not once started. Being on a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With that petrol held in your tank alone, it's drained and cleaned on the spot, and nothing more is needed.
Ignition on, or started for a moment. Your system has been primed, so petrol has left your tank and got to your filter and your lines. Usually little more than clearing, cleaning and sorting the filter, so still straightforward.
Some miles driven, and the pump has spent every one of them labouring on thinned fuel. How hard your car was driven counts as much as how far, and this work covers that tank, your lines, the fuel filter and clean fuel through the whole system. Short trips, like the school run to Summer Lane Primary, are one thing. Very different once more: a run to Wakefield, under 10 miles away, or any distance on the M1, under 3 miles from Old Town, where the motor kept labouring hard.
Driven until it protested. Rattling, an uneven idle, smoke, a throttle that has gone soft. That's the motor telling you its fuel no longer is acting like diesel. Whether it is the verge on Queen's Avenue, a lay-by or a side road, stop where you are then leave it. What goes first is still the drain and flush, and that takes care of it, with lasting damage very uncommon if a vehicle is stopped quickly.
What Old Town drivers get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A bigger tank of the same mix is all it gives, because topping up takes out nothing. The assumption behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Newer diesels can handle a little petrol" — a myth, and closer to the reverse. A newer diesel runs its fuel through more precise components at higher pressure, which makes the lubrication matter more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up more drivers than any other. Any petrol motor fed diesel usually will not run, and so the motorist stops and the damage stops with them. Feed petrol to a diesel and it normally fires up, idles and drives away as if nothing has happened — all while its pump wears. Fine and running are not the same at all.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different issue. It does not put back what petrol has diluted, and the petrol is still inside the tank afterwards.
Myth: "Drain your tank yourself and you're sorted." Once your engine has been run, some of the petrol is no longer in the tank: it's in the filter and your lines, and it goes straight back through the pump at your next start. Also, a can of petrol drained by the roadside is genuinely risky.
How petrol ends up: petrol in a diesel
It is rarely carelessness, and nobody does it on purpose. 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 motor at all. The forecourt makes it simple, and the slip runs one way.
Routine and the car falling out of step is when it happens. A new vehicle, a hire car or a courtesy car. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. A hurried fill on the way to Barnsley with a train to catch. Years of petrol motors behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that's when. The hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
Next time you fill up around Old Town: preventing petrol in a diesel
- The label is what matters, so read the pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- Many vehicles state the fuel inside the filler flap or on the cap, so check it on the first fill in any car you don't know.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key if a house has one of each. So mark it.
- It sounds daft and it does the trick: on your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump.
- While you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Some diesels come with a filler designed to refuse a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- The moment you notice, stop: less petrol inside the tank means a thinner mixture. What to do next does not change, though — still don't crank it.
Put petrol in a diesel in Old Town already?
Then the order of things is brief. Do not fire it up, and do not turn the ignition on. The attendants at the forecourt — whether at Gulf itself or wherever you filled up — will normally help roll it clear of the pump if you ask. What was put in, roughly how much, and whether it has run: tell us that when you ring 0333 366 0103.
If it was AdBlue rather than petrol, say so. That is a different problem — corrosion and deposits rather than lost protection — and it has its own page for Old Town.
Old Town petrol in a diesel tasks: why one costs more than another
A fair single quote does not exist here: four situations, four separate jobs. What moves the cost is mostly which of them you are in. Two things come after that: the petrol that was put in as a share of what your tank holds, then the spot your car is in and whether a van can get to it safely.
What was put in, how much, and whether it's run — three questions we ask before pricing, not after, for precisely that reason. Those answers turn a range into a straight figure.
About Old Town itself
Old Town is a suburban area in South Yorkshire, situated approximately 8.7 miles from Wakefield and 152.9 miles from London. Old Town has a population of around 8373 people and is characterised by predominantly terraced housing. Old Town sits at an elevation of 140 metres, inland within the county of South Yorkshire. Old Town is near other local places such as Wilthorpe, Gateway Plaza, and Gawber.
Old Town and South Yorkshire: where our fuel drain cover reaches
Petrol in diesel call-outs around Old Town — part of the S postcode area — go to vans that also cover the places round it, Wilthorpe, Gateway Plaza and Gawber included. No need to move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations where we work.
In Old Town and still at the pump?
Then you are in the best place there is. Leave the car turned off, and ring.