How Worried Should You Be? Petrol in a Diesel Car in Sudden
Far less than you likely are, if it hasn't been started. Petrol resting in a diesel tank does nothing to your engine till something pulls it through the fuel system — the ignition priming the pump, your starter, or the drive itself. So the truthful answer to the first query everyone in Sudden asks, "have I ruined it?", is usually no. Petrol in Diesel is who to call, with the engine left off, and so it stays that way. What petrol actually does to a diesel, how to judge how far it's travelled, and how to stop it from happening again: that is the rest of this page.
Inside the motor: what petrol in a diesel really does
On its way through an engine, diesel has two jobs. Before it combusts, it protects — then it ignites. Extremely fine gaps are built into the injectors and the high-pressure pump, and just the diesel flowing through keeps their surfaces from grinding together.
Petrol handles the first task badly and the second not at all. The rattling comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the lubrication the system depends on, and any pump working on such a blend is wearing itself.
Put these together and the shape of the problem is plain. Contact doesn't do the damage — movement does. Petrol in the tank is a fuel fault. Once your pump has been working on that petrol, a mechanical problem has started: whatever is shed by a pump that's wearing down travels onward to the injectors with your fuel.
Sudden, petrol in a diesel: four situations, from mild to major
Fuelled but never started — the best it gets. Only that tank has petrol in it, so the job is clearing your tank and flushing the fuel system where the car stands. This scenario can only truly take place at a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a second. Once primed, your system has drawn petrol out of the tank as far as the fuel filter and your lines. Still generally easy: drain, flush, and the fuel filter seen to.
A few miles driven, and the pump has spent each of them working on weakened fuel. Tank, lines, filter, then clean fuel put through the whole circuit: that is the work, and the way the vehicle was driven counts as much as the mileage. Driving the children to Brimrod Community Primary School is one kind of trip. Any mileage on the A627(M), under a mile from Sudden, means the motor working hard throughout, and a run to Manchester, under 10 miles away, makes a very different job as well.
Driven on until it complained — clattering, smoke, a lumpy idle, a soft throttle. That's your motor telling you its fuel no longer is acting like diesel. Whether it is the verge on Roch Valley Way, a lay-by or a side street, stop there then leave it. Long-term damage is very rare if a car is stopped soon, and the fuel drain and flush that still go first sort it out.
Myths Sudden drivers 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 removes nothing; it gives you a fuller tank of the same mix. The idea behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
Not so: a modern diesel copes with a bit of petrol. If anything, the opposite. Smaller parts and higher pressure are the way a current diesel runs its fuel, and that makes the lubrication count more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that catches drivers. The driver of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump wears. Running isn't the same as fine.
Myth: "Add some two-stroke oil and drive it home." It is an old workaround for a distinct problem. That petrol is still inside the tank after that, and what it has thinned isn't put back.
The next start draws petrol back round the pump from the lines and the filter, where some of it ends up after your engine has been run. That's why a DIY tank drain does not sort it — a myth. Emptying petrol into a can at the kerbside is also genuinely risky.
How it happens: petrol in a diesel
It is rarely carelessness, and no one does it on purpose. A diesel nozzle mostly will not go into a petrol motor, but the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake simple, and only in one direction.
The moment habit stops matching the car is the moment it happens. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. A train to catch, and a rushed fill en route to Castleton. The first fill-up in a diesel Volkswagen Tiguan after years of driving petrol is precisely the moment it takes place. The hand does what it has always done when you add rain, a phone call or a back seat full of kids.
Preventing petrol in a diesel next time you fill up around Sudden
- Read the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on every forecourt. The label is what counts.
- The first fill in an unfamiliar motor is the time to check your filler flap — inside it, or on the cap, plenty of vehicles state which fuel they take.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of meaning to remember, for a house with one of each.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car gets its first tank. It seems silly. It does the trick.
- Mistakes like this are easy to make while your mind is on something else, and so your phone goes away.
- Some diesels have a filler built to refuse a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Stop as soon as you notice. Less petrol in your tank means a weaker blend. It doesn't change what to do next, which is still not to crank it.
Put petrol in a diesel in Sudden already?
In that case, there's only a short order of things. Leave it unstarted, with the ignition off as well. The attendants on the forecourt — whether at Tesco itself or wherever you filled up — will normally help push it clear of the petrol pump if you ask. What got in, about how much, and whether it's run: tell us those when you call 0333 366 0103.
Corrosion and deposits are the trouble with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and read its own Sudden page.
One petrol in a diesel task around Sudden costs more than another. Why?
A fair single price does not exist here: four situations, four separate jobs. What moves the cost is mostly which of them you are in. Where the vehicle is counts too, and whether our van can safely reach it, after the ratio of petrol to what the tank takes.
That's why we ask three queries before pricing rather than after: what got in, how much, and whether it's run. Given those replies, you get a straight figure rather than a range.
About Sudden itself
Sudden is a suburban area in Greater Manchester, situated near the River Roch and close to the towns of Rochdale and Heywood. Sudden sits at an elevation of 127 metres, with semi-detached housing being the predominant type of accommodation in the area. Sudden is located near several other suburban areas, including Marland, Stoneyfield, and Kirkholt, and is around 9 miles from Manchester city centre.
Fuel drain cover across Greater Manchester, Sudden included
Sudden rests in the OL postcode area, and our vans that answer petrol in diesel call-outs there work the spots around it as well — Marland, Stoneyfield and Kirkholt among them. A forecourt, a supermarket car park, a lay-by or your own drive are all locations we drain, and your vehicle does not need to come to us.
Still at the pump around Sudden?
In that case, you could not be in a better position. Turned off it remains; then phone.