How Worried Should You Be? Petrol in a Diesel Car in Pocket
Far less than you likely are, provided it has not been started. Petrol sitting in a diesel tank does nothing to your motor until something pulls it through your fuel system — the ignition priming your pump, the starter, or the drive itself. So the truthful answer to the first question anyone in Pocket asks, "have I wrecked it?", is usually no. Petrol in Diesel is who to phone, with your motor kept off, and so it remains that way. The remainder of this page covers what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you a second time.
Petrol in a diesel: what does it do to the motor?
Passing through an engine, diesel is doing two jobs at the same time. Lubricating comes before burning; it does both. The high-pressure pump and your injectors are built to very fine tolerances, and the diesel passing through them is what keeps those surfaces from wearing against one another.
Petrol handles the first job poorly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, leaving a pump on the blend wearing itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the rattling.
The shape of the issue is plain once you put those together. It's movement that does the damage, not contact. A 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's grinding is carried onward to the injectors with the fuel.
Petrol in a diesel around Pocket: how serious is it? Four cases
Fuelled but not once started — the best it gets. Being at a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol held in the tank alone, it's emptied and cleaned on the spot, and nothing more is needed.
Your ignition switched on, or a short start. Petrol has come out of that tank and got to your filter and your lines, since the system has been primed. Drain, flush, see to the filter: still normally straightforward.
Some miles driven, and your pump has spent every one of them working on diluted fuel. The work is that tank, the lines, the filter and fresh fuel through the entire system, and how hard the vehicle was driven counts as much as how far. On the school run to St Ethelbert's Roman Catholic Primary School, a Voluntary Academy, the distance is short. Getting as far as Salford, under 10 miles away, makes a very different task — as does any miles on the M61, under 3 miles from Pocket, with your engine running hard all the way.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone uneven. The fuel is not acting like diesel any more, and the motor is saying so. Whether it's the verge on Stanmore Drive, a lay-by or a side road, stop there and leave it. What goes first is still the fuel drain and flush, and that deals with it, with lasting damage very rare when a vehicle is pulled over early.
Stories Pocket motorists hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing comes out when you top up — your tank just carries more of the same mixture. A diesel fuel system doesn't accept petrol by percentage in the way that advice supposes.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. Lubrication counts more on modern diesels, not less, because their fuel runs through smaller parts at higher pressure.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it usually won't run, and so the driver stops — and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile your pump grinds. Running isn't the same as fine.
An outdated workaround for a different fault lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." It doesn't put back what petrol has diluted, and the petrol is still in your tank afterwards.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol lies in your filter and lines, ready to go straight back through your pump on the next start. Emptying petrol into a can at the kerbside is also truly dangerous.
How does petrol in a diesel happen?
A careless moment is seldom the cause, and no one means to do it. A diesel nozzle mostly will not go into a petrol vehicle, 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 that direction.
It occurs when habit and the vehicle stop matching. Hire cars, courtesy cars, and vehicles that are new to you. A household with one petrol and one diesel on the drive. A familiar forecourt with the pumps in a different order. A train to catch, and a rushed fill on the way to Bolton. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it happens. Add a back seat full of kids, a phone call or rain, and the hand wins.
Next time you fill up in Pocket: avoiding petrol in a diesel
- The label is what matters, and so check the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, yet not on each 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 there.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of meaning to remember, for a household with one of each.
- "Diesel", out loud, before you lift the nozzle — every time a new or hired car gets its first tank. It seems daft. It works.
- While you are thinking about something else, this is an easy mistake to make — so tuck your phone away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to reject a petrol nozzle, and add-on devices exist for motors without one. They are a safety net, not a reason to stop checking the petrol pump.
- Stop as soon as you notice. Less petrol inside your tank means a weaker mixture. It doesn't change what to do next, which is still not to fire it up.
Put petrol in a diesel around Pocket already?
The order of things is brief, then. Never fire it up, and don't turn your ignition on. Ask the attendants to help you roll it clear of the petrol pump if you are still on the forecourt, whether that's Esso or somewhere else. Next, 0333 366 0103. We will ask what went in, roughly how much, and if it has been run.
If it was AdBlue rather than petrol, say so. That is a separate problem — corrosion and deposits rather than lost protection — and it has its own page for Pocket.
What makes one Pocket petrol in a diesel job cost more than the next
Four different jobs lie behind the four situations above — which is why there's no honest single price. Which of them you're in is mostly what moves the cost. Next it's the share — how much petrol went in against how much that tank holds — and then where your car is and whether a technician can get to it safely.
What got in, how much, and if it's run — three questions our technicians ask before quoting, not after, for precisely that reason. Those answers are what change a range into one firm number.
About Pocket and where it is
Pocket is a suburban area in Greater Manchester, situated on the riverside at an elevation of 119 metres, with terraced housing being the predominant type of accommodation. Pocket is located near several other suburban areas, including Willows, Gilnow, and Deane, and is approximately 8.9 miles from the city of Salford. Pocket has a population of around 13075 residents and is part of the wider urban landscape of the North West region. Pocket is also relatively distant from London, being around 172.7 miles away.
Pocket and Greater Manchester: where our fuel drain cover reaches
Pocket sits in the BL postcode area, and the teams that answer petrol in diesel calls there work the locations near it as well — Willows, Gilnow and Deane among them. You need not bring the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
In Pocket and still at the pump?
Then you are in the best place there is. Leave the car turned off, and ring.