Should You Worry? Petrol in a Diesel Car in Prestolee
Unstarted? Then less worried than you likely are. Petrol sitting in a diesel tank does nothing to the engine till something pulls it through your fuel system — the ignition priming the pump, the starter, or driving on its own. So the honest answer to the first query everyone around Prestolee asks, "have I wrecked it?", is normally no. Petrol in Diesel is who to ring, with the engine kept off, and so it stays that way. The rest 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 doesn't happen to you again.
The engine and petrol in a diesel: what happens
Two jobs fall to diesel on its journey round a motor. Lubricating comes before burning; it does both. The high-pressure pump and the injectors are built to very fine tolerances, and your diesel passing through them is what stops those surfaces from wearing against each other.
Poorly at the first, not at all at the second: that is petrol. It is runnier than diesel and takes away the lubrication the system hinges on, and 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 reverse of what a diesel needs from its fuel. That is where the rattling comes from.
Put those together and the shape of the trouble is clear. Not contact but circulation is what does the damage. Where the petrol is only in the tank, it's a problem of fuel, nothing more. Whatever a worn pump sheds goes on, borne by the fuel, into your injectors further along, which is why a pump that has been working on the petrol is where a mechanical fault starts.
How bad is petrol in a diesel? Four situations our engineers see in Prestolee
The best case there can be: filled up, never started. The petrol is in the tank and only your tank, and the task is a drain and a flush where your car stands. This is the one scenario that can only really happen on a forecourt, because anywhere else your car has been driven to get there.
Ignition on, or started for a second. With your system primed, the fuel lines and filter already contain petrol that came from your tank. Normally little more than draining, rinsing and sorting your filter, and so still straightforward.
Driven a few miles. Now the pump has spent those miles running on thinned fuel. Tank, lines, filter, then clean fuel run through the whole system: that's the work, and the way the vehicle was driven counts as much as the distance. On the school run to Prestolee Primary School, the miles is small. Very different once more: a run to Salford, under 10 miles away, or some mileage on the Kearsley Spur, under a mile from Prestolee, where the engine never stopped running hard.
Driven on until it complained — clattering, smoke, a ragged idle, a soft throttle. The fuel isn't acting like diesel any more, and your motor is telling you. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Derby Road. A car stopped early very rarely has long-term damage, as the fuel drain and the flush, which still go first, deal with it.
Stories Prestolee 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. Nothing is removed when you top up — that tank just carries more of the same blend. Percentage isn't how a diesel fuel system tolerates petrol, however much that advice supposes.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. At higher pressure, through smaller components: that is how a current diesel handles its fuel, so the lubrication counts more, not less.
"It starts, it drives, and so there is no harm" — the myth that catches most drivers than any other. Diesel in a petrol motor usually leaves a motor that will not run: the driver stops, and so does the harm. Feed petrol to a diesel and it usually fires up, idles and drives away like nothing has happened — all while its pump wears. Running isn't the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old fix, meant for another fault. The petrol is still in the tank after that, and whatever it has thinned isn't put back.
The next start sends petrol back round your pump out of your lines and the filter, where some of that sits after the engine has been run. That is why draining your tank yourself does not sort it — a myth. It is also truly risky to drain petrol into a can at the kerbside.
Petrol in a diesel: how does it occur?
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle mostly will not go into a petrol vehicle, but the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake easy, and just in that direction.
It happens when routine and your car stop matching. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. A train to catch, and a rushed fill en route to Kearsley. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
Next time you fill up in Prestolee: preventing petrol in a diesel
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Check the petrol pump's label; the colour is just a clue.
- Many cars state the fuel inside your filler flap or on the cap, so check it on your first fill in a car you do not know.
- One of each in the household? Mark your key to your diesel — a bright fob, a sticker — because intending to remember isn't enough.
- "Diesel", out loud, before you lift the nozzle — every time a new or hired car gets its first tank. It sounds silly. It works.
- Mistakes like this are easy to make while your mind is on something else, and so the phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to block a petrol nozzle, and add-on devices exist for the remainder. Treat it as a safety net, and keep checking the pump.
- The moment you realise, stop: less petrol in that tank means a weaker blend. What to do next does not change, though — still do not crank it.
Put petrol in a diesel in Prestolee already?
Then the order of things is short. Starting it is out, and so is turning on your ignition. If you are still at the forecourt — Esso or anywhere else — ask the attendants to help you roll the car away from the pump. Ring 0333 366 0103 next, with three facts — your fuel, the rough volume, and if it has run.
Corrosion and deposits are the problem with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and see its own Prestolee page.
Why one petrol in a diesel job around Prestolee costs more than another
Four different jobs lie behind the four situations above — which is why there is no fair single price. Chiefly, the cost moves with which one you are in. Two things follow that: the petrol that got in as a proportion of what your tank takes, then the place the car is in and whether our van can reach it safely.
Three queries come first, before quoting, instead of after — what was put in, how much, has it run — and this is the reason. Given those answers, there is a straight figure rather than a range.
About Prestolee and where it is
Prestolee is a suburban area in Greater Manchester, situated on the riverside at an elevation of 53 metres, with semi-detached housing being the predominant type of accommodation. Prestolee lies approximately 5.7 miles from Salford and is close to nearby places such as Stoneclough, Nob End, and Kearsley. Prestolee has a population of around 2414 residents and is located in the North West region of England, about 169.7 miles from London.
Across Greater Manchester and in Prestolee: fuel drain cover
Prestolee waits in the M postcode area, and the vans that answer petrol in diesel call-outs there work the places around it as well — Stoneclough, Nob End and Kearsley among them. You need not move your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
At the pump around Prestolee, still?
In that case, you couldn't be in a better place. Keep it off. Call.