Should You Worry? Petrol in a Diesel Car in Millbank
If it has not been started, you can worry far less than you likely are. Everyone around Millbank begins with "have I ruined it?", and the fair answer is generally no: petrol left inside that tank of any diesel stays harmless until priming, cranking or driving pulls it into the fuel system. Petrol in Diesel is who to call, with the engine left off, and so it stays that way. The rest of this page sets out what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you a second time.
Your engine and petrol in a diesel: what happens
Passing through an engine, diesel is doing two jobs at the same time. It lubricates first, and only then does it burn. Designed to extremely fine clearances, your injectors and the pump rely on your diesel moving through them to keep their surfaces from wearing against one another.
Badly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips away the protection a fuel system needs, leaving a pump running on that mixture wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the knocking.
Put these together and the shape of the problem is plain. The harm is done by movement, not by contact. Where the petrol is only inside that tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds travels on, borne by the fuel, into your injectors further along, which is why a pump that has been working on that petrol is where a mechanical fault starts.
Petrol in a diesel around Millbank: how serious is it? Four situations
Fuelled up, never started. The best case there can be. Only your tank has petrol in it, and so the task is emptying your tank and cleaning your system where your car sits. This situation can only really happen at a forecourt: anywhere else, the car got there by being driven.
A moment's running, or just the ignition on. With your system primed, the lines and filter already hold petrol that came from that tank. Drain, flush, see to the fuel filter: still usually simple.
Those few miles on the road meant your pump running on fuel diluted by petrol throughout. The work is your tank, the fuel lines, your filter and fresh fuel through the entire circuit, and how hard the car was driven counts as much as how far. Short trips, like the school run to the local primary school, are one matter. Driving as far as Inverness, over 50 miles away, makes a very different task — as does any distance on the M90, over 50 miles from Millbank, with the motor labouring hard all the way.
Driven until it protested. Knocking, a ragged idle, smoke, a throttle that has gone soft. The fuel isn't acting like diesel any more, and the motor is saying so. Whether it's the verge on Burnett Place, a lay-by or a side road, stop there then leave it. The fuel drain and flush-through still come first, and they deal with it: if a car is pulled over quickly, long-term damage is very rare.
Petrol in a diesel myths Millbank people hear
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A bigger tank of the same mixture is all you get, because topping up removes nothing. The idea behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. Smaller parts and higher pressure are how a modern diesel runs its fuel, and that makes the protection matter more, not less.
"It starts, it drives, and so no harm done" — the myth that catches more motorists than any other. Feed diesel to a petrol engine and it usually won't run, and so the motorist stops — and the harm stops with them. While the pump wears, a diesel fed petrol usually starts, idles and drives away as though nothing has happened. A running engine doesn't mean fine.
An outdated workaround for a distinct problem is behind this one. Myth: "Add some two-stroke oil and drive the car home." The petrol is still inside the tank after that, and whatever it has diluted isn't put back.
The next start draws petrol back round the pump out of your lines and your filter, where some of that ends up after the motor has run. That's why a DIY tank drain does not leave you sorted — a myth. Draining petrol into a can by the kerbside is also truly hazardous.
Petrol in a diesel: how does it occur?
A careless moment is rarely the cause, and nobody means to do it. A diesel nozzle mostly won't go into a petrol vehicle, yet the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and just in that direction.
Routine and the vehicle falling out of step is when it occurs. Any motor that is new to you — a hire car, on loan as a courtesy car, or brand new. Two vehicles on one driveway, one petrol, one diesel. The pumps in a different order on a well-known forecourt. A hurried fill en route to Thurso with a train to catch. A new-to-you diesel Volkswagen Tiguan, its first fuelling, and a motorist accustomed to petrol: precisely when it occurs. Throw in a back seat full of kids, a phone call or rain, and the hand wins.
Next time you fill up in Millbank: preventing petrol in a diesel
- The label is what counts, so check the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, yet not on every forecourt.
- Many vehicles state the fuel inside the filler flap or on the cap, and so check there on your first fill in any car you don't know.
- One of each in the house? Mark the key to your diesel — a bright fob, a sticker — because meaning to remember is not enough.
- It seems daft and it works: on the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- 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 built to refuse a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop reading the petrol pump.
- Spotting it halfway? Stop there and then. A thinner mixture results from less petrol in the tank, but the next step remains the same: do not fire it up.
Put petrol in a diesel in Millbank already?
In that case, there's just a short order of things. Don't fire it up, and don't switch your ignition on. The attendants at the forecourt — whether at Gleaner itself or wherever you filled up — will usually help push it clear of the pump if you ask. Next, 0333 366 0103. We'll ask what got in, roughly how much, and if it has been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a different issue — Millbank has a page all for it.
One petrol in a diesel task in Millbank costs more than another. Why?
Four different jobs sit behind the four scenarios above — which is why there's no honest single quote. Chiefly, your cost moves with which situation you are in. Two things come after that: the petrol that was put in as a share of what that tank takes, then the place the car is in and whether a technician can get to it safely.
What got in, how much, and whether it has run — three queries we ask before quoting, not after, for exactly that reason. The answers change a range into a straight figure.
About Millbank itself
Millbank is a coastal suburban area in the Highland county of Scotland, situated at a low elevation of 17 metres. Millbank lies near several neighbouring communities, including Mountpleasant, Springpark, and Mountvernon. Millbank is characterized by its predominantly semi-detached housing stock, reflecting the typical residential development patterns of similar Scottish coastal towns.
Millbank and Highland: where our fuel drain cover runs
Millbank sits in the KW postcode area, and the teams that answer petrol in diesel calls there work the locations around it as well — Mountpleasant, Springpark and Mountvernon among them. You need not bring your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations we drain.
Millbank: still at the petrol pump?
In that case, you could not be in a better position. Turned off it stays; then ring.