Should You Worry? Petrol in a Diesel Car in Heights
Likely less than you are now — provided no one has started it. Everyone around Heights starts with "have I ruined it?", and the fair answer is usually no: petrol left in that tank of any diesel stays harmless until priming, cranking or driving pulls it into the fuel system. Keep it like that: leave your engine off then ring Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel engine, the signs of how far it has spread, and ways to make sure you don't do it again.
What petrol in a diesel does to your engine
Passing through a motor, diesel is doing two things at once. Lubricating comes before burning; it does both. What keeps the surfaces inside the high-pressure pump and your injectors from wearing down against one another is the diesel flowing through them — they're designed to extremely fine tolerances.
Of those two jobs, petrol handles the first poorly and the second not at all. It's runnier than diesel and takes away the protection the fuel system rests on, so a pump running on a petrol mix is a pump wearing itself. And petrol is made 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 problem is plain. Not contact but circulation is what does the damage. Where the petrol is only inside the tank, it is an issue of fuel, nothing more. The beginning of a mechanical problem is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with your fuel to the fuel injectors downstream.
Four situations we see around Heights: how bad is petrol in a diesel?
The best case there is: filled up, not once started. Just the tank has petrol in it, so the task is clearing the tank and cleaning the system where the vehicle stands. This scenario can only really take place on a forecourt: anywhere else, your car got there by being driven.
Ignition on, or started for a second. Once primed, your system has pulled petrol from that tank as far as the filter and the lines. Drain, flush, deal with the filter: still usually simple.
Your pump now spent a few miles on weakened fuel — that's what driving the car does. Tank, lines, filter, then fresh fuel run through the whole circuit: that is the work, and the way the car was driven matters as much as the miles. Driving the children to Delph Primary School is one kind of trip. Any miles on the M62, under 5 miles from Heights, means the engine working hard throughout, and a run to Manchester, under 15 miles away, makes a very different job as well.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven until it complained. That is the engine telling you its fuel no longer is behaving like diesel. Stop on the spot — on the verge on SpringWood, at the kerb, down a side road — and do not move it. Long-term damage is very unusual when a vehicle is stopped early, and the drain and flush-through that still come first sort it out.
What Heights drivers get told about petrol in a diesel — and the stories in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." A bigger tank of the same mix is all you get, since topping up removes nothing. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance supposes.
Myth: a current diesel copes with a bit of petrol. Rather, the opposite. A newer diesel runs its fuel through finer parts at higher pressure, which makes the lubrication matter more, not less.
One myth that catches drivers out: if it starts and drives, it must be unharmed. A petrol motor fed diesel normally won't run, and so the motorist stops and the harm stops with them. While the pump wears, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. A running engine doesn't mean fine.
"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 weakened, and that petrol is still inside the tank after that.
Myth: "Drain that tank yourself and you're sorted." After the engine has been run, some of the petrol is no longer in that tank: it is in your filter and the fuel lines, and it goes straight back through your pump on your next start. On top of that, petrol emptied into a can by the road is truly risky.
How does petrol in a diesel take place?
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle generally will not fit a petrol car, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake straightforward, and just in that direction.
Routine and the vehicle falling out of step is when it happens. Any car that's new to you — a hire car, on loan as a courtesy car, or just bought. Two cars on one drive, one petrol, one diesel. A forecourt you know, but with its pumps laid out differently. Filling up in a rush on the way to Greenfield, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist used to petrol: exactly when it happens. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
Next time you fill up around Heights: avoiding petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Check the petrol pump's label; the colour is only a hint.
- The first fill in a strange motor is the time to check your filler flap — inside it, or on the cap, many cars state which fuel they take.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key if a household has one of each. So mark it.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car needs its first tank. It seems silly. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck the phone away then keep your mind on the pump.
- Some diesels come with a filler built to refuse a petrol nozzle, and devices you can add are available for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the pump.
- Stop as soon as you realise. Less petrol in the tank means a weaker mix. It doesn't change what to do next, which is still not to start it.
Petrol already in a diesel around Heights? Start here
Short and simple, then, is the order of things. Don't turn your ignition on, and do not start it. If you're still at the forecourt — Shell or anywhere else — ask the staff to help you push it clear of the petrol pump. Then phone 0333 366 0103 and tell us what went in, roughly how much, and if it's run.
Say so if it was AdBlue instead of petrol: it's a different problem, with its own page for Heights, because AdBlue brings corrosion and deposits rather than lost lubrication.
Why one petrol in a diesel job around Heights costs more than another
Four separate jobs lie behind the four scenarios above — which is why there is no fair single quote. The situation itself does most of the work of moving your cost. Where your car is counts too, and whether a technician can safely reach it, after the share of petrol to what your tank takes.
That is why we ask three queries before pricing instead of after: what went in, how much, and whether it has run. With the answers, you get a straight figure rather than a range.
About Heights and its setting
Heights is a locality in Greater Manchester, situated on the riverside at an elevation of 240 metres, with views of the surrounding countryside. Heights is located near several nearby places, including Delph Greave, Delph, and Grange, and is approximately 11.2 miles from Manchester. Heights has a population of around 845 people, predominantly living in terraced housing. Heights is also relatively distant from London, at around 163.5 miles away.
Heights and Greater Manchester: where our fuel drain cover runs
Heights rests in the OL postcode area, and our teams that answer petrol in diesel call-outs there work the locations around it as well — Delph Greave, Delph and Grange among them. Our technicians drain wherever the vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Still at the pump around Heights?
The best place there is, then — that's where you are. Call, and keep it turned off.