How Worried Should You Be? Petrol in a Diesel Car in Upper Morton
Provided it hasn't been started, you can worry less than you probably are. Until your ignition primes your pump, your starter cranks, or your car is driven, petrol in a diesel tank simply sits there and does nothing. Which means the honest reply to that first Upper Morton query — "have I ruined it?" — normally no. Leave your motor off then phone Petrol in Diesel — that is how you keep it that way. The rest of this page explains 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 again.
The engine and petrol in a diesel: what goes on
Diesel does two tasks on its way through an engine. It protects first, and only then does it burn. The high-pressure fuel pump and the fuel injectors are built to extremely fine tolerances, and your diesel passing through them is what stops those surfaces from wearing against each other.
The second job petrol doesn't do at all, and the first it does poorly. A pump running on a petrol mixture is wearing itself out, because petrol is thinner than diesel and strips out the protection your fuel system depends on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where any clattering comes.
Combined, those make the shape of the trouble plain. The damage is done by movement, not by contact. A tank with petrol in it is a fuel problem. Whatever a worn pump sheds travels on, borne by the fuel, into the fuel injectors downstream, which is why a pump that has been working on that petrol is where a mechanical fault starts.
Upper Morton, petrol in a diesel: four situations, from mild to significant
Filled up, and not started: no case is better. The petrol is in that tank and only the tank, and the job is a drain and a flush where the vehicle stands. This is the one situation that can only really occur on a forecourt, as anywhere else the car has been driven to get there.
Your ignition turned on, or a brief start. Once primed, your system has drawn petrol from your tank as far as the filter and the lines. Normally little more than draining, purging and sorting the filter, and so still easy.
Some miles driven, and the pump has spent every one of them running on thinned fuel. The work is the tank, the lines, the filter and fresh fuel through the whole circuit, and how hard the car was driven matters as much as how far. A school run to Manorbrook Primary School is one thing. Getting as far as Bristol, under 15 miles away, makes a very different job — as does any miles on the M5, under 3 miles from Upper Morton, with the motor labouring hard all the way.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven until it complained. That's your motor telling you its fuel has stopped behaving like diesel. Stop wherever you are — the verge on Gloucester Road, a lay-by, a side street — and leave the car where it is. Permanent damage is very unusual when a car is pulled over quickly, and the drain and flush-through that still go first sort it out.
What Upper Morton people get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A fuller tank of the same mix is all you get, since topping up takes out nothing. The assumption behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." At higher pressure, through more precise components: that's how a modern diesel handles its fuel, so the protection matters more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there is no harm done." Diesel in a petrol motor normally means a motor that will not run: the driver stops, and so does the damage. Feed petrol to a diesel and it usually starts, idles and pulls away as if nothing has happened — all while its pump wears. Being able to run is not the same as being fine.
An outdated workaround for a distinct fault is behind this one. Myth: "Add some two-stroke oil and drive the car home." None of what petrol thinned gets put back by it — and afterwards, the tank still holds the petrol.
The next start sends petrol back round the pump from your lines and the filter, where some of it sits once your engine has run. That is why a DIY tank drain doesn't sort it — a myth. On top of that, petrol drained into a can by the road is genuinely dangerous.
How petrol ends up: petrol in a diesel
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle mostly will not go into a petrol car, yet the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake easy, and only in that direction.
It occurs when routine and the car stop matching. A new vehicle, a hire car or a courtesy car. Households running one of each, petrol and diesel. Your normal forecourt, its pumps suddenly in a different order. Filling up in a rush on the way to Yate, with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is precisely the moment it happens. Your hand does what it has always done when you add rain, a phone call or a back seat full of kids.
Avoiding petrol in a diesel next time you fill up around Upper Morton
- The label is what matters, so check the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, yet not on every forecourt.
- Check your filler flap. Plenty of vehicles state the fuel inside the flap or on the cap. Look at it on the first fill in any vehicle you do not know.
- One of each in the home? Label your key to the diesel — a coloured fob, a sticker — since intending to remember isn't enough.
- Before the nozzle leaves the pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Silly, yes, yet it does the trick.
- Tuck your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to reject a petrol nozzle, and aftermarket devices are available for the rest. Count it as a backstop, and keep checking the petrol pump.
- Less petrol means a weaker mix, and so stop the moment you realise — though remembering that your next stage is unchanged. It is still not to fire it up.
Upper Morton: already put petrol in a diesel?
The order of things is brief, then. Do not fire it up, and do not switch your ignition on. If you are still at the forecourt — Thornbury Motors or anywhere else — ask the attendants to help you push the car clear of the pump. Next, 0333 366 0103. We will ask what got in, about how much, and if it's been run.
If it was AdBlue instead of petrol, say so. That is a separate problem — corrosion and deposits rather than lost lubrication — and it has its own page for Upper Morton.
One petrol in a diesel task around Upper Morton costs more than another. Why?
There is no fair single quote for this, because the four scenarios above are four different jobs. Mostly, the cost moves with which one you are in. The proportion matters next, meaning how much of the tank is petrol, followed by the position of the vehicle and whether getting to it is safe for our van.
Three queries come first, before any quote, instead of after — what went in, how much, has it run — and that is the reason. The answers turn a range into a straight figure.
About Upper Morton, for a moment
Upper Morton is a small hamlet in Gloucestershire, situated near the coast and close to the cities of Bristol and Gloucester. Upper Morton lies at an elevation of 38 metres, within a short distance of nearby settlements such as Morton and Lower Morton. Upper Morton is characterized by its predominantly detached housing stock, reflecting its rural setting. Upper Morton is also relatively close to major urban centres, with Bristol just 12 miles away and London around 103 miles distant.
Upper Morton and Gloucestershire: where our fuel drain cover runs
The vans answering petrol in diesel jobs in Upper Morton, in the BS postcode area, also work the spots near it, Morton, Lower Morton and Crossways among them. You need not move your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
In Upper Morton and still at the pump?
Nothing beats it: that is where you now are. Leave the car turned off, then ring.