Paganhill: Petrol in a Diesel Car? How Worried to Be
Far less than you probably are, provided it has not been started. Petrol resting in a diesel tank does nothing to your engine until something draws it through your fuel system — the ignition priming your pump, your starter, or driving itself. So the honest answer to the first question anyone around Paganhill asks, "have I ruined it?", is usually no. Keep it that way: leave the engine off then ring Petrol in Diesel. What petrol actually does to a diesel, how to gauge how far it's travelled, and how to keep it from happening again: that is the remainder of this page.
What petrol in a diesel does to your engine
Two jobs fall to diesel on its journey through a motor. Lubricating comes before burning; it does both. Designed to extremely fine tolerances, your injectors and the pump depend on your diesel moving through them to stop their surfaces wearing against one another.
Badly at the first, not at all at the second: that is petrol. A pump working on a petrol mix is wearing itself out, since petrol is thinner than diesel and strips out the protection your fuel system relies on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where any clattering comes.
The shape of the issue is clear once you put those together. It is circulation that causes the damage, not contact. Petrol in the tank is a fuel fault. The beginning of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with the fuel to the fuel injectors downstream.
How bad is petrol in a diesel? Four scenarios our engineers see in Paganhill
Filled but not once started — the best it gets. Just your tank has petrol in it, and so the job is emptying that tank and flushing your system where the car sits. This scenario can only really take place on a forecourt: anywhere else, your car got there by being driven.
Started for a moment, or just your ignition on. Once primed, the system has drawn petrol from your tank up to your filter and the lines. Drain, flush, see to the filter: still normally straightforward.
Those few miles driven meant your pump labouring on fuel weakened by petrol throughout. The work is the tank, the fuel lines, the filter and fresh fuel through the whole circuit, and how hard your car was driven counts as much as how far. Short trips, like the school run to Callowell Primary School, are one matter. Any mileage on the M5, under 5 miles from Paganhill, means the engine working hard throughout, and a run to Gloucester, under 10 miles away, makes a very different job too.
It protested, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone lumpy. That is your engine telling you its fuel no longer is behaving like diesel. Leave it wherever it stops: a lay-by, a side street, the verge on Byron Road. The drain and flush still come first, and they deal with it: if a car is stopped quickly, long-term damage is very unusual.
Petrol in a diesel stories Paganhill motorists hear
Myth: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you are left with a fuller tank, still the same mixture. The assumption behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: a newer diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through finer components: that's how a modern diesel moves its fuel, and so the protection matters more, not less.
"It starts, it drives, so no harm done" — the myth that catches more motorists than any other. Feed diesel to a petrol motor and it usually won't run, so the driver stops — and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile your pump wears. Fine and running aren't the same thing.
An outdated workaround for a different problem is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol thinned gets put back by it — and later, the tank still contains that petrol.
Myth: "Drain the tank yourself and you're sorted." After your engine has been run, some of that petrol is no longer in that tank: it is in your filter and your lines, and it goes right back through your pump at your next start. It is also genuinely dangerous to drain petrol into a can at the roadside.
Why petrol in a diesel occurs at all
Nobody does it on purpose, and it is seldom carelessness. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol vehicle at all. The forecourt makes it simple, and the slip runs one way.
It occurs when habit and the car stop matching. Hire cars, courtesy cars, and cars that are new to you. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. A hurried fill on the way to Stroud with a train to catch. A new-to-you diesel Skoda Octavia, its first fuelling, and a motorist accustomed to petrol: precisely when it takes place. Throw in a back seat full of kids, a phone call or rain, and the hand wins.
Avoiding petrol in a diesel next time you fill up in Paganhill
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on each forecourt. The label is what counts.
- Inspect the filler flap. Plenty of vehicles state the fuel type 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 household? Label your key to the diesel — a coloured fob, a sticker — since meaning to remember is not enough.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It seems daft and it does the trick.
- Whilst you're thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- Stop as soon as you notice. Less petrol inside the tank means a thinner mixture. It does not change what to do next, which is still not to crank it.
Petrol already in a diesel around Paganhill? Start here
In that case, there is only a short order of things. Don't crank it, and don't turn the ignition on. Still on the forecourt, at Tesco or anywhere else? Ask the attendants to help you push it away from the petrol pump. What got in, roughly how much, and if it has run: tell us that when you ring 0333 366 0103.
Corrosion and deposits are the issue with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and see its own Paganhill page.
One petrol in a diesel job around Paganhill costs more than another. Why?
There's no fair single quote for this, since the four scenarios above are four separate jobs. The situation itself does most of the work of moving your cost. Where the vehicle is counts too, and whether our van can safely get to it, after the ratio of petrol to what the tank holds.
What got in, how much, and if it has run — three questions we ask before quoting, not after, for exactly that reason. The replies change a range into a straight figure.
About Paganhill itself
Paganhill is a suburban area located on the outskirts of Gloucester, situated near the river at an elevation of 103 metres. Paganhill sits in close proximity to nearby places such as Park End, Puckshole, and Highfield, and is characterized by its predominantly semi-detached housing stock. Paganhill is a relatively small community, with a population of approximately 2988 residents, and is within easy reach of Gloucester city centre, being just 7.8 miles away.
Fuel drain cover across Gloucestershire, Paganhill included
Paganhill waits in the GL postcode area, and the vans that answer petrol in diesel jobs there work the locations around it as well — Park End, Puckshole and Highfield among them. A forecourt, a supermarket car park, a lay-by or your own drive are all places we work, and your vehicle does not need to come to us.
In Paganhill and still at the petrol pump?
Nothing beats it: that is where you now are. Keep the car switched off, then ring.