Silvertonhill: Petrol in a Diesel Car? How Worried to Be
Provided it hasn't been started, you can worry less than you likely are. "Have I wrecked it?" is the first thing anyone around Silvertonhill asks, and the truthful answer is generally no, because petrol resting in a diesel tank hurts nothing until it is dragged through the system — by ignition priming, by your starter, or by driving. Keep it like that: leave the engine off and ring Petrol in Diesel. 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 a second time.
Petrol in a diesel: what does it do to your engine?
Passing through a motor, diesel is doing two jobs at once. Before it ignites, it protects — then it combusts. Your high-pressure pump and the injectors are built to very fine tolerances, and the diesel passing through them is what stops those surfaces from grinding against one another.
The second task petrol doesn't do at all, and the first it does badly. It's thinner than diesel and strips away the protection the fuel system hinges on, so a pump running on a petrol blend 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 knocking comes from.
The shape of the trouble is clear when you put those together. Not contact but circulation is what does the harm. Where the petrol is only in your tank, it's an issue of fuel, nothing more. Once the pump has been working on that petrol, a mechanical issue has started: anything shed by a pump that's grinding is carried onward to the fuel injectors with the fuel.
Four scenarios we see in Silvertonhill: how bad is petrol in a diesel?
Filled but never started — as good as it gets. At a forecourt, and truly only there, that petrol is still limited to the tank — since everywhere else the car was driven to reach it. The job is emptying and purging on the spot.
Ignition on, or started for a moment. Once primed, the system has drawn petrol out of your tank up to your filter and the fuel lines. Normally nothing more than emptying, cleaning and seeing to the filter, so still simple.
The pump has spent a couple of miles on weakened fuel — that is what driving the vehicle does. Distance is only half of it; how hard it was driven matters just as much. Either way this work includes that tank, the lines, your filter and fresh fuel through the entire system. On the school run to the local primary school, the distance is short. A run as far as Glasgow, under 15 miles away, is a very different job. So is any mileage on the M74, under a mile from Silvertonhill, where your engine has been working hard the whole time.
Driven on till it complained — knocking, smoke, an uneven idle, a soft throttle. That is your engine telling you its fuel no longer is behaving like diesel. Leave it where it stops: a lay-by, a side street, the verge on Larch Grove. The fuel drain and flush-through still come first, and they take care of it: if a car is pulled over soon, long-term damage is very rare.
Silvertonhill motorists and the petrol in a diesel stories they hear
Myth: topping up to full with diesel makes it fine. It does not. A fuller tank of the same mix is all it gives, since topping up takes out nothing. That advice presumes a diesel fuel system tolerates petrol by percentage. It doesn't.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. A current diesel sends its fuel through smaller components at higher pressure, which makes the lubrication count more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there is no harm done." Any petrol motor fed diesel usually will not run, and so the driver stops and the harm stops with them. Feed petrol to a diesel and it usually starts, idles and drives away as if nothing happened — all the while its pump is wearing. Being able to run isn't proof of being fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an old fix for a separate problem. None of what petrol thinned gets put back by it — and afterwards, the tank still holds that petrol.
Myth: "Drain the tank yourself and you're sorted." Once the motor has run, some of the petrol is no longer inside that tank: it is in your filter and your lines, and it goes straight back through your pump on the next start. Clearing petrol into a can at the roadside is also really dangerous.
Why petrol in a diesel takes place at all
No one does it on purpose, and it is seldom carelessness. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one mostly will not fit a petrol motor. That's how the forecourt makes it easy.
The moment habit stops matching your car is the moment it takes place. A car that's new to you — a hire car, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the drive. Your ordinary forecourt, its pumps now in a different order. Filling up in a hurry en route to Hamilton Central, with a train to catch. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. The 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 in Silvertonhill: preventing petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Check the pump's label; the colour is only a hint.
- In a motor you do not know, look inside the flap over the filler or at the cap before the first fill: plenty of motors state the fuel type there.
- Label your key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- Before the nozzle comes off the pump the first time you fill a hired or new car, say "diesel" out loud. Silly, perhaps, but it does the trick.
- Put the 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 add-on devices are available for the remainder. Count it as a backstop, then keep reading the petrol pump.
- Less petrol means a weaker blend, so stop the moment you realise — while remembering that your next step is unchanged. It's still not to crank it.
Already put petrol in a diesel in Silvertonhill?
The order of things is brief, then. Starting it is out, and so is switching on the ignition. The staff on the forecourt — whether at Esso itself or wherever you filled up — will usually help roll it clear of the petrol pump if you ask. Call 0333 366 0103 next, with three facts — the fuel, the approximate quantity, and whether it's run.
Say so if it was AdBlue rather than petrol: it's a different problem, with its own page for Silvertonhill, since AdBlue brings corrosion and deposits rather than lost protection.
One petrol in a diesel job in Silvertonhill costs more than another. Why?
There is no fair single price for this, because the four scenarios above are four separate tasks. The scenario itself does most of the work of moving your cost. The share matters next, meaning how much of that tank is petrol, followed by the location of the car and whether getting to it is safe for our van.
What got in, how much, and if it has run — three questions our technicians ask before pricing, not after, for exactly that reason. Those answers are what turn a range into one firm number.
About Silvertonhill
Silvertonhill is a suburban area situated on the riverside in South Lanarkshire, with a mix of residential properties including predominantly flat-style housing. Silvertonhill sits at an elevation of 72 metres, close to the nearby places of Barncluith, Low Waters, and Hamilton. Silvertonhill is located approximately 10 miles from Glasgow, making it a commuter-friendly location. Silvertonhill has a population of around 5428 residents, contributing to the wider urban area of Glasgow.
Across South Lanarkshire and in Silvertonhill: fuel drain cover
Silvertonhill waits in the ML postcode area, and the vans that answer petrol in diesel jobs there work the spots around it as well — Barncluith, Low Waters and Hamilton among them. No need to move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
In Silvertonhill and still at the petrol pump?
The best spot there is, then — that's where you are. Keep the vehicle switched off, and ring.