Should You Worry? Petrol in a Diesel Car in Thurnby Lodge
Unstarted? Then less worried than you likely feel. Petrol resting in a diesel tank does nothing to the engine until something pulls it through the fuel system — your ignition priming your pump, the starter, or the drive itself. So the truthful answer to the first query anyone around Thurnby Lodge asks, "have I wrecked it?", is normally no. Petrol in Diesel is who to phone, with your engine kept off, so it stays that way. What petrol actually does to a diesel, how to judge how far it's gone, and how to keep it from happening a second time: that's the remainder of this page.
Inside your engine: what petrol in a diesel really does
Diesel has two jobs on its way through an engine. It protects first, and only then does it burn. Made to extremely fine tolerances, the fuel injectors and the pump depend on your diesel moving through them to stop their surfaces wearing against one another.
Petrol handles the first job badly and the second not at all. The clattering comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication the fuel system hinges on, and any pump working on that mix is wearing itself.
Seen together, they show what shape the issue takes. Not contact but movement is what does the damage. A tank with petrol in it is a fuel problem. Whatever a worn pump sheds travels on, carried by your fuel, into your injectors downstream, which is why a pump that has worked on that petrol is where a mechanical issue begins.
How bad is petrol in a diesel? Four scenarios our technicians see around Thurnby Lodge
The best case there can be: filled up, not once started. That petrol is inside your tank and only the tank, and the job is a drain and a flush where the car stands. This is the one situation that can only truly happen at a forecourt, because anywhere else the vehicle has been driven to get there.
A brief spell of running, or just the ignition on. With your system primed, your lines and filter already contain petrol that came from the tank. Usually little more than clearing, flushing and sorting your filter, and so still simple.
Those few miles on the road were the pump running on fuel thinned by petrol the whole way. Tank, lines, filter, then fresh fuel put through the entire circuit: that is the work, and the way the vehicle was driven matters as much as the mileage. Short trips, like the school run to Willowbrook Mead Primary Academy, are one matter. A run as far as Leicester, under 5 miles away, is a very different job. So is any mileage on the M1, under 10 miles from Thurnby Lodge, where your engine has been labouring hard throughout.
Driven until it protested. Rattling, a ragged idle, smoke, a throttle that has gone soft. The fuel isn't behaving like diesel any more, and the engine is telling you. Stop where you are — on the verge on Cross Keys Green, at the kerb, down a side road — and don't move it. A vehicle stopped quickly very rarely has permanent damage, because the fuel drain and the flush, which still go first, take care of it.
Petrol in a diesel myths Thurnby Lodge drivers hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. A bigger tank of the same mixture is all it gives, because topping up takes out nothing. Percentage isn't how a diesel fuel system tolerates petrol, however much that guidance supposes.
If anything, the opposite holds. Myth: "A newer diesel can cope with a bit of petrol." Smaller components and higher pressure are how a current diesel runs its fuel, and that makes the protection matter more, not less.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel normally stops, because it will not run, and the harm stops with them. Feed petrol to a diesel and it usually starts, idles and pulls away like nothing has happened — all while its pump wears. Running does not mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an old fix for a distinct fault. None of what petrol thinned gets put back by it — and afterwards, the tank still contains that petrol.
If the engine has been run, part of the petrol is in the fuel filter and the lines, not your tank — and your next start sends it straight back through your pump. So the myth "drain your tank yourself and you're sorted" doesn't stand up. It is also truly risky to drain petrol into a can at the roadside.
Why petrol in a diesel happens at all
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle mostly won't fit a petrol car, yet the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake straightforward, and only in that direction.
When habit and the vehicle stop matching, it happens. Courtesy car, hire car, or a car that's brand new. A household with one petrol and one diesel on the driveway. A forecourt you know, but with its pumps arranged differently. Fuelling up in a hurry en route to Leicester, with a train to catch. Exactly the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
How to prevent petrol in a diesel at your next fill-up in Thurnby Lodge
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Read the petrol 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: many vehicles state the fuel type there.
- One of each in the house? Label your key to your diesel — a bright fob, a sticker — since meaning to remember is not enough.
- It sounds silly and it works: on your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- While you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Some diesels come with a filler built to reject a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- As soon as you realise, stop: less petrol in the tank makes a weaker blend. What to do next does not change, though — still don't fire it up.
Petrol already in a diesel in Thurnby Lodge? Start here
Short and simple, then, is the order of things. Starting it is out, and so is turning on your ignition. The attendants at the forecourt — whether at Tesco 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 — your fuel, the rough volume, and if it's run.
If it was AdBlue and not petrol, say so. That's a different issue — corrosion and deposits rather than lost lubrication — and it has its own page for Thurnby Lodge.
One petrol in a diesel task around Thurnby Lodge costs more than another. Why?
Four different tasks sit behind the four scenarios above — which is why there's no honest single price. The situation itself does most of the work of moving the cost. Two things follow that: the petrol that got in as a share of what that tank takes, then the place the car is in and whether a technician can reach it safely.
What was put in, how much, and if it's run — three questions our technicians ask before pricing, not after, for precisely that reason. Given those answers, there is a straight figure rather than a range.
About Thurnby Lodge, for a moment
Thurnby Lodge is a suburban area located on the outskirts of Leicester, situated near the riverside and approximately 3.4 miles from the city centre. Thurnby Lodge sits at an elevation of around 101 metres, with semi-detached housing being the predominant type of accommodation in the area. Thurnby Lodge is close to nearby places such as Scraptoft, Thurnby, and Nether Hall, and is part of the larger Leicester urban area.
Fuel drain cover around Thurnby Lodge and across Leicestershire
The teams answering petrol in diesel calls around Thurnby Lodge, in the LE postcode area, equally work the locations near it, Scraptoft, Thurnby and Nether Hall among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places we drain, and your car does not need to move to us.
Thurnby Lodge: still at the petrol pump?
In that case, you could not be in a better spot. Switched off it stays; then ring.