Petrol in a Diesel Car in Burwell: How Worried Should You Be?
If it hasn't been started, you can worry less than you likely are. "Have I ruined it?" is the first question everyone around Burwell asks, and the truthful answer is generally no, since petrol left in a diesel tank harms nothing until it's dragged through your fuel system — by ignition priming, by the starter, or by being driven. To keep the car that way, phone Petrol in Diesel and leave your engine alone. Below, you will find what petrol actually does inside a diesel, how far it may have gone, and how to stop it happening to you a second time.
The engine and petrol in a diesel: what goes on
Two tasks fall to diesel on its journey round a motor. Before it combusts, it lubricates — then it combusts. The high-pressure pump and the injectors are built to very fine clearances, and the diesel passing through them is what stops those surfaces from grinding against each other.
Petrol handles the first job poorly and the second not at all. A pump running on a petrol mixture is wearing itself out, because petrol is runnier than diesel and strips out the protection your fuel system relies on. Petrol is also made to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that is where the rattling comes.
The shape of the problem is clear once you put those together. Not contact but movement is what causes the harm. All a tank with petrol in it amounts to is a fuel fault. After the pump has been labouring on that petrol, a mechanical fault has begun: whatever is shed by a pump that is wearing is carried downstream to the fuel injectors with your fuel.
Petrol in a diesel in Burwell: how bad is it? Four cases
Filled up, never started. The best case there is. At a forecourt, and genuinely only there, the petrol is still confined to the tank — because everywhere else the vehicle was driven to reach it. The task is draining and purging on the spot.
A brief spell of running, or merely the ignition on. With your system primed, the lines and filter already contain petrol that came from your tank. That's generally still an easy task — a drain, a flush, and your filter seen to.
Driven a couple of miles. Now the pump has spent these miles working on weakened fuel. Distance is only half of that; how hard it was driven matters just as much. Either way the work includes the tank, your lines, your filter and clean fuel through the entire circuit. Driving the children to Burwell Village College (Primary) is one sort of trip. Driving as far as Ely, under 10 miles away, makes a very different job — as does any mileage on the M11, under 15 miles from Burwell, with the motor running hard all the way.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone lumpy. What you are hearing is the motor signalling fuel that no longer acts like diesel. Leave it wherever it stops: a lay-by, a side street, the verge on The Causeway. What comes first is still the fuel drain and flush, and that takes care of it, with lasting damage very unusual when a car is pulled over soon.
Burwell motorists and the petrol in a diesel stories they hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A bigger tank of the same mix is all you get, since topping up takes out nothing. Percentage is not how a diesel fuel system copes with petrol, whatever that guidance assumes.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. Lubrication matters more on modern diesels, not less, since their fuel passes through more precise parts at higher pressure.
Myth: "If it starts and drives, there's no harm done." This is the one that fools motorists. The motorist of a petrol motor fed diesel usually stops, because it will not run, and the harm stops there. Feed petrol to a diesel and it normally fires up, idles and pulls away as if nothing happened — all while its pump wears. Running does not mean fine.
An old workaround for a separate fault is behind this one. Myth: "Add some two-stroke oil and drive it home." That petrol is still inside the tank after that, and what it has thinned is not put back.
Once the motor has run, part of the petrol sits in the fuel filter and your lines, not the tank — and the next start sends it right back through the pump. So the myth "drain that tank yourself and you're sorted" doesn't hold. It's also genuinely risky to drain petrol into a can at the kerbside.
How does petrol in a diesel happen?
No one does it on purpose, and it's seldom carelessness. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, while the diesel one mostly won't 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 new motor, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. Your usual forecourt, its pumps now in a different order. A train to catch, and a hurried fill on the way to Soham. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist used to petrol: precisely when it happens. Add rain, a phone call or a back seat full of kids, and the hand repeats what it has always done.
Next time you fill up around Burwell: avoiding petrol in a diesel
- The label is what counts, and so check the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, yet not on each forecourt.
- Plenty of cars state the fuel type inside your filler flap or on the cap, and so check there on your first fill in any vehicle you do not know.
- A coloured fob or a sticker on the diesel's key does more than any amount of intending to remember, for a home with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It seems daft and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away and keep your mind on the pump.
- Add-on devices are available for vehicles without one, and some diesels come with a filler that will not accept a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- Stop the moment you realise. Less petrol in your tank makes a weaker blend. It doesn't change what to do next, which is still not to fire it up.
Petrol already in a diesel around Burwell? Start here
In that case, there is only a short order of things. Starting it is out, and so is switching on the ignition. The staff on the forecourt — whether at Asda itself or wherever you filled up — will usually help roll it clear of the pump if you ask. Then ring 0333 366 0103 and tell us what got in, roughly how much, and if it has run.
Say so if it was AdBlue rather than petrol: it's a separate issue, with its own page for Burwell, since AdBlue brings corrosion and deposits instead of lost lubrication.
One petrol in a diesel job in Burwell costs more than another. Why?
The four situations above are four separate jobs, so no single price for this would be fair. What shifts your cost is chiefly which of them you are in. Two things follow that: the petrol that got in as a share of what the tank takes, then the place your car is in and whether a van can get to it safely.
What was put in, how much, and if it has run — three questions our engineers ask before quoting, not after, for precisely that reason. With those replies, there is a straight figure instead of a range.
About Burwell and its setting
Burwell is a village in Cambridgeshire, situated inland at an elevation of around 16 metres, approximately 9 miles from the city of Ely. Burwell lies within the Eastern region of England, about 56.5 miles from London, and is surrounded by nearby places such as Newnham and Reach. Burwell has a population of around 2458 people, predominantly living in detached housing. Burwell is a residential community with a mix of old and new properties.
Across Cambridgeshire and around Burwell: fuel drain cover
Petrol in diesel jobs in Burwell — part of the CB postcode area — go to vans that likewise cover the locations round it, Newnham, Old Pembroke Farm and Reach among them. You need not bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
Burwell: still at the pump?
The best position there is, then — that's where you are. Ring, and leave it turned off.