How Worried Should You Be? Petrol in a Diesel Car in Thorney Close
Far less than you probably are, if it hasn't been started. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through the fuel system — your ignition priming your pump, the starter, or the drive on its own. So the truthful answer to the first query everyone around Thorney Close asks, "have I wrecked it?", is usually no. Keep it like that: leave the engine off then call Petrol in Diesel. The rest of this page covers what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Petrol in a diesel: what does it do to the motor?
Diesel does two jobs on its way through an engine. It ignites, and before it combusts it lubricates. Made to very fine gaps, the injectors and the pump rely on the diesel moving through them to keep their surfaces from wearing against one another.
Badly at the first, not at all at the second: that's petrol. The knocking comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication your system hinges on, and any pump running on such a mix is wearing itself.
The shape of the problem is plain once you put those together. It's movement that causes the damage, not contact. Petrol in a tank is a fuel issue. Once your pump has been labouring on that petrol, a mechanical problem has started: anything shed by a pump that's wearing down is carried onward to the injectors with the fuel.
Four situations we see in Thorney Close: how bad is petrol in a diesel?
Filled but not once started — the best it gets. At a forecourt, and truly only there, that petrol is still limited to that tank — since anywhere else the car was driven to get to it. The task is draining and rinsing on the spot.
A moment's running, or merely your ignition on. Petrol has left your tank and got to the fuel filter and the lines, because the fuel system has been bled. Normally little more than draining, rinsing and sorting your filter, so still simple.
Those few miles driven were the pump running on fuel diluted by petrol throughout. How hard the vehicle was driven matters as much as how far, and the work takes in the tank, your lines, the fuel filter and fresh fuel through the whole circuit. A school run to Hasting Hill Academy is one matter. Any mileage on the Western Highway, under 5 miles from Thorney Close, means the motor has worked hard throughout, and a run to Sunderland, under 3 miles away, makes a very different task as well.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. What you are hearing is the motor reporting fuel that no longer runs like diesel. Pull up where you are — on the verge on Tay Road, at the kerb, down a side road — and do not move it again. Long-term damage is very rare if a vehicle is pulled over quickly, and the fuel drain and flush-through that still go first deal with it.
What Thorney Close motorists get told about petrol in a diesel — and the stories in it
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. A diesel fuel system does not accept petrol by percentage in the way that advice presumes.
Myth: a modern diesel copes with a bit of petrol. Rather, the reverse. Finer parts and higher pressure are how a current diesel runs its fuel, and that makes the lubrication matter more, not less.
This is the one that catches drivers. Myth: "If it starts and drives, there is no damage done." The driver of a petrol motor fed diesel normally has no choice but to stop, since it will not run, and the harm stops with them. A diesel fed petrol usually starts, idles and drives away as though nothing has happened, while your pump wears. Fine and running aren't the same at all.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different problem. The petrol is still in that tank afterwards, and whatever it has diluted is not put back.
If the motor has been run, part of the petrol sits in the filter and the lines, not your tank — and your next start pulls it straight back through the pump. So the myth "drain your tank yourself and you're sorted" does not hold. Also, a can of petrol drained at the roadside is genuinely hazardous.
How petrol ends up: petrol in a diesel
Nobody does it on purpose, and it's seldom carelessness. One way only, since of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one generally won't fit a petrol vehicle. That's how the forecourt makes it straightforward.
It happens when habit and your car stop matching. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. A rushed fill en route to Sunderland 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. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
Next time you fill up in Thorney Close: avoiding petrol in a diesel
- The label is what matters, and so read the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- Many motors state the fuel type inside your filler flap or on the cap, so check it on the first fill in a vehicle you don't know.
- Label the key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car gets its first tank. It seems silly. It does the trick.
- While you are thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Add-on devices are available for vehicles without one, and some diesels come with a filler that won't take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- Stop the moment you notice. Less petrol in your tank makes a thinner mixture. It does not change what to do next, which is still not to crank it.
Put petrol in a diesel in Thorney Close already?
Then the order of things is short. Starting it is out, and so is turning on the ignition. The staff at the forecourt — whether at BP itself or wherever you filled up — will usually help roll it clear of the petrol pump if you ask. What got in, about how much, and whether it has run: tell us that when you ring 0333 366 0103.
Say so if it was AdBlue rather than petrol: it's a different fault, with its own page for Thorney Close, because AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel task around Thorney Close costs more than another. Why?
There's no honest single price for this, because the four situations above are four different jobs. What moves the cost is mostly which of them you are in. Next it is the proportion — how much petrol went in against how much that tank takes — and after that where the car is and whether our van can get to it safely.
What got in, how much, and if it has run — three questions our engineers ask before costing, not after, for exactly that reason. With the answers, there is a straight figure rather than a range.
About Thorney Close
Thorney Close is a suburban area located on the outskirts of Sunderland, near the River Wear in Tyne and Wear. Thorney Close sits at an elevation of 84 metres, with views of the surrounding countryside and the nearby cities. Thorney Close is characterized by its semi-detached housing and is situated close to other residential areas, including Grindon and Hasting Hill. Thorney Close is approximately 2.5 miles from Sunderland city centre and 239.4 miles from London.
Thorney Close and Tyne and Wear: where our fuel drain cover reaches
Our teams answering petrol in diesel jobs around Thorney Close, in the SR postcode area, equally work the places around it, Grindon, Hasting Hill and Farringdon among them. Our technicians drain wherever your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Thorney Close: still at the petrol pump?
In that case, you couldn't be in a better place. Switched off it stays; then call.