How Worried Should You Be? Petrol in a Diesel Car in Calcot Row
Far less than you likely are, if it has not been started. Everyone in Calcot Row begins with "have I wrecked it?", and the fair answer is generally no: petrol resting inside the tank of a diesel stays harmless till priming, cranking or driving draws it into the system. Keep it that way: leave your motor off then phone Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and the way to make sure you never do it again.
Petrol in a diesel: what does it do to the motor?
Passing through a motor, diesel is doing two things at the same time. It combusts, and before it ignites it protects. Designed to extremely fine tolerances, your injectors and the pump rely on your diesel moving through them to stop their surfaces wearing against one another.
The second task petrol doesn't do at all, and the first it does badly. A pump working on a petrol mix is wearing itself out, since petrol is runnier than diesel and strips out the protection the fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where the rattling starts.
Together, those leave the shape of the issue clear. It is circulation that causes the damage, not contact. All a tank with petrol in it amounts to is a fuel issue. Whatever a worn pump sheds travels on, borne by your fuel, into the injectors further along, which is why a pump that has been working on that petrol is where a mechanical problem starts.
Four scenarios we see in Calcot Row: how serious is petrol in a diesel?
Filled up, never started. The best case there is. On a forecourt, and genuinely only there, the petrol is still confined to your tank — because anywhere else the car was driven to reach it. The job is draining and cleaning on the spot.
A brief spell of running, or merely the ignition on. Petrol has come out of the tank and got to your filter and the lines, since your system has been primed. Still generally straightforward: drain, flush, and your filter sorted.
Some miles driven, and your pump has spent each of them labouring on weakened fuel. Tank, lines, filter, then clean fuel run through the entire circuit: that's the work, and the way your car was driven counts as much as the mileage. A school run to Calcot Junior School is one matter. A run as far as Oxford, under 25 miles away, is a very different job. So is any miles on the M4, under a mile from Calcot Row, where the motor has been working hard the whole time.
It protested, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. The fuel isn't behaving like diesel any more, and your motor is saying so. Stop where you are — on the verge on Langley Hall Drive, at the kerb, down a side road — and do not move it again. What goes first is still the fuel drain and flush-through, and that sorts it out, with permanent damage very rare when a vehicle is stopped soon.
What Calcot Row drivers get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up removes nothing; it gives you a bigger tank of the same mix. The idea behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Not so: a newer diesel copes with a bit of petrol. Rather, the reverse. A current diesel sends its fuel through more precise components at higher pressure, which makes the protection count more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no harm done." Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the damage. A diesel fed petrol generally starts, idles and drives away as though nothing has happened, while your pump wears. Being able to run is not the same as being fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct issue. What petrol has diluted remains diluted, and that petrol remains in that tank regardless.
Myth: "Drain the tank yourself and you're sorted." After the engine has run, some of the petrol is no longer in the tank: it is in the filter and the fuel lines, and it goes right back through your pump on your next start. And, a can of petrol filled by the kerbside is truly risky.
How does petrol in a diesel happen?
No one does it on purpose, and it's rarely carelessness. A diesel nozzle generally will not fit a petrol car, but the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and only in that direction.
The moment habit stops matching your car is the moment it happens. Courtesy car, hire car, or a car that is new. A household with one petrol and one diesel on the driveway. The pumps in a different order on a familiar forecourt. A rushed fill en route to Theale with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it happens. Throw in rain, a phone call or a back seat full of children, and the hand does what it has always done.
Next time you fill up around Calcot Row: avoiding petrol in a diesel
- A green handle for unleaded and black for diesel is usual in the UK — yet not on every forecourt. Go by the label on the petrol pump, not the colour.
- The first fill in a new vehicle is the time to check the filler flap — inside it, or on the cap, many cars state the fuel they take.
- One of each in the household? Mark the key to your diesel — a coloured fob, a sticker — because intending to remember isn't enough.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump. It seems daft and it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away and keep your mind on the petrol pump.
- Some diesels come with a filler designed to refuse a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Stop the moment you realise. Less petrol in your tank means a thinner mix. It doesn't change what to do next, which is still not to start it.
Petrol already in a diesel in Calcot Row? Begin here
Short and simple, then, is the order of things. Don't switch the ignition on, and don't crank it. The staff on the forecourt — whether at BP itself or wherever you filled up — will normally help roll it clear of the pump if you ask. Ring 0333 366 0103 next, with three facts — your fuel, the rough quantity, and whether it's run.
If it was AdBlue and not petrol, say so. That is a different problem — corrosion and deposits instead of lost protection — and it has its own page for Calcot Row.
Why one petrol in a diesel job around Calcot Row costs more than another
A fair single price does not exist here: four situations, four separate jobs. Chiefly, the cost shifts with which situation you're in. Two things follow that: the petrol that went in as a share of what your tank holds, then the place your car is in and whether our van can get to it safely.
That's why our engineers ask three queries before quoting rather than after: what got in, how much, and whether it's run. A range turns into a straight figure once the answers are in.
About Calcot Row
Calcot Row is a suburban area situated on the riverside in Berkshire, with an elevation of around 60 metres. Calcot Row lies near the villages of Calcot and Little Heath, and is also close to Horncastle. Calcot Row is characterized by its predominantly detached housing stock, and is located approximately 23 miles from Oxford and 40 miles from London.
Fuel drain cover in Calcot Row and across Berkshire
Calcot Row rests in the RG postcode area, and the vans that answer petrol in diesel call-outs there work the spots around it as well — Calcot, Little Heath and Horncastle among them. No need to move the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations where we work.
In Calcot Row and still at the pump?
Then, you could not be in a better place. Keep it switched off, then ring.