Middle Park: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — as long as nobody has started the car. Everyone in Middle Park starts with "have I ruined it?", and the fair answer is usually no: petrol resting in that tank of a diesel stays harmless until priming, cranking or driving draws it into your fuel system. To leave it that way, ring Petrol in Diesel then leave your engine alone. Read on for three things: the effect petrol has inside a diesel motor, the clues of how far it has spread, and the way to make sure you don't repeat it.
The engine and petrol in a diesel: what happens
Passing through a motor, diesel is doing two things at once. It burns, and before it burns it lubricates. Very fine clearances are built into your injectors and the high-pressure pump, and only your diesel running through stops those surfaces grinding together.
The second task petrol doesn't do at all, and the first it does badly. Being less viscous than diesel, petrol strips away the protection a fuel system needs, so a pump running on the mixture wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the rattling.
Put those together and the shape of the trouble is plain. Contact doesn't do the harm — circulation does. Any tank with petrol in it is a fuel fault. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to your injectors further on.
Middle Park, petrol in a diesel: four cases, from mild to serious
Fuelled but never started — the best it gets. Just that tank has petrol in it, so the task is clearing that tank and cleaning the fuel system where your car sits. This scenario can only really happen at a forecourt: anywhere else, the vehicle got there by being driven.
Started for a moment, or only your ignition on. With the system primed, your lines and filter already hold petrol that came from your tank. That is generally still a simple job — a drain, a flush, and your filter seen to.
The pump has spent a couple of miles on thinned fuel — that is what driving the car meant. Distance is only half of it; how hard it was driven matters equally. Either way this work runs to that tank, your lines, the filter and clean fuel through the entire system. A school run to Middle Park Primary School is one matter. Any miles on the M20, under 10 miles from Middle Park, means your engine working hard throughout, and a run to London, under 10 miles away, is a very different task too.
Rattling, a ragged idle, smoke, a throttle gone soft: driven till it complained. That is your engine telling you its fuel no longer is behaving like diesel. Whether it's the verge on Newmarket Green, a lay-by or a side road, stop there then leave it. A vehicle pulled over quickly very rarely has long-term damage, because the drain and the flush, which still come first, deal with it.
Myths Middle Park drivers hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed by topping up — you're left with a fuller tank, still the same mixture. A diesel fuel system doesn't accept petrol by percentage in the way that guidance presumes.
Not so: a newer diesel copes with a bit of petrol. If anything, the opposite. Lubrication counts more on modern diesels, not less, since their fuel passes through smaller parts at higher pressure.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. The motorist of a petrol engine fed diesel usually 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 the pump grinds. Running doesn't mean fine.
Myth: "Add some two-stroke oil and drive it home." It is an old fix for a distinct issue. It does not put back what petrol has thinned, and that petrol is still in the tank later.
"Drain it yourself and you are sorted" — a myth, since after it has been running some petrol sits in the fuel filter and lines, waiting to go straight back through your pump at the next start. Also, a can of petrol filled at the roadside is genuinely hazardous.
How does petrol in a diesel take place?
A careless moment is seldom the cause, and no one means to do it. One way only, because of the nozzles: the smaller petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally will not fit a petrol car. That's how the forecourt makes it easy.
The moment habit stops matching your car is the moment it happens. A motor that is new to you — hired, on loan as a courtesy car, or brand new. One petrol and one diesel on the drive 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 Mottingham. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: precisely when it takes place. With rain, a call coming in, or a car full of children to deal with, your hand simply does what it always has.
Next time you fill up in Middle Park: preventing petrol in a diesel
- Green for unleaded and black for diesel is usual in the UK — yet not on each forecourt. Trust the label on the pump, not the colour.
- Check the filler flap. Plenty of cars state the fuel inside the flap or on the cap. Look at it on the first fill in any vehicle you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember, for a house with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. It sounds silly and it does the trick.
- While you're thinking about something else, this is an easy mistake to make — so put your phone away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop reading the petrol pump.
- Less petrol means a thinner blend, so stop as soon as you realise — while remembering that the next step is unchanged. It is still not to start the vehicle.
Put petrol in a diesel in Middle Park already?
In that case, there is only a short order of things. Do not crank it, and don't turn the ignition on. If you're still on the forecourt — BP or anywhere else — ask the attendants to help you roll the vehicle away from the petrol pump. Then ring 0333 366 0103 and tell us what went in, about how much, and whether it has run.
Corrosion and deposits are the trouble with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and see its own Middle Park page.
What makes one Middle Park petrol in a diesel job cost more than the next
An honest single price does not exist here: four scenarios, four separate jobs. The situation itself does most of the work of moving your cost. Next it is the share — how much petrol got in against how much that tank holds — and then where your car is and whether our van can get to it safely.
Before any quote, not after, come three queries: the fuel that was put in, the quantity, and whether it has run. That's why. The answers change a range into a straight figure.
About Middle Park, briefly
Middle Park is a suburban area in south east London, situated on the riverside at an elevation of 44 metres. Middle Park is located near several other local areas, including Horn Park, Eltham, and Well Hall. Middle Park is characterized by its predominant housing type, which is flats, and it is home to a population of approximately 4801 residents. Middle Park is also relatively close to central London, being around 8.4 miles away.
Fuel drain cover around Middle Park and across Greater London
Horn Park, Eltham and Well Hall are among the locations near Middle Park that the same vans work, answering petrol in diesel call-outs across Middle Park's SE postcode area. The car doesn't need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the petrol pump in Middle Park?
In that case, you could not be in a better position. Leave it turned off, then ring.