Should You Worry? Petrol in a Diesel Car in Blackheath Park
Unstarted? Then less worried than you likely are. Until your ignition primes your pump, your starter turns, or your vehicle is driven, petrol in a diesel tank simply rests there and does nothing. Which makes the honest reply to that first Blackheath Park query — "have I ruined it?" — usually no. Leave the engine off then call Petrol in Diesel — that is how you keep it that way. The remainder of this page explains what petrol really does to a diesel, how to tell 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 your engine?
Two tasks fall to diesel on its route round a motor. It ignites, and before it burns it lubricates. Extremely fine tolerances go into the injectors and your high-pressure pump, and just your diesel running through stops those surfaces grinding together.
Badly at the first, not at all at the second: that's petrol. It is runnier than diesel and removes the lubrication the system hinges on, and so a pump running on a petrol mixture is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the rattling comes from.
Combined, those leave the shape of the problem plain. It is circulation that causes the damage, not contact. All a tank with petrol in it amounts to is a fuel problem. 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 your fuel to your injectors downstream.
How serious is petrol in a diesel? Four situations our technicians see in Blackheath Park
Fuelled but never started — the best it gets. The petrol is in your tank and only that tank, and the task is a drain and a flush where the vehicle stands. This is the one situation that can only really take place on a forecourt, because anywhere else the car has been driven to get there.
Your ignition turned on, or a brief start. Petrol has come out of your tank and reached the filter and the lines, because your system has been bled. Usually nothing more than clearing, rinsing and sorting the filter, and so still easy.
The pump now worked a few miles on thinned fuel — that's what driving the vehicle meant. The work is your tank, the fuel lines, the fuel filter and clean fuel through the entire system, and how hard the car was driven counts as much as how far. Short trips, like the school run to John Ball Primary School, are one thing. Very different once more: a trip to London, under 10 miles away, or some mileage on the M11, under 10 miles from Blackheath Park, where the motor never stopped working hard.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The engine is telling you the fuel is no longer behaving like diesel. Leave it where it stops: a lay-by, a quiet street, the verge on Blackheath Park. Permanent damage is very unusual when a car is pulled over soon, and the fuel drain and flush-through that still go first deal with it.
Petrol in a diesel stories Blackheath Park people hear
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. That guidance supposes a diesel fuel system handles petrol by percentage. It doesn't.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. Lubrication counts more on newer diesels, not less, since their fuel runs through more precise parts at higher pressure.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol motor and it normally will not run, and so the driver stops — and the harm stops with them. Feed petrol to a diesel and it usually starts, idles and drives away as if nothing happened — all while its pump wears. Fine and running are not the same thing.
An old workaround for a distinct problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has weakened stays thinned, and that petrol stays in that tank anyway.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol lies in your filter and lines, waiting to go right back through your pump at your next start. Emptying petrol into a can by the kerbside is also genuinely dangerous.
Petrol in a diesel: how does it take place?
Carelessness is rarely the cause, and nobody means to do it. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one mostly won't fit a petrol vehicle. That's how the forecourt makes it straightforward.
It takes place when habit and the car stop matching. Any car that is new to you — a hire car, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. Your usual forecourt, its pumps suddenly in a different order. Fuelling up in a hurry en route to Blackheath, with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a motorist used to petrol: precisely when it occurs. With rain, a call coming in, or a car full of children to deal with, your hand just does what it has always done.
Next time you fill up in Blackheath Park: preventing petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what matters.
- Plenty of cars state the fuel type inside your filler flap or on the cap, so check it on your first fill in any car you do not know.
- Mark your key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- Before the nozzle leaves the pump the first time you fill a hired or new motor, say "diesel" aloud. Silly, perhaps, but it works.
- Tuck your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to refuse a petrol nozzle, and add-on devices exist for the remainder. Count it as a safety net, then keep checking the petrol pump.
- Stop as soon as you notice. Less petrol in the tank means a thinner blend. It does not change what to do next, which is still not to crank it.
Already put petrol in a diesel in Blackheath Park?
Then the order of things is short. Starting it is out, and so is switching on your ignition. If you're still on the forecourt — BP or anywhere else — ask the staff to help you push the vehicle clear of the pump. Ring 0333 366 0103 next, with three facts — your fuel, the rough amount, and if it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different issue — Blackheath Park has a page just for it.
Why one petrol in a diesel task around Blackheath Park costs more than another
A fair single quote doesn't exist here: four situations, four separate tasks. Which of them you're in is mostly what shifts the cost. After that it is the share — how much petrol went in against how much the tank holds — and then where your car is and whether a technician can get to it safely.
Ahead of any quote, not after, we ask three questions: your fuel that got in, the volume, and whether it's run. That is why. Those replies change a range into a straight figure.
About Blackheath Park and its setting
Blackheath Park is a suburban area in south east London, situated near the River Thames at an elevation of around 37 metres. Blackheath Park is characterized by its predominantly flat housing stock, with many residents enjoying views of the surrounding area. Blackheath Park is close to several nearby places, including Blackheath Royal Standard, Blackheath, and Lee, and is approximately 6.6 miles from central London.
Fuel drain cover across Greater London, Blackheath Park included
Blackheath Royal Standard, Blackheath and Lee are among the spots around Blackheath Park that the same vans work, answering petrol in diesel call-outs across Blackheath Park's SE postcode area. We drain wherever the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the petrol pump around Blackheath Park, right now?
Then, you couldn't be in a better position. Leave it turned off, then ring.