How Worried Should You Be? Petrol in a Diesel Car in Rydeshill
Not started? Then less anxious than you likely feel. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through the system — the ignition priming the pump, your starter, or the drive on its own. So the honest answer to the first question anyone in Rydeshill asks, "have I ruined it?", is usually no. Leave the motor off then ring Petrol in Diesel — that is how you keep it like that. Below, this page sets out what petrol actually does inside a diesel, how far it might have gone, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to the motor?
Diesel has two jobs on its way through an engine. It protects first, and only then does it burn. Built to extremely fine clearances, the injectors and your pump depend on the diesel moving through them to stop their surfaces wearing against one another.
The second job petrol doesn't do at all, and the first it does badly. A pump running on a petrol blend is wearing itself out, since petrol is thinner than diesel and strips out the lubrication the fuel system relies on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that is where the rattling comes.
Put those together and the shape of the issue is clear. It is circulation that does the damage, not contact. All a tank with petrol in it amounts to is a fuel issue. A pump that has been labouring on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to your injectors further on.
Petrol in a diesel around Rydeshill: how bad is it? Four cases
Filled up, and never started: no case is better. Only that tank has petrol in it, so the job is draining the tank and flushing the system where your car stands. This scenario can only truly occur at a forecourt: anywhere else, the car got there by being driven.
Started for a second, or just the ignition on. With your system primed, your lines and filter now hold petrol that came from your tank. That is generally still a straightforward job — a drain, a flush, and the fuel filter dealt with.
The pump has spent a few miles on thinned fuel — that is what driving the car meant. Tank, lines, filter, then fresh fuel run through the entire circuit: that is the work, and the way your car was driven matters as much as the mileage. Short trips, such as the school run to St Joseph's Catholic Primary School, are one thing. Getting as far as Westminster, under 50 miles away, makes a very different job — as does any mileage on the M3, under 10 miles from Rydeshill, with the motor labouring hard the whole time.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone uneven. That's your motor telling you its fuel has stopped acting like diesel. Leave it where it stops: a lay-by, a quiet street, the verge on Broad Street. A vehicle stopped early very rarely has permanent damage, since the fuel drain and the flush-through, which still go first, deal with it.
Rydeshill motorists and that petrol in a diesel stories they hear
Myth: topping up to full with diesel makes it fine. It does not. Topping up takes out nothing; it gives you a fuller tank of the same mix. Percentage isn't how a diesel fuel system tolerates petrol, however much that advice presumes.
Not so: a current diesel copes with a bit of petrol. Rather, the reverse. Lubrication matters more on newer diesels, not less, because their fuel passes through finer parts at higher pressure.
Myth: "If it starts and drives, there's no damage done." This is the one that fools drivers. Feed diesel to a petrol engine and it generally will not run, so the motorist stops — and the harm stops with them. A diesel fed petrol generally starts, idles and drives away as though nothing has happened, while your pump grinds. Running doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate issue. What petrol has weakened remains thinned, and the petrol remains inside your tank regardless.
The next start sends petrol back round the pump out of your lines and your filter, where some of that sits after the engine has run. That is why draining the tank yourself doesn't leave you sorted — a myth. It is also really hazardous to drain petrol into a can by the roadside.
How it happens: petrol in a diesel
Nobody does it on purpose, and it is rarely carelessness. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol car. That is how the forecourt makes it straightforward.
It takes place when routine and your car stop matching. Hire cars, courtesy cars, and vehicles that are new to you. One petrol and one diesel on the drive of the same household. Your usual forecourt, its pumps suddenly in a different order. A rushed fill on the way to Guildford with a train to catch. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. Throw in a back seat full of kids, a phone call or rain, and habit wins.
How to avoid petrol in a diesel on your next fill-up around Rydeshill
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Read the pump's label; the colour is only a hint.
- Inspect your filler flap. Plenty of cars state the fuel inside the flap or on the cap. Look at it on the first fill in a motor you do not know.
- Mark the key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- It seems silly and it does the trick: on the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump.
- Whilst you're thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Add-on devices are available for cars without one, and some diesels are built with a filler that won't take a petrol nozzle. Helpful — but a safety net at best, never a reason to stop checking the label.
- Less petrol makes a weaker mix, and so stop as soon as you realise — though remembering that your next step is unchanged. It is still not to start it.
Already put petrol in a diesel in Rydeshill?
Short and simple, then, is the order of things. Don't turn the ignition on, and do not fire it up. The attendants on the forecourt — whether at Shell itself or wherever you filled up — will normally help push it clear of the pump if you ask. What went in, about how much, and if it has run: tell us those when you ring 0333 366 0103.
Corrosion and deposits are the problem with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and see its own Rydeshill page.
One petrol in a diesel task around Rydeshill costs more than another. Why?
An honest single quote doesn't exist here: four scenarios, four separate jobs. What shifts your cost is mostly which of them you're in. Beyond that it is the ratio — how much petrol went in against how much the tank takes — and after that where the vehicle is and whether a van can reach it safely.
What went in, how much, and whether it's run — three questions our technicians ask before costing, not after, for exactly that reason. With those replies, you get a straight figure instead of a range.
About Rydeshill
Rydeshill is a suburban area in Surrey, situated approximately 27 miles southwest of central London. Rydeshill sits at a relatively low elevation of around 50 metres, near the neighbouring areas of Stoughton and Park Barn. Rydeshill is characterized by its predominantly semi-detached housing stock, reflecting the typical residential development patterns of the South East region. Rydeshill has a population of around 5401 residents, according to recent estimates.
Fuel drain cover across Surrey, Rydeshill included
Stoughton, Park Barn and Westborough are among the locations near Rydeshill that the same teams work, answering petrol in diesel jobs across Rydeshill's GU postcode area. A forecourt, a supermarket car park, a lay-by or your own drive are all locations our engineers drain, and your car does not need to come to us.
In Rydeshill and still at the petrol pump?
In that case, you couldn't be in a better place. Turned off it stays; then phone.