Wood End: Petrol in a Diesel Car? How Worried to Be
Probably less than you already are — as long as no one has started the vehicle. Till the ignition primes the pump, the starter cranks, or the car is driven, petrol in a diesel tank simply waits there and does no harm. Which means the honest reply to that first Wood End question — "have I wrecked it?" — normally no. Keep it that way: leave your motor off then call Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and ways to make sure you never do it again.
Petrol in a diesel: what does it do to the motor?
Two tasks fall to diesel on its journey round a motor. Before it combusts, it protects — then it burns. Designed to very fine tolerances, the injectors and your pump depend on the diesel flowing through them to stop their surfaces wearing against one another.
Of those two tasks, petrol manages the first badly and the second not at all. A pump running on a petrol mixture is wearing itself out, because petrol is runnier than diesel and strips out the protection the fuel system depends on. Petrol is also made to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that is where the rattling comes.
Taken together, they show what shape the trouble takes. The damage is done by movement, not by contact. Where the petrol is only inside the tank, it's a fault of fuel, nothing more. The start of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with the fuel to your injectors downstream.
Four situations our technicians see around Wood End: how bad is petrol in a diesel?
Filled but never started — the best it gets. At a forecourt, and truly only there, the petrol is still limited to that tank — since everywhere else your car was driven to reach it. The task is emptying and purging on the spot.
A brief spell of running, or just your ignition on. Petrol has left that tank and reached your filter and your lines, because the system has been primed. Normally nothing more than emptying, flushing and seeing to the filter, so still simple.
A couple of miles driven, and your pump has spent each of them working on diluted fuel. Tank, lines, filter, then clean fuel run through the whole circuit: that's this work, and the way your car was driven counts as much as the miles. Short trips, like the school run to Wood End Primary School, are one matter. Getting as far as Lichfield, under 15 miles away, makes a very different task — as does any mileage on the M42, under a mile from Wood End, with your engine labouring hard all the way.
Clattering, an uneven idle, smoke, a throttle gone soft: driven until it complained. That is the motor telling you its fuel no longer is acting like diesel. Whether it is the verge on Tamworth Road, a lay-by or a side road, stop there and leave it. The fuel drain and flush still go first, and they sort it out: if a car is pulled over soon, long-term damage is very uncommon.
What Wood End motorists 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 fuller tank of the same mix. Percentage is not how a diesel fuel system copes with petrol, however much that advice assumes.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." Protection counts more on current diesels, not less, because their fuel passes through more precise components at higher pressure.
The myth that catches motorists out: if it starts and drives, it must be unharmed. Diesel in a petrol motor usually means a motor that will not run: the motorist stops, and so does the damage. A diesel fed petrol normally starts, idles and drives away as though nothing has happened, whilst the pump grinds. Fine and running aren't the same at all.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate fault. None of what petrol thinned gets put back by it — and afterwards, your tank still holds that petrol.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol sits in the fuel filter and lines, ready to go straight back through your pump on your next start. And, a can of petrol filled by the kerbside is genuinely risky.
Why petrol in a diesel occurs at all
Nobody does it on purpose, and it's rarely carelessness. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol motor. That is how the forecourt makes it easy.
The moment routine stops matching the vehicle is the moment it takes place. A new vehicle, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. Your ordinary forecourt, its pumps suddenly in a different order. Fuelling up in a hurry on the way to Wilnecote, with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it occurs. With rain, a call arriving, or children to deal with, your hand simply does what it has always done.
Next time you fill up in Wood End: preventing petrol in a diesel
- A green handle for unleaded and black for diesel is usual in the UK — but not on each forecourt. Trust the label on the pump, not the colour.
- Many motors state the fuel type inside the filler flap or on the cap, so check there on your first fill in any car you do not know.
- A coloured fob or a sticker on your diesel's key does more than any amount of intending to remember, in a house with one of each.
- "Diesel", out loud, before you lift the nozzle — each time a new or hired car needs its first tank. It seems daft. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away and keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to block a petrol nozzle, and add-on devices exist for cars without one. They are a safety net, not a reason to stop reading the pump.
- Noticing it halfway? Stop there and then. A thinner mixture follows from less petrol inside the tank, yet the next stage stays the same: don't fire it up.
Petrol already in a diesel around Wood End? Start here
Then the order of things is brief. Leave it unstarted, with the ignition off as well. Ask the attendants to help you roll it away from the pump if you are still at the forecourt, whether that is Esso or somewhere else. What was put in, roughly how much, and whether it has run: tell us those when you phone 0333 366 0103.
Say so if it was AdBlue rather than petrol: it's a different issue, with its own page for Wood End, because AdBlue brings corrosion and deposits rather than lost lubrication.
What makes one Wood End petrol in a diesel task cost more than the next
A fair single price doesn't exist here: four situations, four separate tasks. What shifts your cost is mostly which of them you're in. The share counts next, meaning how much of the tank is petrol, followed by the position of the vehicle and whether reaching it is safe for a technician.
What went in, how much, and if it's run — three queries we ask before pricing, not after, for exactly that reason. Given those answers, you get a straight figure instead of a range.
About Wood End and where it is
Wood End is a village in Warwickshire, situated on the riverside in the West Midlands region. Wood End has a population of around 1562 people and is characterized by semi-detached housing. Wood End sits at an elevation of 122 metres, near the villages of Freasley, Piccadilly, and Whateley, and is approximately 10 miles from Lichfield. Wood End is also within a reasonable distance from London, being around 98 miles away.
Fuel drain cover across Warwickshire, Wood End included
The teams answering petrol in diesel call-outs around Wood End, in the CV postcode area, equally work the places near it, Freasley, Piccadilly and Whateley included. The car doesn't need to move to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Wood End and still at the pump?
Then, you couldn't be in a better position. Leave it turned off, then ring.