How Worried Should You Be? Petrol in a Diesel Car in Mellor
Less than you likely are, provided it hasn't been started. Petrol resting in a diesel tank does nothing to the engine until something pulls it through your fuel system — the ignition priming your pump, your starter, or driving on its own. So the honest answer to the first question everyone around Mellor asks, "have I wrecked it?", is generally no. Keep it that way: leave your motor off then call Petrol in Diesel. The remainder of this page covers what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you again.
Petrol in a diesel: what does it do to the engine?
Diesel has two tasks on its way through an engine. It lubricates first, and after that does it burn. Your high-pressure pump and the fuel injectors are built to extremely fine gaps, and your diesel passing through them is what keeps those surfaces from wearing down against one another.
Of those two jobs, petrol handles the first poorly and the second not at all. A pump working on a petrol mix is wearing itself out, because petrol is runnier than diesel and strips out the protection the fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that is where the knocking comes.
Combined, those leave the shape of the issue plain. Contact does not do the harm — movement does. All a tank with petrol in it amounts to is a fuel problem. A pump that has been working on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the fuel injectors further on.
How bad is petrol in a diesel? Four scenarios we see around Mellor
Filled up, not once started. The best case there is. That petrol is in the tank and only that tank, and the job is a drain and a flush where your car sits. This is the one scenario that can only really take place at a forecourt, because anywhere else the vehicle has been driven to get there.
Started for a second, or just the ignition on. Petrol has come out of that tank and got to the fuel filter and the lines, because the system has been primed. That's usually still a simple job — a drain, a flush, and the filter seen to.
Your pump has worked a couple of miles on thinned fuel — that's what driving the car meant. How hard your car was driven matters as much as how far, and the work takes in that tank, the lines, the filter and fresh fuel through the entire circuit. Driving the children to Mellor St Mary Church of England Primary School is one kind of trip. Very different a second time: a run to Preston, under 10 miles away, or any miles on the M65, under 5 miles from Mellor, where the engine never stopped working hard.
Knocking, an uneven idle, smoke, a throttle gone soft: driven until it complained. The fuel isn't behaving like diesel any more, and your engine is telling you. Whether it is the verge on Thwaites Avenue, a lay-by or a side street, stop there then leave it. The fuel drain and flush still come first, and they sort it out: if a vehicle is stopped early, long-term damage is very rare.
What Mellor drivers get told about petrol in a diesel — and the myths in it
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed when you top up — that tank simply carries more of the same blend. Percentage isn't how a diesel fuel system tolerates petrol, whatever that advice assumes.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. A modern diesel sends its fuel through finer components at higher pressure, which makes the protection matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there is no harm done." The driver of a petrol motor fed diesel usually stops, because it will not run, and the harm stops there. A diesel fed petrol usually starts, ticks over and drives away as if nothing has happened, while the pump grinds. Running does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate issue. None of what petrol weakened gets put back by it — and afterwards, your tank still contains that petrol.
The next start draws petrol back round the pump out of your lines and your filter, where some of that ends up after the motor has been run. That's why draining your tank yourself doesn't leave you sorted — a myth. Besides, petrol drained into a can by the road is genuinely hazardous.
Petrol in a diesel: how does it take place?
It is rarely carelessness, and no one does it on purpose. The forecourt makes it simple: the petrol nozzle is the slimmer of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle mostly will not go into a petrol motor at all. So the error runs one way.
When routine and the car stop matching, it takes place. Any car that's new to you — a hire car, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. A train to catch, and a hurried fill on the way to Ramsgreave & Wilpshire. A new-to-you diesel Skoda Octavia, its first fuelling, and a driver used to petrol: precisely when it happens. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
Next time you fill up in Mellor: avoiding petrol in a diesel
- The label is what counts, and so read the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, yet not on every forecourt.
- Check the filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on your first fill in any vehicle you don't know.
- One of each in the household? Label the key to your diesel — a coloured fob, a sticker — because meaning 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 take the nozzle off the pump. It seems silly and it works.
- While you are thinking about something else, this is an easy mistake to make — so tuck the 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 are available for cars without one. They are a safety net, not a reason to stop reading the petrol pump.
- As soon as you notice, stop: less petrol in that tank makes a weaker blend. What to do next does not change, though — still don't crank it.
Already put petrol in a diesel around Mellor?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition off too. If you are still at the forecourt — SPAR Pennine Service Station or anywhere else — ask the attendants to help you roll the vehicle clear of the petrol pump. What went in, about how much, and whether it has run: tell us those when you call 0333 366 0103.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate fault — Mellor has a page all for it.
Mellor petrol in a diesel jobs: why one costs more than another
There is no fair single price for this, since the four situations above are four different tasks. Which of them you are in is mostly what moves your cost. Two things follow that: the petrol that went in as a share of what your tank takes, then the place the vehicle is in and whether a technician can get to it safely.
That is why our technicians ask three questions before costing rather than after: what was put in, how much, and whether it has run. With those answers, you get a straight figure rather than a range.
About Mellor
Mellor is a village in Lancashire, situated inland at an elevation of 177 metres, approximately 6.9 miles from Preston. Mellor has a population of around 1448 people, predominantly living in detached houses. Mellor is close to nearby places such as Mellor Brook, Osbaldeston, and Lammack, and is located in the North West region of England, about 186.1 miles from London.
Mellor and Lancashire: where our fuel drain cover reaches
Mellor Brook, Osbaldeston and Lammack are among the places around Mellor that the same vans work, answering petrol in diesel jobs across Mellor's BB postcode area. A forecourt, a supermarket car park, a lay-by or your own drive are all places our engineers drain, and your car does not need to come to us.
In Mellor and still at the pump?
Then you're in the best place there is. Keep it off. Call.