Petrol in a Diesel Car in Penninn: How Worried Should You Be?
Less than you likely are, if it hasn't been started. Everyone in Penninn starts with "have I ruined it?", and the fair answer is normally no: petrol resting in that tank of any diesel stays harmless until priming, cranking or driving draws it into the fuel system. Leave the motor off and phone Petrol in Diesel — that is how you keep it that way. Read on for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and ways to make sure you never do it again.
What petrol in a diesel does to your engine
Passing through a motor, diesel does two things at once. It protects to begin with, and after that does it burn. Very fine clearances go into the fuel injectors and the high-pressure fuel pump, and just your diesel running through stops those surfaces grinding together.
Poorly at the first, not at all at the second: that's petrol. It is thinner than diesel and takes away the protection the fuel system depends on, so a pump running on a petrol mix is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the rattling comes from.
Seen together, they make clear the shape the problem takes. Not contact but circulation is what causes the damage. Any tank with petrol in it is a fuel fault. The beginning of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to your injectors downstream.
Petrol in a diesel in Penninn: how serious is it? Four cases
The best case there is: filled up, not once started. Just the tank has petrol in it, so the job is clearing that tank and flushing your system where the car sits. This scenario can only truly take place on a forecourt: anywhere else, the vehicle got there by being driven.
Ignition on, or started for a moment. The fuel system has been primed, so petrol has left your tank and got to the filter and your lines. Normally nothing more than draining, cleaning and sorting your filter, and so still easy.
Driven a couple of miles. Now the pump has spent those miles working on weakened fuel. Miles is only half of it; how hard it was driven counts just as much. Either way this work runs to that tank, the lines, the fuel filter and fresh fuel through the entire system. Short trips, such as the school run to Haytor View Community Primary School, are one matter. A run as far as Exeter, under 15 miles away, is a very different job. So is any miles on the M5, under 15 miles from Penninn, where the motor has been labouring hard throughout.
Knocking, a lumpy idle, smoke, a throttle gone soft: driven till it complained. That's the motor telling you its fuel has stopped behaving like diesel. Whether it is the verge on Shaldon Road, a lay-by or a side road, stop where you are and leave it. What goes first is still the fuel drain and flush-through, and that deals with it, with lasting damage very uncommon when a car is stopped early.
What Penninn drivers get told about petrol in a diesel — and the myths in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." A fuller tank of the same mixture is all you get, because topping up takes out nothing. A diesel fuel system does not tolerate petrol by percentage in the way that advice assumes.
Myth: a modern diesel copes with a bit of petrol. If anything, the reverse. A newer diesel runs its fuel through finer parts at higher pressure, which makes the lubrication count more, not less.
One myth that catches motorists off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol motor and it generally won't run, and so the motorist stops — and the harm stops with them. Feed petrol to a diesel and it normally fires up, ticks over and drives away like nothing happened — all the while its pump wears. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate issue. What petrol has diluted remains diluted, and that petrol stays in the tank regardless.
If your engine has been run, part of the petrol is in the filter and the fuel lines, not your tank — and the next start sends it straight back through the pump. So the myth "drain that tank yourself and you're sorted" does not hold. On top of that, petrol cleared into a can by the road is genuinely hazardous.
Petrol in a diesel: how does it occur?
On purpose? Never. Through carelessness? Rarely, if ever. One way only, since of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one mostly will not fit a petrol car. That is how the forecourt makes it easy.
When habit and your car stop matching, it happens. Any car that is new to you — a hire car, on loan as a courtesy car, or just bought. One petrol and one diesel on the drive of the same household. Your normal forecourt, its pumps suddenly in a different order. Fuelling up in a hurry on the way to Newton Abbot, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist accustomed to petrol: precisely when it happens. The hand does what it has always done when you add rain, a phone call or a back seat full of children.
Next time you fill up around Penninn: preventing petrol in a diesel
- Read the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on every forecourt. The label is what matters.
- The first fill in a new car is the time to check the filler flap — on it, or on the cap, many motors state which fuel to use.
- Label your 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 meaning to remember.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car needs its first tank. It sounds daft. It does the trick.
- Mistakes like this are easy to make while your mind is on something else, and so the phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to block a petrol nozzle, and aftermarket devices are available for the rest. Treat it as a safety net, then keep checking the petrol pump.
- Stop the moment you realise. Less petrol inside that tank means a weaker mixture. It doesn't change what to do next, which is still not to fire it up.
Petrol already in a diesel around Penninn? Begin here
Then the order of things is short. Starting it is out, and so is switching on the ignition. If you're still at the forecourt — Sainsbury's or anywhere else — ask the staff to help you roll the car away from the pump. Next, 0333 366 0103. We'll ask what went in, about how much, and if it's been run.
Corrosion and deposits are the problem with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and read its own Penninn page.
Why one petrol in a diesel task in Penninn costs more than another
The four scenarios above are four separate tasks, so no single price for this would be honest. What moves the cost is mostly which of them you're in. Where the car is matters too, and whether a technician can safely reach it, after the proportion of petrol to what the tank takes.
That's why our technicians ask three queries before costing rather than after: what was put in, how much, and if it has run. Given the answers, you get a straight figure instead of a range.
About Penninn itself
Penninn is a suburban area located on the riverside in Devon, with a relatively low elevation of 8 metres. Penninn sits near the cities of Exeter and other nearby places such as Milber and Aller Park. Penninn has a population of approximately 4289 residents, predominantly living in semi-detached housing. Penninn is situated in a region that is about 165 miles from London, but is more closely tied to the local city of Exeter, which is about 14 miles away.
Across Devon and around Penninn: fuel drain cover
Our teams answering petrol in diesel jobs in Penninn, in the TQ postcode area, also work the places around it, Milber, Aller Park and Buckland among them. You need not bring the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots we drain.
At the petrol pump in Penninn, still?
In that case, you could not be in a better position. Phone, and leave it switched off.