Petrol in a Diesel Car in Letham: How Worried Should You Be?
Provided it hasn't been started, worry less than you probably are. Everyone in Letham starts with "have I wrecked it?", and the honest answer is normally no: petrol left inside that tank of any diesel remains harmless till priming, cranking or driving pulls it into your fuel system. Keep it like that: leave your motor off and ring Petrol in Diesel. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and the way to make sure you never repeat it.
The engine and petrol in a diesel: what goes on
Passing through an engine, diesel is doing two jobs at once. Before it combusts, it lubricates — then it combusts. What stops the surfaces inside your high-pressure pump and your injectors from grinding against each other is your diesel passing through them — they're designed to extremely fine tolerances.
The second task petrol doesn't do at all, and the first it does badly. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump running on the mixture wearing itself. It's equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the rattling.
Combined, those make the shape of the trouble clear. The damage is done by movement, not by contact. All a tank with petrol in it amounts to is a fuel issue. Once the pump has been running on that petrol, a mechanical problem has begun: whatever is shed by a pump that's grinding travels downstream to your injectors with your fuel.
Petrol in a diesel around Letham: how bad is it? Four situations
Filled up, and never started: no case is better. At a forecourt, and truly only there, the petrol is still confined to the tank — since everywhere else the car was driven to get to it. The task is draining and cleaning on the spot.
A moment's running, or just your ignition on. Once primed, your system has pulled petrol from that tank up to the filter and your lines. Still usually straightforward: drain, flush, and the filter seen to.
Driven a few miles. Now your pump has spent those miles labouring on weakened fuel. How hard the vehicle was driven matters as much as how far, and the work covers that tank, your lines, the fuel filter and clean fuel through the whole circuit. On the school run to the local primary school, the distance is small. A run as far as Perth, under 3 miles away, is a very different job. So is any miles on the M90, under 3 miles from Letham, where your engine has been working hard the whole time.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. What you are hearing is your motor signalling fuel that no longer runs like diesel. Whether it is the verge on Rannoch Road, a lay-by or a side road, stop where you are and leave it. Lasting damage is very rare when a car is pulled over early, and the fuel drain and flush that still come first deal with it.
Myths Letham motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you are left with a fuller tank, still the same mixture. Percentage isn't how a diesel fuel system copes with petrol, however much that advice assumes.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. More precise components and higher pressure are the way a newer diesel runs its fuel, and that makes the lubrication count more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches drivers. Diesel in a petrol motor usually leaves a motor that won't run: the motorist stops, and so does the damage. A diesel fed petrol usually starts, idles and drives away as though nothing has happened, while the pump wears. Running isn't 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 different fault. None of what petrol weakened is put back by it — and afterwards, your tank still contains that petrol.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol lies in the filter and lines, ready to go right back through the pump on the next start. And, a can of petrol filled by the roadside is genuinely hazardous.
Why petrol in a diesel happens so easily
It's seldom carelessness, and nobody does it on purpose. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle mostly won't go into a petrol vehicle at all. So the slip runs one way.
It happens when habit and the car stop matching. Hire cars, courtesy cars, and motors that are new to you. One petrol and one diesel on the drive of the same household. The pumps in a different order on a well-known forecourt. Filling up in a rush on the way to Perth, with a train to catch. Exactly the moment it happens: after years of driving petrol, someone fills a diesel Renault Megane for the first time. With rain, a call arriving, or a car full of children to deal with, your hand just does what it always has.
Next time you fill up in Letham: avoiding petrol in a diesel
- Green for unleaded and black for diesel is normal in the UK — but not on each forecourt. Go by the label on the pump, not the colour.
- The first fill in an unfamiliar motor is the time to check the filler flap — inside it, or on the cap, plenty of vehicles state the fuel to use.
- Mark 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.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump. It seems silly and it works.
- Put the phone away. This is an easy mistake to make while you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to reject a petrol nozzle, and add-on devices exist for motors without one. They are a safety net, not a reason to stop checking the pump.
- Spotting it mid-fill? Stop at once. A thinner mixture results from less petrol in your tank, but the next step remains the same: don't crank it.
Put petrol in a diesel in Letham already?
Then the order of things is short. Never start it, and do not switch the ignition on. If you're still on the forecourt — Tesco or anywhere else — ask the staff to help you roll the car away from the pump. What was put in, about how much, and whether it has run: tell us those when you call 0333 366 0103.
Corrosion and deposits form the trouble with AdBlue, where petrol brings lost protection. So if it was AdBlue, say so — and see its own Letham page.
Letham petrol in a diesel jobs: why one costs more than another
A fair single price doesn't exist here: four situations, four separate tasks. The situation itself does most of the work of moving the cost. The ratio counts next, meaning how much of the tank is petrol, followed by the location of your car and whether getting to it is safe for our van.
What was put in, how much, and whether it's run — three questions we ask before costing, not after, for exactly that reason. Those replies are what change a range into one firm number.
About Letham and its setting
Letham is a suburban area located near Perth in Perth and Kinross, sitting at an elevation of 42 metres in the inland setting of the Scottish countryside. Letham is close to several nearby places, including Burghmuir, Hillyland, and Tulloch, and is situated approximately 1.2 miles from Perth. Letham has a population of around 7540 people, predominantly residing in flat-type housing.
Across Perth and Kinross and in Letham: fuel drain cover
Our vans answering petrol in diesel calls around Letham, in the PH postcode area, also work the locations around it, Burghmuir, Hillyland and Tulloch included. You need not move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations we drain.
Still at the pump in Letham?
Then you're in the best place there is. Turned off it remains; then call.