Should You Worry? Petrol in a Diesel Car in Kirkhill
Unstarted? Then less anxious than you likely feel. Until your ignition primes your pump, your starter cranks, or your car is driven, petrol in a diesel tank just sits there and does no harm. Which means the honest reply to that first Kirkhill query — "have I wrecked it?" — usually no. Petrol in Diesel is who to ring, with your motor left off, and so it stays that way. What petrol really does to a diesel, how to judge how far it has gone, and how to keep it from happening a second time: that is the remainder of this page.
Inside the motor: what petrol in a diesel really does
Two jobs fall to diesel on its journey through a motor. It protects to begin with, and after that does it burn. Very fine tolerances go into the fuel injectors and the high-pressure pump, and just the diesel running through stops those surfaces grinding together.
Petrol handles the first task poorly and the second not at all. It is thinner than diesel and takes away the lubrication the fuel system hinges on, so a pump running on a petrol blend 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 knocking comes from.
Taken together, they show the shape the issue takes. It is circulation that does the harm, not contact. All a tank with petrol in it amounts to is a fuel issue. After the pump has been labouring on that petrol, a mechanical problem has begun: anything shed by a pump that's grinding is carried downstream to your injectors with the fuel.
Four situations our technicians see around Kirkhill: how bad is petrol in a diesel?
Filled up, not once started. The best case there is. Just that tank has petrol in it, so the job is emptying that tank and cleaning the system where your car stands. This situation can only truly occur at a forecourt: anywhere else, the vehicle got there by being driven.
Ignition on, or started for a second. The system has been bled, and so petrol has left your tank and reached the fuel filter and the lines. Still generally simple: drain, flush, and the filter dealt with.
Driven a couple of miles. Now the pump has spent those miles labouring on thinned fuel. How hard the car was driven counts as much as how far, and the work covers that tank, the lines, your filter and fresh fuel through the entire system. Driving the kids to the local primary school is one kind of trip. Very different again: a run to Edinburgh, under 10 miles away, or some distance on the M8, under 10 miles from Kirkhill, where your engine never stopped working hard.
Driven until it protested. Rattling, a ragged idle, smoke, a throttle that has gone soft. That is the motor telling you its fuel no longer is acting like diesel. Pull up wherever you are — the verge on Windsor Lane, a lay-by, a side street — then leave the car where it is. The drain and flush still come first, and they sort it out: if a car is pulled over soon, long-term damage is very uncommon.
Myths Kirkhill motorists hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing is removed when you top up — that tank just carries more of the same blend. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance presumes.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." A current diesel sends its fuel through smaller parts at higher pressure, which makes the protection matter more, not less.
"It starts, it drives, and so there is no harm" — the myth that trips up more drivers than any other. A petrol motor fed diesel normally will not run, so the driver stops and the harm stops with them. A diesel fed petrol usually starts, idles and drives away as if nothing has happened, while the pump grinds. Running is not the same as fine.
An outdated fix for a different problem is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." It does not put back what petrol has diluted, and the petrol is still in the tank later on.
The next start sends petrol back round your pump from the lines and the filter, where some of that sits once the engine has been run. That is why a DIY tank drain does not leave you sorted — a myth. It is also really dangerous to drain petrol into a can at the roadside.
How does petrol in a diesel occur?
Carelessness is seldom the cause, and no one means to do it. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle mostly won't go into a petrol motor at all. So the slip runs one way.
It occurs when routine and the vehicle stop matching. Any vehicle that is new to you — a hire car, on loan as a courtesy car, or brand new. Two motors on one driveway, one petrol, one diesel. A well-known forecourt with the pumps in a different order. A rushed fill on the way to Newtongrange with a train to catch. The first fill-up in a diesel Skoda Octavia after years of driving petrol is precisely the moment it happens. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it has always done.
How to prevent petrol in a diesel at your next fill-up in Kirkhill
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Check the petrol pump's label; the colour is just a clue.
- The first fill in a strange car is the time to check your filler flap — on it, or on the cap, many cars state which fuel to use.
- Mark your key. In a home with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car needs its first tank. It seems silly. It works.
- Tuck the phone away. This is an easy mistake to make while you're thinking about something else.
- Some diesels come with a filler built to block a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- As soon as you notice, stop: less petrol in that tank means a weaker blend. What to do next does not change, though — still don't start the vehicle.
Put petrol in a diesel around Kirkhill already?
Then, there is only a short order of things. Leave it unstarted, with your ignition switched off as well. Ask the staff to help you roll it clear of the petrol pump if you are still at the forecourt, whether that is Tesco or anywhere else. Phone 0333 366 0103 next, with three facts — your fuel, the approximate volume, and whether it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate problem — Kirkhill has a page all for it.
Why one petrol in a diesel task in Kirkhill costs more than another
Four separate tasks lie behind the four scenarios above — which is why there is no honest single quote. The scenario itself does most of the work of moving your cost. Where your car is matters too, and whether our van can safely reach it, after the share of petrol to what the tank holds.
Three queries come first, before quoting, rather than after — what was put in, how much, has it run — and that is the reason. Their replies are what turn a range into one firm number.
About Kirkhill and its setting
Kirkhill is a suburban area situated on the riverside in Midlothian, with a mix of terraced housing and a population of around 3951 residents. Kirkhill sits at an elevation of 186 metres, approximately 8.5 miles from Edinburgh, and is near other local places such as Eskhill and Ladywood. Kirkhill is part of the wider commuter belt around Edinburgh, with easy access to the city and its amenities. Kirkhill's location also makes it a relatively long distance from London, at around 324 miles.
Across Midlothian and in Kirkhill: fuel drain cover
The teams answering petrol in diesel call-outs around Kirkhill, in the EH postcode area, equally work the locations near it, Eskhill, Ladywood and Loanburn among them. No need to move the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
Kirkhill: still at the pump?
Then, you could not be in a better position. Phone, and keep it switched off.