How Worried Should You Be? Petrol in a Diesel Car in Shawsburn
Probably less than you already are — as long as no one has started the vehicle. "Have I wrecked it?" is the first thing anyone in Shawsburn asks, and the honest answer is generally no, since petrol resting in a diesel tank harms nothing till it's drawn through the system — by ignition priming, by the starter, or by driving. Petrol in Diesel is who to call, with your motor left off, and so it stays that way. What petrol really does to a diesel, how to judge how far it's travelled, and how to keep it from happening again: that is the remainder of this page.
Inside the motor: what petrol in a diesel really does
On its way through a motor, diesel does two jobs. Before it combusts, it lubricates — and then it combusts. What stops the surfaces inside the high-pressure fuel pump and the injectors from wearing against one another is your diesel flowing through them — they're designed to very fine clearances.
Poorly at the first, not at all at the second: that is petrol. A pump working on a petrol mixture is wearing itself out, because petrol is thinner than diesel and strips out the lubrication the fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where the clattering starts.
The shape of the problem is plain once you put those together. Not contact but movement is what does the damage. A tank with petrol in it is a fuel issue. Once the pump has been labouring on that petrol, a mechanical problem has started: whatever is shed by a pump that's wearing travels onward to the injectors with your fuel.
Four situations our engineers see in Shawsburn: how bad is petrol in a diesel?
The best case there is: filled up, never started. Only the tank has petrol in it, so the task is draining the tank and flushing your system where the car sits. This situation can only really happen on a forecourt: anywhere else, the vehicle got there by being driven.
Your ignition turned on, or a brief start. Once primed, your system has drawn petrol out of your tank as far as the fuel filter and the lines. That is generally still a simple task — a drain, a flush, and the fuel filter seen to.
Your pump now spent a couple of miles on thinned fuel — that is what driving the car meant. Mileage is only half of it; how hard it was driven matters equally. Either way this work includes that tank, the fuel lines, the fuel filter and clean fuel through the entire system. Driving the kids to the local primary school is one kind of trip. Getting as far as Glasgow, under 15 miles away, makes a very different task — as does any miles on the M74, under a mile from Shawsburn, with the engine working hard the whole time.
Rattling, a ragged idle, smoke, a throttle gone soft: driven till it complained. That is your motor telling you its fuel has stopped behaving like diesel. Stop where you are — on the verge on Bannockburn Drive, at the kerb, down a side road — and don't move it again. The drain and flush still go first, and they take care of it: if a vehicle is pulled over early, long-term damage is very unusual.
What Shawsburn motorists 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. A bigger tank of the same mix is all you get, since topping up removes nothing. That advice presumes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. More precise components and higher pressure are how a current diesel runs its fuel, and that makes the lubrication count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools motorists. Feed diesel to a petrol motor and it generally won't run, so the driver stops — and the damage stops with them. A diesel fed petrol usually starts, idles and drives away as though nothing has happened, whilst the pump wears. A running engine does not mean fine.
Myth: "Add some two-stroke oil and drive it home." It is an outdated workaround for a separate problem. What petrol has thinned remains diluted, and the petrol remains in your tank regardless.
The next start sends petrol back round your pump from your lines and the fuel filter, where some of it ends up after the engine has been run. That is why a DIY tank drain does not sort it — a myth. Also, a can of petrol drained at the roadside is genuinely dangerous.
How does petrol in a diesel take place?
Nobody does it on purpose, and it's seldom carelessness. A diesel nozzle mostly will not go into a petrol car, but the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake straightforward, and just in one direction.
Routine and the vehicle getting out of step is how it takes place. A new car, a hire car or a courtesy car. One petrol and one diesel on the drive of the same household. A forecourt you know, but with its pumps laid out differently. Fuelling up in a rush on the way to Larkhall, with a train to catch. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Passat for the first time. Add rain, a phone call or a back seat full of children, and your hand repeats what it has always done.
Preventing petrol in a diesel next time you fill up around Shawsburn
- Check the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on each forecourt. The label is what matters.
- In a motor you don't know, look inside the flap over your filler or at the cap before the first fill: many cars state the fuel there.
- One of each in the household? Mark the key to the diesel — a bright fob, a sticker — since intending to remember is not enough.
- Before the nozzle comes off the pump the first time you fill a hired or new car, say "diesel" out loud. Silly, perhaps, but it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so put your phone away and keep your mind on the pump.
- Add-on devices are available for cars without one, and some diesels come with a filler that will not take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- The moment you notice, stop: less petrol inside the tank means a weaker mix. What to do next doesn't change, though — still don't start the vehicle.
Put petrol in a diesel around Shawsburn already?
Then the order of things is brief. Don't turn the ignition on, and do not crank it. If you're still at the forecourt — Shell or anywhere else — ask the staff to help you push it away from the petrol pump. Then ring 0333 366 0103 and tell us what got in, about how much, and if it has run.
Say so if it was AdBlue instead of petrol: it is a different issue, with its own page for Shawsburn, because AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel job around Shawsburn costs more than another. Why?
An honest single quote doesn't exist here: four situations, four separate jobs. Which of them you are in is mostly what shifts 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 questions come first, before any quote, instead of after — what was put in, how much, has it run — and that is the reason. Those answers are what change a range into one firm number.
About Shawsburn and its setting
Shawsburn is a riverside locality in South Lanarkshire, situated near the cities of Glasgow and the surrounding towns. Shawsburn sits at an elevation of 120 metres, close to nearby places such as Hareleeshill, Burnhead, and Machan. Shawsburn has a mix of housing types, with terraced housing being predominant in the area. Shawsburn is located approximately 14 miles from Glasgow, making it a commuter base for the city.
Fuel drain cover across South Lanarkshire, Shawsburn included
Petrol in diesel jobs in Shawsburn — part of the ML postcode area — go to vans that also cover the places around it, Hareleeshill, Burnhead and Machan included. The car doesn't need to come to us: we drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
In Shawsburn and still at the petrol pump?
Nothing beats it: that is where you are. Turned off it stays; then phone.