Craighall: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — provided no one has started the vehicle. Petrol sitting in a diesel tank does nothing to the engine until something draws it through your fuel system — the ignition priming your pump, the starter, or driving itself. So the truthful answer to the first query anyone around Craighall asks, "have I ruined it?", is usually no. Petrol in Diesel is who to call, with your motor left off, and so it stays that way. What petrol actually does to a diesel, how to judge how far it's gone, and how to stop it from happening a second time: that is the remainder of this page.
Petrol in a diesel: what does it do to the engine?
On its way through a motor, diesel has two tasks. It protects to begin with, and only then does it burn. Made to very fine tolerances, the injectors and the pump depend on your diesel moving through them to stop their surfaces wearing against one another.
The second job petrol does not do at all, and the first it does badly. The clattering comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection the system hinges on, and any pump working on such a mixture is wearing itself.
The shape of the trouble is plain once you put those together. The damage is done by movement, not by contact. Petrol in the tank is a fuel issue. After the pump has been working on that petrol, a mechanical problem has started: whatever is shed by a pump that is grinding travels onward to your injectors with your fuel.
Four scenarios our engineers see in Craighall: how bad is petrol in a diesel?
Filled but never started — the best it gets. On a forecourt, and really only there, the petrol is still limited to your tank — since anywhere else the vehicle was driven to reach it. The job is draining and purging on the spot.
The ignition switched on, or a brief start. Petrol has left that tank and got to your filter and the lines, because the fuel system has been primed. Normally little more than draining, flushing and sorting the fuel filter, so still easy.
Those few miles driven meant the pump working on fuel diluted by petrol the whole way. The work is that tank, the fuel lines, your filter and fresh fuel through the whole circuit, and how hard your car was driven matters as much as how far. Driving the children to the local primary school is one kind of trip. Any miles on the M90, over 50 miles from Craighall, means the engine has worked hard throughout, and a run to Aberdeen, under 15 miles away, makes a very different job as well.
Driven till it protested. Knocking, a lumpy idle, smoke, a throttle that has gone soft. What you are hearing is the motor reporting fuel that no longer behaves like diesel. Leave it where it has stopped: a lay-by, a side street, the verge on St Mary's Drive. What comes first is still the fuel drain and flush, and that deals with it, with long-term damage very unusual if a car is stopped early.
Craighall drivers and the petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing comes out when you top up — that tank simply holds more of the same blend. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance supposes.
Myth: a modern diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through smaller parts: that's how a current diesel handles its fuel, so the lubrication counts more, not less.
One myth that catches drivers off guard: if it starts and drives, it must be unharmed. A petrol motor fed diesel usually will not run, and so the motorist stops and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump grinds. Running is not the same as fine.
An outdated fix for a different issue is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has diluted remains diluted, and that petrol stays in your tank regardless.
The next start sends petrol back round your pump from your lines and the fuel filter, where some of that sits after your engine has run. That's why draining your tank yourself doesn't sort it — a myth. On top of that, petrol emptied into a can by the road is genuinely dangerous.
Petrol in a diesel: how does it take place?
No one does it on purpose, and it is seldom carelessness. A diesel nozzle mostly won't go into a petrol car, yet the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error straightforward, and just in that direction.
The moment routine stops matching the vehicle is the moment it takes place. Hire cars, courtesy cars, and vehicles that are new to you. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps laid out differently. A train to catch, and a hurried fill on the way to Dyce. Precisely the moment it happens: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. Throw in rain, a phone call or a back seat full of children, and your hand does what it has always done.
How to prevent petrol in a diesel on your next fill-up around Craighall
- A green handle for unleaded and black for diesel is usual in the UK — yet not on each forecourt. Trust the label on the petrol pump, not the colour.
- Many cars state the fuel type inside your filler flap or on the cap, so check it on the first fill in any motor you don't know.
- One of each in the home? Label the key to your diesel — a bright fob, a sticker — since meaning to remember isn't enough.
- Before the nozzle leaves the petrol pump the first time you fuel a hired or new car, say "diesel" aloud. Daft, perhaps, but it works.
- Whilst you are thinking about something else, this is an easy mistake to make — so put the phone away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to block a petrol nozzle, and add-on devices exist for the rest. Treat it as a backstop, and keep checking the pump.
- Noticing it mid-fill? Stop at once. A thinner blend follows from less petrol inside your tank, yet your next stage remains the same: do not fire it up.
Put petrol in a diesel around Craighall already?
Then the order of things is short. Don't turn the ignition on, and do not start it. If you are still at the forecourt — Esso or anywhere else — ask the attendants to help you roll it away from the petrol pump. What got in, about how much, and if it has run: tell us that when you phone 0333 366 0103.
If it was AdBlue rather than petrol, say so. That's a different problem — corrosion and deposits and not lost lubrication — and it has its own page for Craighall.
What makes one Craighall petrol in a diesel job cost more than the next
There's no honest single price for this, since the four situations above are four different tasks. What moves the cost is chiefly which of them you're in. The ratio matters next, meaning how much of your tank is petrol, and then the position of your car and whether getting to it is safe for a technician.
What went in, how much, and if it's run — three questions our engineers ask before costing, not after, for exactly that reason. Those answers turn a range into a straight figure.
About Craighall, for a moment
Craighall is a suburban area situated on the riverside in Aberdeenshire, with an elevation of around 25 metres. Craighall lies near the towns of Ellon and Meiklemill, and is approximately 14.6 miles from Aberdeen. Craighall has a population of around 2118 people, predominantly living in semi-detached housing. Craighall is located in a scenic area, with the surrounding countryside offering opportunities for outdoor activities.
Across Aberdeenshire and around Craighall: fuel drain cover
The teams answering petrol in diesel calls around Craighall, in the AB postcode area, equally work the locations around it, Ellon, Meiklemill and Esslemont among them. A forecourt, a supermarket car park, a lay-by or your own drive are all locations we work, and the vehicle doesn't need to come to us.
Still at the pump around Craighall?
Nothing beats it: that is where you now are. Keep the vehicle switched off, and ring.