How Worried Should You Be? Petrol in a Diesel Car in Southery
If it hasn't been started, you can worry less than you likely are. "Have I wrecked it?" is the first question anyone in Southery asks, and the truthful answer is generally no, because petrol resting in a diesel tank harms nothing until it's dragged through the system — by ignition priming, by the starter, or by being driven. Petrol in Diesel is who to call, with the motor kept off, so it stays that way. The rest of this page explains what petrol really does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
What petrol in a diesel does to the motor
Diesel does two jobs on its way through a motor. Lubricating comes before burning; it does both. Very fine clearances go into your injectors and the high-pressure fuel pump, and only your diesel running through keeps their surfaces from grinding together.
Of these two tasks, petrol handles the first poorly and the second not at all. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the system rests on, and any pump running on that blend is wearing itself.
Together, those leave the shape of the issue plain. Not contact but movement is what causes the harm. Where the petrol is only in that tank, it's an issue of fuel, nothing more. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the injectors downstream.
How serious is petrol in a diesel? Four scenarios our technicians see around Southery
Filled up, and not started: nothing beats it. The petrol is in your tank and only your tank, and the job is a drain and a flush where the car stands. This is the one scenario that can only really take place on a forecourt, because anywhere else your car has been driven to get there.
A moment's running, or merely your ignition on. Petrol has left the tank and got to the filter and the fuel lines, because the system has been bled. Still generally easy: drain, flush, and the fuel filter seen to.
Driven a few miles. Now your pump has spent these miles running on diluted fuel. Mileage is only half of that; how hard it was driven matters equally. Either way the work runs to the tank, the lines, the fuel filter and fresh fuel through the entire circuit. Driving the kids to Southery Academy is one sort of trip. Any mileage on the M11, under 25 miles from Southery, means your engine working hard throughout, and a run to Ely, under 15 miles away, makes a very different job as well.
Driven on till it protested — rattling, smoke, an uneven idle, a dead throttle. The fuel is not behaving like diesel any more, and your motor is saying so. Whether it's the verge on Upgate Street, a lay-by or a side street, stop there and leave it. The drain and flush-through still go first, and they sort it out: if a car is stopped quickly, permanent damage is very unusual.
Myths Southery drivers hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Topping up removes nothing; it gives you a bigger tank of the same mix. A diesel fuel system does not tolerate petrol by percentage in the way that advice supposes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. Lubrication counts more on current diesels, not less, since their fuel runs through more precise components at higher pressure.
Myth: "If it starts and drives, there is no harm done." This is the one that catches motorists. Feed diesel to a petrol motor and it usually won't run, so the driver stops — and the harm stops with them. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, while the pump wears. Running isn't the same as fine.
Myth: "Add some two-stroke oil and drive the car home." It is an outdated fix for a separate fault. What petrol has weakened remains thinned, and that petrol stays inside the tank anyway.
The next start sends petrol back round your pump out of the lines and your filter, where some of it ends up after your engine has been run. That's why a DIY tank drain doesn't sort it — a myth. It is also genuinely risky to drain petrol into a can at the roadside.
How does petrol in a diesel take place?
It is 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, whilst a diesel nozzle mostly will not go into a petrol car at all. So the mistake runs one way.
The moment routine stops matching the vehicle is the moment it occurs. Courtesy car, hire car, or a motor that is brand new. Two vehicles on one drive, one petrol, one diesel. A forecourt you know, but with its pumps arranged differently. Fuelling up in a rush en route to Littleport, with a train to catch. Precisely the moment it occurs: after years of driving petrol, someone fills a diesel Volkswagen Tiguan for the first time. Add a back seat full of children, a phone call or rain, and the hand wins.
Preventing petrol in a diesel next time you fill up around Southery
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Read the pump's label; the colour is only a hint.
- Check your filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on your first fill in a car you do not know.
- Good intentions do less than a sticker or a fob in a bright colour on the diesel's key when a household has one of each. So label it.
- It seems daft and it does the trick: on the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump.
- Tuck your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Add-on devices are available for cars without one, and some diesels are built with a filler that will not accept a petrol nozzle. Helpful — but a backstop at best, never a reason to stop checking the label.
- Noticing it mid-fill? Stop there and then. A weaker mixture follows from less petrol in the tank, yet the next step stays the same: don't crank it.
Petrol already in a diesel around Southery? Start here
In that case, there is just a short order of things. Do not turn the ignition on, and don't fire it up. If you're still on the forecourt — Esso or anywhere else — ask the staff to help you roll the vehicle away from the pump. Phone 0333 366 0103 next, with three answers — your fuel, the rough volume, and if it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different issue — Southery has a page all for it.
What makes one Southery petrol in a diesel job cost more than the next
There's no honest single price for this, because the four situations above are four separate jobs. What moves your cost is chiefly which of them you are in. Two things follow that: the petrol that got in as a share of what your tank holds, then the place the car is in and whether a technician can reach it safely.
Three questions come first, before any quote, rather than after — what was put in, how much, has it run — and this is the reason. With those replies, there is a straight figure rather than a range.
About Southery
Southery is a small village in Norfolk, situated in the inland area of the Fens, with an elevation of around 13 metres. Southery lies near the villages of Little London and Ten Mile Bank, and is close to the River Great Ouse. Southery has a population of approximately 1258 people, living in predominantly detached housing. Southery is located near the city of Ely, which is about 10 miles away.
Southery and Norfolk: where our fuel drain cover runs
The teams answering petrol in diesel call-outs around Southery, in the PE postcode area, equally work the places around it, Little London, Ten Mile Bank and Brandon Creek included. The car does not need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Southery and still at the petrol pump?
Then you're in the best position there can be. Leave the vehicle turned off, then ring.