Sharrow Vale: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less worried than you likely feel. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through the fuel system — your ignition priming the pump, the starter, or driving on its own. So the fair answer to the first question everyone around Sharrow Vale asks, "have I ruined it?", is generally no. Leave the motor off and phone Petrol in Diesel — that keeps it like that. The remainder of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
Petrol in a diesel: what does it do to your engine?
Passing through a motor, diesel is doing two jobs at once. Before it combusts, it lubricates — and then it combusts. Your high-pressure pump and your injectors are built to very fine clearances, and your diesel passing through them is what stops those surfaces from wearing down against one another.
The second task petrol does not do at all, and the first it does badly. A pump working on a petrol mix is wearing itself out, because petrol is runnier than diesel and takes away the protection the fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that is where the knocking comes.
The shape of the trouble is clear once you put those together. It's circulation that does the harm, not contact. Any tank with petrol in it is a fuel fault. Whatever a worn pump sheds travels on, carried by your fuel, into the injectors downstream, which is why a pump that has been working on the petrol is where a mechanical issue starts.
Four scenarios our engineers see around Sharrow Vale: how serious is petrol in a diesel?
Filled up, not once started. The best case there is. On a forecourt, and really only there, the petrol is still confined to the tank — since everywhere else the vehicle was driven to reach it. The job is draining and rinsing on the spot.
A brief spell of running, or merely your ignition on. Petrol has come out of the tank and reached the filter and your lines, since the system has been primed. Still usually simple: drain, flush, and your filter sorted.
A couple of miles driven, and your pump has spent each of them working on weakened fuel. How hard the car was driven counts as much as how far, and the work takes in your tank, the fuel lines, the fuel filter and fresh fuel through the whole system. On the school run to Hunter's Bar Junior School, the miles is short. A run as far as Sheffield, under 3 miles away, is a very different task. So is any distance on the M1, under 10 miles from Sharrow Vale, where your engine has been working hard the whole time.
Driven till it protested. Knocking, a lumpy idle, smoke, a throttle that has gone soft. That's your motor telling you its fuel has stopped behaving like diesel. Pull up on the spot — on the verge on Sharrow Vale Road, at the kerb, down a side road — and don't move it. Lasting damage is very uncommon if a vehicle is stopped soon, and the drain and flush that still go first take care of it.
Petrol in a diesel myths Sharrow Vale drivers hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing comes out when you top up — your tank simply holds more of the same blend. A diesel fuel system does not accept petrol by percentage in the way that advice assumes.
Not so: a current diesel copes with a bit of petrol. Rather, the reverse. More precise parts and higher pressure are the way a newer diesel runs its fuel, and that makes the lubrication matter more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there's no harm done." The motorist of a petrol engine fed diesel normally stops, because it will not run, and the harm stops with them. Whilst the pump grinds, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. Being able to run isn't the same as being fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate fault. It does not put back what petrol has weakened, and the petrol is still in your tank later on.
If your engine has been run, part of the petrol sits in the filter and your lines, not your tank — and your next start pulls it straight back through your pump. So the myth "drain your tank yourself and you're sorted" doesn't hold. Emptying petrol into a can at the roadside is also really risky.
Why petrol in a diesel takes place at all
Carelessness is seldom the cause, and no one means to do it. The petrol nozzle is the smaller of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol car at all. The forecourt makes it easy, and the mistake runs one way.
Habit and the vehicle getting out of step is when it takes place. Hire cars, courtesy cars, and cars that are new to you. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. A rushed fill on the way to Sheffield with a train to catch. Years of petrol motors behind you, a diesel Renault Clio in front of you at the forecourt for its first tank — that is when. Add a back seat full of kids, a phone call or rain, and habit wins.
How to avoid petrol in a diesel on your next fill-up around Sharrow Vale
- Check the pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on every forecourt. The label is what counts.
- The first fill in a strange car is the time to check your filler flap — inside it, or on the cap, plenty of motors state which fuel they take.
- One of each in the house? Label your key to your diesel — a coloured fob, a sticker — because meaning to remember isn't enough.
- It seems silly and it works: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- Mistakes like this are straightforward to make while your mind is on something else, and so the phone goes away.
- Add-on devices are available for motors without one, and some diesels come with a filler that will not take a petrol nozzle. Helpful — but a backstop only, never a reason to stop checking the label.
- Spotting it halfway? Stop there and then. A weaker mixture follows from less petrol inside the tank, yet the next step remains the same: do not fire it up.
Petrol already in a diesel in Sharrow Vale? Begin here
Then the order of things is short. Starting it is out, and so is turning on your ignition. Still at the forecourt, at Esso or anywhere else? Ask the attendants to help you roll it away from the pump. Call 0333 366 0103 next, with three answers — the fuel, the rough volume, and whether it has run.
Corrosion and deposits form the problem with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and read its own Sharrow Vale page.
One petrol in a diesel job in Sharrow Vale costs more than another. Why?
A fair single price doesn't exist here: four situations, four separate tasks. Which of them you are in is chiefly what shifts your cost. Where the car is counts too, and whether a technician can safely get to it, after the ratio of petrol to what the tank takes.
Three questions come first, before quoting, instead of after — what was put in, how much, has it run — and that is the reason. A range becomes a straight figure when those replies are in.
About Sharrow Vale, for a moment
Sharrow Vale is a suburban area located on the riverside in South Yorkshire, sitting at an elevation of 99 metres and approximately 1.6 miles from Sheffield city centre. Sharrow Vale is characterized by its predominantly terraced housing stock, reflecting the area's historical development. Sharrow Vale forms part of the larger Sheffield urban area, with nearby places including Sharrow Head, Brincliffe, and Endcliffe Crescent. Sharrow Vale is home to a population of around 10489 residents.
Sharrow Vale and South Yorkshire: where our fuel drain cover runs
Petrol in diesel calls around Sharrow Vale — part of the S postcode area — go to vans that also cover the locations round it, Sharrow Head, Brincliffe and Endcliffe Crescent among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians drain, and the car doesn't need to move to us.
Sharrow Vale: still at the petrol pump?
The best place there is, then — that is where you are. Switched off it remains; then phone.