How Worried Should You Be? Petrol in a Diesel Car in Cliff
Not started? Then less anxious than you probably feel. Petrol sitting in a diesel tank does nothing to your engine till something pulls it through the fuel system — your ignition priming your pump, the starter, or the drive itself. So the fair answer to the first query everyone around Cliff asks, "have I ruined it?", is normally no. Keep it like that: leave your motor off and phone Petrol in Diesel. Further down, you will find what petrol actually does inside a diesel, how far it might have got, and how to stop it happening to you again.
Your engine and petrol in a diesel: what goes on
On its way through an engine, diesel has two jobs. It burns, and before it combusts it lubricates. The high-pressure fuel pump and your injectors are built to very fine clearances, and your diesel passing through them is what stops those surfaces from wearing against one another.
Of those two jobs, petrol manages the first badly and the second not at all. It's thinner than diesel and strips away the lubrication the system depends 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 opposite of what a diesel needs from its fuel. That's where the clattering comes from.
Taken together, they show what shape the issue has. It is movement that causes the damage, not contact. Where the petrol is only inside the tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds goes on, borne by the fuel, into the injectors downstream, which is why a pump that has been working on that petrol is where a mechanical fault begins.
Cliff, petrol in a diesel: four situations, from mild to serious
The best case there can be: filled up, not once started. Just the tank has petrol in it, so the task is emptying that tank and cleaning the fuel system where the vehicle sits. This situation can only truly take place at a forecourt: anywhere else, your car got there by being driven.
Your ignition switched on, or a short start. With your system primed, your lines and filter now contain petrol that came from your tank. Drain, flush, see to the filter: still normally simple.
Your pump now spent a few miles on diluted fuel — that's what driving the car does. The work is your tank, the fuel lines, the filter and fresh fuel through the entire circuit, and how hard the vehicle was driven matters as much as how far. Driving the children to Holmfirth Junior Infant and Nursery School is one sort of trip. Any distance on the Outlane Interchange, under 10 miles from Cliff, means your engine working hard throughout, and a run to Wakefield, under 15 miles away, makes a very different job as well.
Knocking, a ragged idle, smoke, a throttle gone soft: driven until it complained. The motor is telling you the fuel is no longer acting like diesel. Stop wherever you are — the verge on Cliffe Street, a lay-by, a side street — and leave the car where it is. The fuel drain and flush-through still come first, and they sort it out: when a vehicle is pulled over early, permanent damage is very uncommon.
Cliff drivers and that petrol in a diesel myths they hear
False: topping up to full with diesel makes it fine. It does not. Nothing is removed when you top up — that tank simply carries more of the same blend. The idea behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the reverse. More precise parts and higher pressure are how a current diesel runs its fuel, and that makes the protection count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools motorists. Diesel in a petrol motor usually means a motor that will not run: the motorist stops, and so does the damage. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump wears. A running engine does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different issue. None of what petrol weakened gets put back by it — and afterwards, that tank still contains the petrol.
Myth: "Drain your tank yourself and you're sorted." Once your engine has been run, some of that petrol is no longer inside your tank: it's in the filter and the fuel lines, and it goes right back through your pump on your next start. It's also genuinely hazardous to drain petrol into a can by the kerbside.
Why petrol in a diesel takes place so easily
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle mostly will not fit a petrol car, yet the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and only in one direction.
It occurs when routine and the car stop matching. A motor that's new to you — hired, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Rushing for a train outside Brockholes and filling up en route. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it occurs. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
Cliff drivers: how to avoid petrol in a diesel next time
- A green handle for unleaded and black for diesel is usual in the UK — yet not on each forecourt. Go by the label on the petrol pump, not the colour.
- In a motor you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of vehicles print the fuel type there.
- Good intentions do less than a sticker or a fob in a bright colour on the diesel's key when a house has one of each. So mark it.
- It seems daft and it does the trick: on the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump.
- Tuck the phone away. This is an easy mistake to make whilst you are thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop reading the petrol pump.
- Noticing it mid-fill? Stop at once. A weaker mixture follows from less petrol in your tank, yet your next stage stays the same: don't fire it up.
Put petrol in a diesel in Cliff already?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition switched off as well. Ask the staff to help you roll it clear of the petrol pump if you are still on the forecourt, whether that's Murco or somewhere else. What went in, roughly how much, and whether it's run: tell us that when you phone 0333 366 0103.
Corrosion and deposits form the issue with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and read its own Cliff page.
One petrol in a diesel job in Cliff costs more than another. Why?
There is no honest single price for this, because the four scenarios above are four different jobs. What shifts your cost is mostly which of them you are in. The share matters next, meaning how much of the tank is petrol, and then the position of the vehicle and whether getting to it is safe for a van.
What was put in, how much, and whether it has run — three queries we ask before quoting, not after, for precisely that reason. Given those replies, there is a straight figure instead of a range.
About Cliff
Cliff is a suburban area situated on the riverside in West Yorkshire, with a mix of terraced housing and a population of around 1642 residents. Cliff sits at an elevation of 218 metres, providing views of the surrounding landscape. Cliff is located near several other suburban areas, including New Town and New Gate, and is within commuting distance of Wakefield, which is approximately 13.9 miles away. Cliff is also relatively close to the town of Holmfirth, which offers additional amenities and services.
Fuel drain cover in Cliff and across West Yorkshire
Cliff sits in the HD postcode area, and the vans that answer petrol in diesel jobs there work the places near it as well — New Town, New Gate and Holmfirth among them. The vehicle does not need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Cliff: still at the petrol pump?
In that case, you could not be in a better place. Leave it turned off, and ring.