Stansty: Petrol in a Diesel Car? How Worried to Be
Probably less than you are now — as long as no one has started the vehicle. Everyone around Stansty starts with "have I ruined it?", and the fair answer is generally no: petrol resting in that tank of any diesel remains harmless until priming, cranking or driving draws it into the system. To leave the car that way, ring Petrol in Diesel then leave the engine switched off. The rest of this page covers what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
The motor and petrol in a diesel: what happens
Two tasks fall to diesel on its route round a motor. It protects first, and after that does it burn. Very fine tolerances are built into your injectors and the high-pressure pump, and only your diesel flowing through stops their surfaces grinding together.
Badly at the first, not at all at the second: that is petrol. The rattling comes from petrol being designed not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection the fuel system hinges on, and any pump working on that blend is wearing itself.
Seen together, they make clear what shape the problem has. The damage is done by circulation, not by contact. A tank with petrol in it is a fuel problem. The beginning of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Petrol in a diesel in Stansty: how bad is it? Four situations
Filled up, never started. The best case there is. Just the tank has petrol in it, and so the task is clearing that tank and flushing your system where the vehicle sits. This scenario can only truly occur at a forecourt: anywhere else, the car got there by being driven.
The ignition switched on, or a brief start. With the fuel system primed, your lines and filter now contain petrol that came from that tank. That's usually still an easy job — a drain, a flush, and your filter dealt with.
Driven a few miles. Now the pump has spent these miles working on thinned fuel. Distance is only half of it; how hard it was driven matters just as much. Either way this work runs to that tank, the fuel lines, the fuel filter and fresh fuel through the entire system. A school run to the local primary school is one thing. Any distance on the M53, under 15 miles from Stansty, means your engine has worked hard throughout, and a run to Wrexham, under a mile away, makes a very different task as well.
Driven until it protested. Rattling, a lumpy idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer behaving like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Weston Drive. What goes first is still the fuel drain and flush-through, and that deals with it, with long-term damage very unusual if a car is pulled over quickly.
What Stansty people get told about petrol in a diesel — and the myths in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Topping up removes nothing; it gives you a fuller tank of the same mixture. That advice assumes a diesel fuel system handles petrol by percentage. It doesn't.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. Protection counts more on modern diesels, not less, because their fuel runs through finer parts at higher pressure.
This is the one that fools motorists. Myth: "If it starts and drives, there's no harm done." Diesel in a petrol motor generally leaves a motor that won't run: the driver stops, and so does the damage. Feed petrol to a diesel and it normally fires up, idles and pulls away as if nothing has happened — all the while its pump wears. Running isn't the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, meant for another fault. None of what petrol thinned gets put back by it — and afterwards, that tank still holds the petrol.
Myth: "Drain your tank yourself and you are sorted." Once the engine has been run, some of the petrol is no longer inside that tank: it is in the fuel filter and the fuel lines, and it goes right back through the pump at your next start. It is also really dangerous to drain petrol into a can at the roadside.
How it happens: petrol in a diesel
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol vehicle at all. The forecourt makes it easy, and the mistake runs one way.
Routine and the vehicle getting out of step is when it occurs. Courtesy car, hire car, or a vehicle that's brand new. One petrol and one diesel on the driveway of the same household. Your usual forecourt, its pumps suddenly in a different order. Racing for a train outside Wrexham General and fuelling up en route. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. Throw in a back seat full of kids, a phone call or rain, and habit wins.
Stansty people: how to avoid petrol in a diesel next time
- A green handle for unleaded and black for diesel is normal in the UK — yet not on every 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, and so check it on your first fill in any vehicle you do not know.
- Mark the key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- It sounds silly and it works: on your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- While 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 have a filler built to block a petrol nozzle, and aftermarket devices are available for the remainder. Count it as a safety net, then keep checking the pump.
- Stop the moment you notice. Less petrol in that tank means a thinner mix. It does not change what to do next, which is still not to fire it up.
Petrol already in a diesel in Stansty? Start here
Then the order of things is short. Don't crank it, and don't turn your ignition on. If you are still on the forecourt — Sainsbury's or anywhere else — ask the attendants to help you roll it away from the pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it has been run.
Corrosion and deposits are the issue with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and read its own Stansty page.
Stansty petrol in a diesel tasks: why one costs more than another
The four situations above are four separate jobs, so no single quote for this would be fair. The situation itself does most of the work of moving your cost. Where your car is counts too, and whether a technician can safely get to it, after the proportion of petrol to what your tank holds.
That is why our engineers ask three queries before quoting rather than after: what got in, how much, and whether it's run. Those answers turn a range into a straight figure.
About Stansty itself
Stansty is a suburban area located on the outskirts of Wrexham in north-east Wales, sitting at an elevation of 87 metres above sea level. Stansty is characterized by its predominantly semi-detached housing stock and is situated close to nearby places such as Plas Coch and Rhosddu. Stansty has a population of approximately 3569 residents and is within walking distance of Wrexham town centre. Stansty is also near Croes Eneurys, another local suburb.
Fuel drain cover in Stansty and across Wrexham
Petrol in diesel jobs around Stansty — part of the LL postcode area — go to vans that likewise cover the spots round it, Plas Coch, Croes Eneurys and Rhosddu included. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians work, and your vehicle doesn't need to come to us.
In Stansty and still at the pump?
No position is better: that is where you are. Call, and leave it turned off.