Weir: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less worried than you probably feel. Everyone in Weir starts with "have I wrecked it?", and the honest answer is usually no: petrol left inside the tank of a diesel stays harmless until priming, cranking or driving pulls it into the fuel system. Keep it that way: leave the engine off and ring Petrol in Diesel. What petrol really does to a diesel, how to gauge how far it's gone, and how to stop it from happening a second time: that's the rest of this page.
Inside your engine: what petrol in a diesel does
Passing through a motor, diesel does two jobs at once. It protects to begin with, and after that does it burn. Extremely fine gaps are built into the fuel injectors and the high-pressure pump, and only the diesel running through stops those surfaces grinding together.
Petrol does the first job poorly and the second not at all. A pump working on a petrol blend is wearing itself out, since petrol is runnier than diesel and takes away the lubrication your fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that's where any rattling starts.
The shape of the issue is clear when you put those together. It is movement that does the harm, not contact. Where that petrol is only inside the tank, it's an issue of fuel, nothing more. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the injectors further on.
How serious is petrol in a diesel? Four situations our technicians see around Weir
Fuelled but not once started — as good as it gets. The petrol is inside your tank and just the tank, and the job is a drain and a flush where your car stands. This is the one situation that can only really happen at a forecourt, since anywhere else your car has been driven to get there.
A brief spell of running, or merely the ignition on. Petrol has left the tank and got to the filter and the fuel lines, because the system has been primed. That is usually still a simple job — a drain, a flush, and the filter dealt with.
Driven a few miles. Now your pump has spent these miles labouring on thinned fuel. Mileage is only half of that; how hard it was driven counts equally. Either way this work runs to that tank, the fuel lines, the fuel filter and clean fuel through the whole system. On the school run to Northern Primary School, the miles is short. Very different once more: a trip to Manchester, under 25 miles away, or any mileage on the M65, under 10 miles from Weir, where the motor kept labouring hard.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone uneven. The fuel isn't behaving like diesel any more, and the motor is saying so. Stop wherever you are — the verge on Wesley Terrace, a lay-by, a side street — and leave it there. Long-term damage is very unusual if a car is pulled over soon, and the drain and flush that still come first take care of it.
Weir people and that petrol in a diesel myths they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing comes out when you top up — that tank just holds more of the same mixture. That advice supposes a diesel fuel system handles petrol by percentage. It does not.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." Lubrication matters more on newer diesels, not less, because their fuel runs through more precise components at higher pressure.
Myth: "If it starts and drives, there's no damage done." This is the one that catches drivers. Feed diesel to a petrol motor and it generally won't run, so the motorist stops — and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump grinds. Being able to run is not proof of being fine.
Myth: "Add some two-stroke oil and drive the car home." It's an outdated fix for a distinct fault. That petrol is still inside the tank after that, and whatever it has weakened isn't put back.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol lies in your filter and lines, ready to go right back through your pump on the next start. Emptying petrol into a can at the kerbside is also genuinely hazardous.
Why petrol in a diesel takes place at all
It's rarely carelessness, and nobody does it on purpose. A diesel nozzle mostly will not fit a petrol car, yet the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and only in that direction.
When habit and the vehicle stop matching, it happens. A new vehicle, a hire car or a courtesy car. Two vehicles on one driveway, one petrol, one diesel. The pumps in a different order on a familiar forecourt. Rushing for a train at Todmorden and fuelling up en route. Exactly the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. With rain, a call arriving, or children to deal with, your hand just does what it always has.
Weir motorists: how to avoid petrol in a diesel next time
- Green for unleaded and black for diesel is usual in the UK — but not on every forecourt. Go by the label on the petrol pump, not the colour.
- In a car you don't know, look inside the flap over your filler or at the cap before your first fill: many vehicles print the fuel there.
- A coloured fob or a sticker on the diesel's key does more than any amount of intending to remember, in a household with one of each.
- "Diesel", out loud, before you lift the nozzle — every time a new or hired car needs its first tank. It seems daft. It works.
- Thinking about something else is when this becomes an easy mistake to make, so tuck your phone away and keep your mind on the pump.
- Add-on devices are available for motors without one, and some diesels are built with a filler that won't take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Spotting it mid-fill? Stop there and then. A weaker mixture results from less petrol in your tank, but the next step remains the same: don't crank it.
Put petrol in a diesel in Weir already?
Then the order of things is short. Do not turn the ignition on, and do not start it. If you're still on the forecourt — Texaco or anywhere else — ask the attendants to help you roll the car clear of the petrol pump. Phone 0333 366 0103 next, with three answers — the fuel, the approximate quantity, and if it has run.
Say so if it was AdBlue instead of petrol: it's a different fault, with its own page for Weir, since AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel job in Weir costs more than another. Why?
Four separate tasks sit behind the four scenarios above — which is why there's no honest single price. Chiefly, the cost moves with which one you are in. Next it's the share — how much petrol got in against how much that tank holds — and after that where your car is and whether our van can get to it safely.
What got in, how much, and if it's run — three questions our engineers ask before pricing, not after, for exactly that reason. Their replies are what turn a range into one firm number.
About Weir, briefly
Weir is a village in Lancashire, situated on the riverside in the North West of England, with a population of around 1290 people. Weir sits at an elevation of 281 metres, surrounded by nearby places such as Higher Broad Clough, Broad Clough, and Sharneyford. Weir has a predominance of detached housing, reflecting its rural character. Weir is located 17.2 miles from Manchester and 176.2 miles from London.
Across Lancashire and around Weir: fuel drain cover
Our vans answering petrol in diesel jobs around Weir, in the OL postcode area, also work the locations around it, Higher Broad Clough, Broad Clough and Sharneyford among them. You need not bring the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
At the pump in Weir, right now?
Then you are in the best place there is. Keep it off. Ring.