Wadcroft: Petrol in a Diesel Car? How Worried to Be
Probably less than you are now — as long as nobody has started the car. Everyone around Wadcroft starts with "have I wrecked it?", and the honest answer is generally no: petrol resting inside your tank of a diesel stays harmless until priming, cranking or driving draws it into the fuel system. Keep it that way: leave the engine off then phone Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and ways to make sure you don't do it again.
The motor and petrol in a diesel: what goes on
Passing through a motor, diesel does two jobs at once. Before it ignites, it protects — and then it burns. What stops the surfaces inside the high-pressure pump and the injectors from grinding against each other is the diesel passing through them — they're built to extremely fine tolerances.
Badly at the first, not at all at the second: that's petrol. It's runnier than diesel and strips away the lubrication your fuel system rests 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 is where the rattling comes from.
Put those together and the shape of the trouble is plain. Not contact but movement is what causes the harm. Petrol in a tank is a fuel fault. The beginning of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with the fuel to the injectors downstream.
How serious is petrol in a diesel? Four situations our engineers see in Wadcroft
Fuelled up, never started. The best case there is. On a forecourt, and truly only there, the petrol is still confined to your tank — since anywhere else the car was driven to get to it. The job is emptying and rinsing on the spot.
Ignition on, or started for a moment. Petrol has come out of that tank and got to the fuel filter and your lines, because the system has been primed. That is normally still a simple job — a drain, a flush, and your filter seen to.
Those few miles on the road were the pump working on fuel weakened by petrol the whole way. The work is your tank, the lines, your filter and clean fuel through the whole circuit, and how hard the vehicle was driven counts as much as how far. Driving the kids to St Thomas More Catholic Primary School is one kind of trip. A run as far as Leicester, under 25 miles away, is a very different task. So is any miles on the M1, under 25 miles from Wadcroft, where your engine has been working hard throughout.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven till it complained. The fuel is not behaving like diesel any more, and your motor is saying so. Whether it is the verge on Bellfoundry Lane, a lay-by or a side street, stop where you are and leave it. A car stopped early very rarely has permanent damage, since the drain and the flush, which still come first, take care of it.
Petrol in a diesel stories Wadcroft drivers 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 — your tank simply carries more of the same blend. That advice supposes a diesel fuel system tolerates petrol by percentage. It doesn't.
If anything, the reverse is true. Myth: "A current diesel can cope with a bit of petrol." Lubrication counts more on modern diesels, not less, because their fuel passes through finer components at higher pressure.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it normally will not run, so the motorist stops — and the harm stops with them. Feed petrol to a diesel and it generally starts, ticks over and drives away like nothing has happened — all while its pump wears. Being able to run is not the same as being fine.
An outdated fix for a distinct fault lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." It doesn't put back what petrol has thinned, and that petrol is still inside your tank later on.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol lies in the filter and lines, waiting to go straight back through the pump on the next start. Besides, petrol drained into a can by the road is genuinely risky.
How it happens: petrol in a diesel
It is rarely carelessness, and nobody does it on purpose. A diesel nozzle generally won't fit a petrol vehicle, but the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake easy, and only in that direction.
The moment routine stops matching the car is the moment it takes place. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Racing for a train outside Kettering and filling up en route. Years of petrol vehicles behind you, a diesel Renault Megane 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 takes over.
Wadcroft drivers: how to prevent petrol in a diesel next time
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most usually do. Check the pump's label; the colour is just a clue.
- The first fill in a new car is the time to check the filler flap — on it, or on the cap, many vehicles state which fuel to use.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, for a household with one of each.
- Before the nozzle comes off the petrol pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Silly, yes, but it works.
- Whilst you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop checking the pump.
- Less petrol means a thinner mixture, and so stop as soon as you realise — though remembering that the next stage is unchanged. It is still not to start it.
Petrol already in a diesel in Wadcroft? Begin here
In that case, there is only a short order of things. Never fire it up, and do not switch the ignition on. If you're still at the forecourt — Texaco or anywhere else — ask the attendants to help you push it clear of the petrol pump. Ring 0333 366 0103 next, with three answers — the fuel, the rough quantity, and if it's run.
Corrosion and deposits are the issue with AdBlue, whereas petrol brings lost lubrication. So if it was AdBlue, say so — and read its own Wadcroft page.
What makes one Wadcroft petrol in a diesel job cost more than the next
There is no fair single quote for this, because the four scenarios above are four different tasks. What moves your cost is chiefly which of them you're in. Where the car is counts too, and whether a van can safely get to it, after the proportion of petrol to what the tank takes.
Three queries come first, before any quote, instead of after — what got in, how much, has it run — and that is the reason. Those replies are what turn a range into one firm number.
About Wadcroft, for a moment
Wadcroft is a suburban area situated on the riverside in Northamptonshire, with a mix of terraced housing and other residential properties. Wadcroft sits at an elevation of around 90 metres, close to the towns of Kettering and the villages of Thorpe Malsor and Weekley. Wadcroft is located near the city of Leicester, which is approximately 23.5 miles away, and is also within commuting distance of London, around 66.7 miles to the south. Wadcroft has a population of around 7850 people, making it a moderately sized suburban community.
Fuel drain cover across Northamptonshire, Wadcroft included
Petrol in diesel call-outs around Wadcroft — part of the NN postcode area — go to teams that also cover the spots around it, Kettering, Thorpe Malsor and Weekley among them. Our technicians drain wherever your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
In Wadcroft and still at the pump?
Nothing beats it: that is where you now are. Keep it off. Phone.