Blists Hill: Petrol in a Diesel Car? How Worried to Be
Less than you probably are, provided it hasn't been started. Everyone in Blists Hill begins with "have I wrecked it?", and the honest answer is normally no: petrol left in that tank of a diesel remains harmless till priming, cranking or driving draws it into the fuel system. Leave your engine off then call Petrol in Diesel — that is how you keep it like that. The remainder of this page covers what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
Inside your engine: what petrol in a diesel does
Passing through an engine, diesel does two things at once. Before it ignites, it protects — and then it burns. Made to extremely fine gaps, the fuel injectors and the pump depend on your diesel flowing through them to stop their surfaces wearing against one another.
Of those two jobs, petrol handles the first poorly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so a pump on the mixture wearing itself. It's equally made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the clattering.
Combined, those leave the shape of the trouble plain. The harm is done by circulation, not by contact. Petrol in a tank is a fuel fault. The start of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with the fuel to the fuel injectors beyond it.
How serious is petrol in a diesel? Four situations we see in Blists Hill
Fuelled, and not started: no case is better. Being on a forecourt is what makes this the case: elsewhere, your car has been driven there to begin with. With that petrol held in that tank alone, it's emptied and cleaned right where it stands, and nothing more is needed.
The ignition turned on, or a short start. The fuel system has been primed, so petrol has left your tank and got to your filter and the lines. Still generally straightforward: drain, flush, and the fuel filter dealt with.
A few miles driven, and your pump has spent each of them working on weakened fuel. Tank, lines, filter, then fresh fuel run through the whole system: that's the work, and the way the vehicle was driven matters as much as the distance. A school run to John Fletcher of Madeley Primary School is one matter. Getting as far as Wolverhampton, under 15 miles away, makes a very different job — as does any miles on the M54, under 5 miles from Blists Hill, with the motor labouring hard the whole time.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone uneven. That is the engine telling you its fuel has stopped acting like diesel. Pull up wherever you are — the verge on Coalport Road, a lay-by, a side street — then leave the vehicle there. What comes first is still the fuel drain and flush-through, and that sorts it out, with long-term damage very uncommon if a car is stopped quickly.
Blists Hill people and the petrol in a diesel stories they hear
False: topping up to full with diesel makes it fine. It does not. Nothing is removed when you top up — the tank just carries more of the same mixture. A diesel fuel system does not accept petrol by percentage in the way that guidance assumes.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. Protection matters more on modern diesels, not less, since their fuel passes through more precise components at higher pressure.
"It starts, it drives, and so there is no harm" — the myth that catches most motorists than any other. Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the damage. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump wears. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate fault. The petrol is still inside the tank after that, and what it has weakened is not put back.
Myth: "Drain your tank yourself and you are sorted." Once your engine has run, some of the petrol is no longer inside that tank: it is in the fuel filter and the fuel lines, and it goes straight back through your pump at the next start. It's also truly hazardous to drain petrol into a can at the roadside.
How does petrol in a diesel happen?
A careless moment is seldom the cause, and nobody means to do it. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one mostly will not fit a petrol motor. That's how the forecourt makes it straightforward.
It occurs when habit and your car stop matching. A vehicle that is new to you — a hire car, on loan as a courtesy car, or brand new. Two vehicles on one drive, one petrol, one diesel. A forecourt you know, but with its pumps laid out differently. Filling up in a rush en route to Telford Central, with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is precisely the moment it takes place. Throw in rain, a phone call or a back seat full of children, and the hand does what it has always done.
Blists Hill motorists: 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 every forecourt. Go by the label on the petrol pump, not the colour.
- Check your filler flap. Plenty of motors state the fuel inside the flap or on the cap. Look at it on the first fill in a motor you do not know.
- Mark the key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump. It sounds daft and it does the trick.
- Mistakes like this are simple to make while your mind is on something else, and so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to reject a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop checking the pump.
- Stop the moment you notice. Less petrol inside your tank makes a weaker mix. It doesn't change what to do next, which is still not to crank it.
Petrol already in a diesel in Blists Hill? Begin here
The order of things is short, then. Don't crank it, and do not switch your ignition on. If you are still at the forecourt — Esso or anywhere else — ask the staff to help you roll it clear of the petrol pump. Phone 0333 366 0103 next, with three answers — the fuel, the rough volume, and whether it has run.
Corrosion and deposits form the issue with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and read its own Blists Hill page.
One petrol in a diesel task around Blists Hill costs more than another. Why?
There's no fair single quote for this, because the four situations above are four different jobs. What shifts your cost is mostly which of them you're in. Where the car is counts too, and whether a van can safely get to it, after the share of petrol to what that tank holds.
That is why our technicians ask three queries before quoting rather than after: what was put in, how much, and if it's run. Those replies turn a range into a straight figure.
About Blists Hill
Blists Hill is a suburban area in Shropshire, situated on the banks of the River Severn at an elevation of around 96 metres. Blists Hill lies near the historic towns of Madeley and Coalport, and is within commuting distance of Wolverhampton. Blists Hill has a population of approximately 2602 people, predominantly living in detached houses. Blists Hill is located in a scenic area, with the Shropshire countryside and the Ironbridge Gorge nearby.
Fuel drain cover around Blists Hill and across Shropshire
Blists Hill waits in the TF postcode area, and our vans that answer petrol in diesel calls there work the places around it as well — Madeley, Sutton Hill and Coalport among them. The vehicle does not need to move to us: we drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Blists Hill: still at the petrol pump?
The best place there is, then — that is where you are. Phone, and leave it turned off.