Petrol in a Diesel Car in Worldsend: How Worried Should You Be?
Unstarted? Then less anxious than you likely are. Everyone in Worldsend starts with "have I ruined it?", and the fair answer is usually no: petrol left inside the tank of any diesel stays harmless till priming, cranking or driving pulls it into your fuel system. Petrol in Diesel is who to call, with the motor left off, and so it remains that way. Below, you will find what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you again.
The motor and petrol in a diesel: what goes on
Passing through an engine, diesel is doing two jobs at the same time. It burns, and before it combusts it lubricates. Designed to very fine gaps, the fuel injectors and your pump rely on the diesel flowing through them to stop their surfaces wearing against one another.
Badly at the first, not at all at the second: that is 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's where the clattering comes from.
Combined, those leave the shape of the issue clear. The damage is done by movement, not by contact. Where that petrol is only inside your tank, it's an issue of fuel, nothing more. Whatever a worn pump sheds goes on, carried by your fuel, into the fuel injectors downstream, which is why a pump that has been working on the petrol is where a mechanical problem starts.
Four situations our engineers see in Worldsend: how serious is petrol in a diesel?
The best case there can be: filled up, never started. On a forecourt, and genuinely only there, the petrol is still confined to the tank — since anywhere else the vehicle was driven to get to it. The task is emptying and purging on the spot.
A brief spell of running, or just your ignition on. With your system primed, your lines and filter now contain petrol that has come from the tank. Drain, flush, see to your filter: still normally simple.
Driven a couple of miles. Now the pump has spent those miles running on diluted fuel. Tank, lines, filter, then fresh fuel run through the entire circuit: that is this work, and the way the car was driven matters as much as the mileage. The school run to St Lawrence CofE Primary School is one matter. Driving as far as Wolverhampton, under 50 miles away, makes a very different task — as does any distance on the M54, under 25 miles from Worldsend, with the motor labouring hard the whole time.
Knocking, a ragged idle, smoke, a throttle gone soft: driven till it complained. The fuel is not acting like diesel any more, and the motor is telling you. Leave it where it has stopped: a lay-by, a side street, the verge on Ludlow Road. Lasting damage is very uncommon if a car is pulled over quickly, and the drain and flush that still go first take care of it.
Worldsend drivers and the petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. A bigger tank of the same mixture is all it gives, because topping up removes nothing. The idea behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." At higher pressure, through more precise components: that is how a modern diesel moves its fuel, so the protection counts more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools people. The driver of a petrol motor fed diesel normally has no choice but to stop, because it will not run, and the damage stops there. 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. Fine and running aren't the same at all.
Not so: a two-stroke additive makes it safe to drive home. It is an old fix, supposed for another fault. It doesn't put back what petrol has weakened, and that petrol is still in that tank afterwards.
Myth: "Drain that tank yourself and you are sorted." After the motor has been run, some of the petrol is no longer in the tank: it's in the fuel filter and the fuel lines, and it goes straight back through your pump at the next start. It is also really risky to drain petrol into a can by the roadside.
How petrol ends up: petrol in a diesel
On purpose? Never. Through carelessness? Seldom, if ever. One way only, since of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol car. That's how the forecourt makes it simple.
It occurs when routine and your car stop matching. Hire cars, courtesy cars, and motors that are new to you. A household with one petrol and one diesel on the driveway. A well-known forecourt with the pumps in a different order. Rushing for a train at Church Stretton and filling up en route. A new-to-you diesel Renault Clio, its first fuelling, and a driver accustomed to petrol: precisely when it occurs. With rain, a call arriving, or a car full of children to deal with, the hand just does what it has always done.
Worldsend people: how to prevent petrol in a diesel next time
- The label is what matters, and so check the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- Many cars state the fuel type inside the filler flap or on the cap, and so check there on your first fill in a vehicle you do not know.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a house with one of each.
- It seems silly 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 petrol pump.
- Mistakes like this are simple to make whilst your mind is on something else, and so the phone goes away.
- Some diesels come with a filler built to reject a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- As soon as you notice, stop: less petrol inside that tank makes a weaker mix. What to do next doesn't change, though — still don't crank it.
Worldsend: already put petrol in a diesel?
Then the order of things is short. Starting it is out, and so is turning on the ignition. Yet at the forecourt, at Applegreen or anywhere else? Ask the staff to help you push the car clear of the petrol pump. Then ring 0333 366 0103 and tell us what went in, about how much, and if it has run.
If it was AdBlue instead of petrol, say so. That's a separate problem — corrosion and deposits rather than lost protection — and it has its own page for Worldsend.
What makes one Worldsend petrol in a diesel job cost more than the next
An honest single price does not exist here: four scenarios, four separate jobs. What moves the cost is chiefly which of them you are in. Where the car is counts too, and whether a technician can safely get to it, after the proportion of petrol to what that tank holds.
What was put in, how much, and whether it's run — three questions we ask before quoting, not after, for precisely that reason. Those answers change a range into a straight figure.
About Worldsend and where it is
Worldsend is a suburban area situated on the riverside in Shropshire, with a mix of detached housing and a population of around 2321 residents. Worldsend sits at an elevation of 194 metres, near the market town of Church Stretton and other nearby places such as Cunnery and Ashbrook. Worldsend is located approximately 28.8 miles from Wolverhampton and 134.4 miles from London, in the West Midlands region. Worldsend has a relatively quiet setting, with the River Severn flowing through the surrounding countryside.
Fuel drain cover across Shropshire, Worldsend included
Worldsend rests in the SY postcode area, and our teams that answer petrol in diesel jobs there work the places around it as well — Church Stretton, Cunnery and Ashbrook among them. Our technicians drain where your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the pump around Worldsend, still?
Then you're in the best spot there is. Keep it off. Phone.