How Worried Should You Be? Petrol in a Diesel Car in Bilston
If it hasn't been started, you can worry far less than you likely are. Petrol resting in a diesel tank does nothing to your engine till something pulls it through the system — the ignition priming the pump, the starter, or driving itself. So the fair answer to the first query anyone in Bilston asks, "have I ruined it?", is normally no. To keep the car like that, ring Petrol in Diesel then leave your motor switched off. What petrol really does to a diesel, how to judge how far it's gone, and how to stop it from happening again: that is the rest of this page.
What petrol in a diesel does to your engine
Passing through an engine, diesel is doing two jobs at the same time. It ignites, and before it burns it lubricates. What keeps the surfaces inside the high-pressure pump and your injectors from wearing down against one another is the diesel flowing through them — they're built to very fine clearances.
Petrol handles the first job badly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump on the mixture wearing itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the rattling.
Put these together and the shape of the trouble is clear. The harm is done by movement, not by contact. Where the petrol is only in your tank, it is a fault of fuel, nothing more. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to your injectors downstream.
Four scenarios our engineers see in Bilston: how bad is petrol in a diesel?
Filled up, not once started. The best case there is. Just that tank has petrol in it, so the task is draining that tank and rinsing the system where your car stands. This situation can only truly happen at a forecourt: anywhere else, the vehicle got there by being driven.
Started for a second, or only your ignition on. Petrol has left your tank and got to your filter and the fuel lines, because the system has been primed. That's generally still a simple task — a drain, a flush, and the filter seen to.
Your pump has spent a few miles on diluted fuel — that's what driving it meant. How hard your car was driven matters as much as how far, and this work takes in that tank, the lines, the filter and fresh fuel through the whole circuit. On the school run to Loxdale Primary School, the distance is small. Driving as far as Wolverhampton, under 3 miles away, makes a very different task — as does any mileage on the M6, under 3 miles from Bilston, with the motor working hard all the way.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone uneven. The fuel isn't behaving like diesel any more, and your engine is saying so. Whether it's the verge on High Street, a lay-by or a side street, stop where you are then leave it. A car stopped quickly very rarely has long-term damage, as the drain and the flush, which still go first, deal with it.
What Bilston drivers get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. A bigger tank of the same mixture is all it gives, since topping up removes nothing. The assumption behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A newer diesel can cope with a bit of petrol." Lubrication matters more on modern diesels, not less, because their fuel runs through more precise components at higher pressure.
"It starts, it drives, so no harm done" — the myth that catches most drivers than any other. A petrol engine fed diesel normally won't run, so the driver stops and the damage stops with them. Feed petrol to a diesel and it normally fires up, ticks over and pulls away like nothing has happened — all the while its pump is wearing. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an old workaround for a distinct fault. It doesn't put back what petrol has thinned, and the petrol is still in that tank after that.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol sits in the filter and lines, ready to go right back through your pump on the next start. It is also really risky to drain petrol into a can at the kerbside.
How petrol ends up: petrol in a diesel
Carelessness is seldom the cause, and nobody means to do it. A diesel nozzle mostly will not fit a petrol car, yet the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and just in one direction.
It happens when habit and the car stop matching. A new car, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. Your usual forecourt, its pumps now in a different order. Fuelling up in a rush on the way to Coseley, with a train to catch. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. Add rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Preventing petrol in a diesel next time you fill up in Bilston
- Green for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Trust the label on the pump, not the colour.
- In a vehicle you do not know, look inside the flap over your filler or at the cap before your first fill: plenty of cars print the fuel type there.
- One of each in the home? Mark the key to your diesel — a bright fob, a sticker — since intending to remember isn't enough.
- It sounds silly and it works: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump.
- Put the phone away. This is an easy mistake to make whilst you're thinking about something else.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Spotting it mid-fill? Stop at once. A weaker mixture follows from less petrol inside the tank, but the next step stays the same: do not fire it up.
Put petrol in a diesel around Bilston already?
Short and simple, then, is the order of things. Don't switch your ignition on, and don't start it. If you are still on the forecourt — Shell or anywhere else — ask the attendants to help you roll it away from the petrol pump. Next, 0333 366 0103. We'll ask what was put in, about how much, and if it's been run.
Say so if it was AdBlue rather than petrol: it is a different problem, with its own page for Bilston, because AdBlue brings corrosion and deposits instead of lost protection.
Bilston petrol in a diesel tasks: why one costs more than another
The four situations above are four separate tasks, so no single price for this would be honest. The situation itself does most of the work of moving your cost. Where your car is counts too, and whether a van can safely reach it, after the share of petrol to what your tank holds.
Three queries come first, before any quote, rather than after — what got in, how much, has it run — and this is the reason. Their answers are what change a range into one firm number.
About Bilston
Bilston is a town situated on the River Tame in the West Midlands, approximately 2.6 miles southeast of Wolverhampton. Bilston sits at an elevation of around 146 metres, with nearby neighbourhoods including Millfields, Freezeland, and Green Lanes. Bilston has a population of around 24,798 people, predominantly living in semi-detached housing. Bilston is located about 110.5 miles northwest of London, making it a commuter town with access to major cities.
Fuel drain cover around Bilston and across West Midlands
Bilston waits in the WV postcode area, and our teams that answer petrol in diesel calls there work the places near it as well — Millfields, Freezeland and Green Lanes among them. A forecourt, a supermarket car park, a lay-by or your own drive are all spots we drain, and your car doesn't need to come to us.
Bilston: still at the petrol pump?
Then you are in the best position there is. Turned off it stays; then ring.