Petrol in a Diesel Car in Southmead: How Worried Should You Be?
Less than you likely are, if it hasn't been started. Petrol sitting in a diesel tank does nothing to your motor until something pulls it through your fuel system — your ignition priming the pump, your starter, or driving on its own. So the honest answer to the first question anyone around Southmead asks, "have I ruined it?", is generally no. Leave the engine off and phone Petrol in Diesel — that keeps it that way. What petrol actually does to a diesel, how to gauge how far it has gone, and how to stop it from happening a second time: that is the remainder of this page.
Inside the engine: what petrol in a diesel does
Passing through an engine, diesel is doing two jobs at the same time. It combusts, and before it ignites it protects. What stops the surfaces inside the high-pressure fuel pump and the fuel injectors from wearing against each other is the diesel flowing through them — they're built to very fine tolerances.
Petrol does the first task badly and the second not at all. A pump working on a petrol mixture is wearing itself out, since petrol is runnier than diesel and takes away the protection the fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where any rattling comes.
Put those together and the shape of the issue is plain. It is movement that does the damage, not contact. All a tank with petrol in it amounts to is a fuel issue. The beginning of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with the fuel to your injectors downstream.
Southmead, petrol in a diesel: four situations, from mild to major
Filled up, never started. The best case there can be. At a forecourt, and genuinely only there, that petrol is still confined to your tank — since everywhere else the car was driven to get to it. The job is draining and rinsing on the spot.
A moment's running, or just your ignition on. Petrol has left your tank and reached the filter and the fuel lines, since your system has been bled. Still generally simple: drain, flush, and the filter dealt with.
Driven a few miles. Now your pump has spent those miles working on thinned fuel. How hard the car was driven counts as much as how far, and this work takes in your tank, the fuel lines, the fuel filter and clean fuel through the entire system. Driving the kids to St Teresa's Catholic Primary School is one sort of trip. Any miles on the M32, under 3 miles from Southmead, means the motor working hard throughout, and a run to Bristol, under 5 miles away, is a very different task as well.
Driven on until it protested — clattering, smoke, a ragged idle, a soft throttle. The motor is telling you your fuel is no longer acting like diesel. Leave it wherever it stops: a lay-by, a side street, the verge on Greenway Drive. What comes first is still the fuel drain and flush-through, and that sorts it out, with long-term damage very uncommon when a vehicle is stopped soon.
What Southmead people get told about petrol in a diesel — and the stories in it
Myth: topping up to full with diesel makes it fine. It doesn't. A bigger tank of the same mixture is all you get, since topping up takes out nothing. A diesel fuel system does not accept petrol by percentage in the way that guidance presumes.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." Lubrication matters more on modern diesels, not less, because their fuel runs through smaller components at higher pressure.
This is the one that fools motorists. Myth: "If it starts and drives, there's no damage done." Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the harm. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile the pump wears. Being able to run is not proof of being fine.
An old workaround for a distinct problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has diluted stays weakened, and that petrol stays in the tank regardless.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol sits in your filter and lines, ready to go straight back through your pump at the next start. Also, a can of petrol drained at the roadside is genuinely risky.
How does petrol in a diesel take place?
A careless moment is rarely the cause, and nobody means to do it. One way only, since of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, while the diesel one mostly will not fit a petrol motor. That is how the forecourt makes it simple.
The moment habit stops matching your car is the moment it occurs. A new vehicle, a hire car or a courtesy car. One petrol and one diesel on the drive of the same household. A forecourt you know, only with its pumps laid out differently. A rushed fill on the way to Filton Abbey Wood with a train to catch. Years of petrol vehicles behind you, a diesel Renault Clio in front of you at the forecourt for its first tank — that's when. With rain, a call coming in, or a car full of children to deal with, the hand simply does what it has always done.
Next time you fill up around Southmead: preventing petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on every forecourt. The label is what counts.
- Plenty of vehicles state the fuel inside your filler flap or on the cap, so check it on your first fill in a car you do not know.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, for a house with one of each.
- "Diesel", out loud, before you pick up the nozzle — every time a new or hired car needs its first tank. It seems daft. It does the trick.
- Mistakes like this are straightforward to make whilst your mind is on something else, so your phone goes away.
- Some diesels have a filler designed to block a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Less petrol makes a weaker mix, and so stop the moment you realise — though remembering that the next stage is unchanged. It is still not to crank it.
Put petrol in a diesel in Southmead already?
In that case, there's just a short order of things. Leave it unstarted, with your ignition switched off too. The staff on the forecourt — whether at Esso itself or wherever you filled up — will usually help roll it away from the petrol pump if you ask. Next, 0333 366 0103. We'll ask what got in, roughly how much, and if it's been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate issue — Southmead has a page all for it.
What makes one Southmead petrol in a diesel job cost more than the next
Four separate tasks lie behind the four scenarios above — which is why there's no fair single quote. The situation itself does most of the work of moving your cost. Where your car is matters too, and whether our van can safely get to it, after the ratio of petrol to what that tank holds.
Three questions come first, before quoting, instead of after — what was put in, how much, has it run — and that is the reason. Those answers change a range into a straight figure.
About Southmead, for a moment
Southmead is a suburban area in Bristol, situated near the River Trym and approximately 3.2 miles from the city centre. Southmead sits at an elevation of around 64 metres, with semi-detached housing being the predominant type of accommodation in the area. Southmead is close to other nearby suburbs, including Brentry, Horfield, and Henleaze, and is located within the South West region of England, about 106 miles west of London.
Across Bristol and in Southmead: fuel drain cover
Petrol in diesel call-outs in Southmead — part of the BS postcode area — go to vans that also cover the places about it, Brentry, Horfield and Henleaze among them. The car doesn't need to move to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
In Southmead and still at the petrol pump?
Then, you could not be in a better place. Keep it off. Phone.