Should You Worry? Petrol in a Diesel Car in Southlands
Probably less than you already are — provided no one has started it. Everyone in Southlands starts with "have I ruined it?", and the fair answer is generally no: petrol resting in your tank of any diesel remains harmless till priming, cranking or driving draws it into your fuel system. Leave the engine off and ring Petrol in Diesel — that keeps it that way. Keep reading for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and the way to make sure you never repeat it.
The engine and petrol in a diesel: what happens
Passing through a motor, diesel is doing two jobs at once. Before it ignites, it lubricates — and then it ignites. Made to very fine gaps, the injectors and your pump rely on the diesel moving through them to keep their surfaces from wearing against one another.
The second job petrol doesn't do at all, and the first it does poorly. The knocking comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips out the lubrication your system hinges on, and any pump working on that mix is wearing itself.
Together, those leave the shape of the trouble clear. Contact doesn't do the harm — movement does. Where the petrol is only inside your tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds travels on, borne by your fuel, into the injectors further along, which is why a pump that has been working on that petrol is where a mechanical problem begins.
How bad is petrol in a diesel? Four situations our technicians see in Southlands
Fuelled up, never started. The best case there is. Only the tank has petrol in it, and so the job is emptying your tank and cleaning the system where the car stands. This situation can only really take place on a forecourt: anywhere else, your car got there by being driven.
A brief spell of running, or just the ignition on. Once primed, the fuel system has pulled petrol from that tank as far as the fuel filter and the fuel lines. Still generally straightforward: drain, flush, and the filter sorted.
Your pump now worked a few miles on thinned fuel — that's what driving it meant. How hard the vehicle was driven matters as much as how far, and this work covers that tank, the lines, the fuel filter and clean fuel through the whole circuit. Driving the children to Holy Trinity Church of England VC Primary School & Community Nursery is one kind of trip. Getting as far as Wells, under 50 miles away, makes a very different task — as does any miles on the M5, under 50 miles from Southlands, with the motor running hard the whole time.
Clattering, a ragged idle, smoke, a throttle gone soft: driven until it complained. That's the engine telling you its fuel has stopped acting like diesel. Leave it where it stops: a lay-by, a quiet street, the verge on Cleves Close. Lasting damage is very rare if a car is pulled over early, and the drain and flush-through that still come first deal with it.
What Southlands motorists get told about petrol in a diesel — and the myths in it
Myth: topping up to full with diesel makes it fine. It doesn't. A bigger tank of the same mix is all it gives, since topping up removes nothing. The assumption behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: a modern diesel copes with a bit of petrol. Rather, the opposite. Smaller parts and higher pressure are the way a modern diesel runs its fuel, and that makes the lubrication matter more, not less.
The myth that catches motorists out: if it starts and drives, it must be unharmed. A petrol motor fed diesel normally will not run, so the driver stops and the damage stops with them. Feed petrol to a diesel and it normally starts, idles and pulls away like nothing happened — all the while its pump wears. Running is not the same as fine.
An outdated workaround for a different fault is behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has diluted stays diluted, and the petrol stays inside your tank anyway.
Myth: "Drain the tank yourself and you're sorted." After the engine has been run, some of that petrol is no longer inside that tank: it's in your filter and the fuel lines, and it goes right back through your pump on your next start. Besides, petrol cleared into a can by the road is truly risky.
How does petrol in a diesel happen?
A careless moment is rarely the cause, and nobody means to do it. A diesel nozzle mostly will not fit a petrol motor, yet the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and only in one direction.
It happens when habit and the car stop matching. Hire cars, courtesy cars, and motors that are new to you. One petrol and one diesel on the driveway of the same household. The pumps in a different order on a familiar forecourt. Filling up in a rush on the way to Weymouth, with a train to catch. Exactly the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Tiguan for the first time. Add a back seat full of kids, a phone call or rain, and habit takes over.
Next time you fill up around Southlands: preventing petrol in a diesel
- A green handle for unleaded and black for diesel is normal in the UK — but not on every forecourt. Trust the label on the petrol pump, not the colour.
- The first fill in a new car is the time to check the filler flap — inside 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 intending to remember, for a home with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump. It sounds silly and it does the trick.
- Mistakes like this are easy to make while your mind is on something else, and so the 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 reading the petrol pump.
- Less petrol means a thinner blend, and so stop the moment you realise — though remembering that the next stage is unchanged. It is still not to crank it.
Petrol already in a diesel in Southlands? Start here
The order of things is short, then. Leave it unstarted, with your ignition switched off too. Ask the attendants to help you roll it away from the petrol pump if you're still at the forecourt, whether that's Esso or anywhere else. Next, 0333 366 0103. We'll ask what got in, about how much, and if it has been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a separate issue — Southlands has a page all for it.
One petrol in a diesel task in Southlands costs more than another. Why?
An honest single price doesn't exist here: four situations, four separate tasks. Which of them you are in is mostly what shifts your cost. Next it's the share — how much petrol got in against how much that tank holds — and then where your car is and whether our van can reach it safely.
Three queries come first, before quoting, rather than 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 Southlands
Southlands is a coastal suburban area in Dorset, situated near the towns of Wyke Regis and Weymouth. Southlands has a population of around 3931 people and is characterized by its semi-detached housing stock. Southlands is located at a low elevation of 12 metres above sea level, close to the sea. Southlands is also within commuting distance of larger towns, with Wells being the nearest city at 43.1 miles away.
Fuel drain cover across Dorset, Southlands included
Wyke Regis, Rodwell and Weymouth are among the places near Southlands that the same teams work, answering petrol in diesel call-outs across Southlands's DT postcode area. You need not move the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
At the petrol pump around Southlands, still?
Then, you couldn't be in a better place. Keep it off. Phone.