How Worried Should You Be? Petrol in a Diesel Car in Tradeston
Less than you likely are, if it hasn't been started. "Have I wrecked it?" is the first thing anyone around Tradeston asks, and the honest answer is normally no, since petrol left in a diesel tank hurts nothing till it is dragged through the system — by ignition priming, by the starter, or by driving. Leave the engine off then ring Petrol in Diesel — that is how you keep it that way. The rest of this page explains what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Petrol in a diesel: what does it do to the engine?
On its way through a motor, diesel has two tasks. Before it burns, it protects — then it ignites. Built to very fine clearances, the injectors and the pump depend on the diesel moving through them to stop their surfaces wearing against one another.
Of these two tasks, petrol manages the first poorly and the second never. It's runnier than diesel and strips away the protection the fuel system depends on, and so a pump running on a petrol mix 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 knocking comes from.
The shape of the problem is plain once you put those together. Contact does not do the damage — movement does. Where that petrol is only inside that tank, it's a problem of fuel, nothing more. The start of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to your injectors downstream.
Four situations our engineers see in Tradeston: how bad is petrol in a diesel?
Fuelled up, never started. The best case there is. Just the tank has petrol in it, and so the job is draining that tank and purging the system where your car stands. This scenario can only really occur on a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a moment. Once primed, your system has pulled petrol out of your tank up to the filter and the lines. Still usually simple: drain, flush, and the filter sorted.
The pump has spent a few miles on weakened fuel — that is what driving the vehicle does. Mileage is only half of that; how hard it was driven counts just as much. Either way the work runs to your tank, your lines, your filter and clean fuel through the whole system. On the school run to the local primary school, the mileage is short. Very different a second time: a trip to Glasgow, under 3 miles away, or some mileage on the M74, under a mile from Tradeston, where the engine never stopped working hard.
Driven until it protested. Rattling, a ragged idle, smoke, a throttle that has gone soft. The engine is telling you the fuel is no longer behaving like diesel. Leave it where it stops: a lay-by, a side street, the verge on Scotland Street. What goes first is still the fuel drain and flush-through, and that takes care of it, with permanent damage very uncommon when a car is stopped soon.
What Tradeston 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 mix is all you get, because topping up takes out nothing. That guidance assumes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. Protection counts more on newer diesels, not less, since their fuel passes through smaller parts at higher pressure.
Myth: "If it starts and drives, there's no damage done." This is the one that catches drivers. A petrol motor fed diesel usually will not run, and so the driver stops and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile the pump grinds. Fine and running are not the same thing.
Myth: a two-stroke additive makes it safe to drive home. It was an old workaround, supposed for another fault. It doesn't put back what petrol has weakened, and the petrol is still inside that tank later on.
The next start draws petrol back round your pump from your lines and your filter, where some of it ends up once the engine has run. That is why draining the tank yourself doesn't sort it — a myth. Draining petrol into a can at the roadside is also truly risky.
Why petrol in a diesel occurs at all
Carelessness is seldom the cause, and no one means to do it. A diesel nozzle mostly won't go into a petrol car, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and only in that direction.
Routine and your car falling out of step is when it occurs. Any vehicle that's new to you — hired, on loan as a courtesy car, or just bought. Two motors on one driveway, one petrol, one diesel. A forecourt you know, only with its pumps laid out differently. A hurried fill on the way to Pollokshields East with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it happens. Throw in rain, a phone call or a back seat full of kids, and your hand does what it has always done.
Tradeston people: how to prevent petrol in a diesel next time
- Check the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, yet not on every forecourt. The label is what matters.
- Plenty of cars state the fuel inside the filler flap or on the cap, so check there on the first fill in any motor you don't know.
- One of each in the house? Mark the key to the diesel — a bright fob, a sticker — since intending to remember isn't enough.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car gets its first tank. It sounds silly. It does the trick.
- Put the phone away. This is an easy mistake to make while you are thinking about something else.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- The moment you realise, stop: less petrol inside your tank makes a thinner mix. What to do next doesn't change, though — still do not fire it up.
Petrol already in a diesel around Tradeston? Begin here
Then, there's just a short order of things. Do not switch the ignition on, and do not crank it. Ask the staff to help you push it away from the pump if you're still at the forecourt, whether that's Shell or somewhere else. Phone 0333 366 0103 next, with three facts — the fuel, the rough volume, and whether it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different problem — Tradeston has a page just for it.
Tradeston petrol in a diesel tasks: why one costs more than another
Four different tasks lie behind the four scenarios above — which is why there is no honest single price. What shifts the cost is mostly which of them you're in. Where the car is matters too, and whether a technician can safely reach it, after the proportion of petrol to what the tank takes.
Three questions come first, before any quote, instead of after — what was put in, how much, has it run — and this is the reason. Those answers change a range into a straight figure.
About Tradeston itself
Tradeston is a riverside suburban area in Glasgow City, situated near the River Clyde at an elevation of around 12 metres. Tradeston is close to the city centre, approximately 1.6 miles from Glasgow, and is surrounded by other nearby places such as Port Eglinton, Kingston, and Gorbals. Tradeston is predominantly composed of flat-type housing, which accommodates its population of around 3323 residents.
Tradeston and Glasgow City: where our fuel drain cover runs
Petrol in diesel jobs in Tradeston — part of the G postcode area — go to vans that likewise cover the spots about it, Port Eglinton, Kingston and Gorbals included. No need to bring your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places we drain.
At the petrol pump around Tradeston, still?
The best place there is, then — that is where you are. Turned off it remains; then phone.