Moredun: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less anxious than you likely are. Petrol resting in a diesel tank does nothing to your engine till something draws it through the system — your ignition priming the pump, your starter, or driving itself. So the honest answer to the first query anyone around Moredun asks, "have I wrecked it?", is normally no. Leave the motor off and call Petrol in Diesel — that keeps it that way. What petrol really does to a diesel, how to gauge how far it's gone, and how to stop it from happening a second time: that is the rest of this page.
Petrol in a diesel: what does it do to the engine?
Passing through an engine, diesel is doing two things at once. It combusts, and before it ignites it protects. Built to extremely fine clearances, your injectors and the pump rely on the diesel moving through them to stop their surfaces wearing against one another.
Of these two tasks, petrol manages the first badly and the second never. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, leaving a pump running on the mixture wearing itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the clattering.
Put those together and the shape of the issue is clear. Contact does not do the harm — movement does. Any tank with petrol in it is a fuel issue. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to your injectors further on.
How bad is petrol in a diesel? Four situations our technicians see around Moredun
Fuelled up, not once started. The best case there is. The petrol is in your tank and only that tank, and the job is a drain and a flush where the vehicle stands. This is the one situation that can only really occur at a forecourt, as anywhere else the vehicle has been driven to get there.
Your ignition turned on, or a brief start. Once primed, the fuel system has drawn petrol from that tank as far as the fuel filter and the lines. Still usually easy: drain, flush, and the filter seen to.
Your pump now worked a few miles on thinned fuel — that is what driving it meant. Mileage is only half of it; how hard it was driven counts just as much. Either way the work runs to that tank, your lines, your filter and clean fuel through the whole system. Short trips, like the school run to the local primary school, are one thing. Very different again: a trip to Edinburgh, under 5 miles away, or some miles on the M8, under 10 miles from Moredun, where the engine never stopped working hard.
Driven on until it protested — knocking, smoke, an uneven idle, a soft throttle. That's your motor telling you its fuel no longer is acting like diesel. Whether it's the verge on Moredun Park Street, a lay-by or a side road, stop where you are then leave it. Long-term damage is very uncommon if a car is stopped soon, and the drain and flush that still come first take care of it.
Moredun motorists and the petrol in a diesel myths they hear
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. Percentage is not how a diesel fuel system copes with petrol, whatever that advice presumes.
Not so: a modern diesel copes with a bit of petrol. Rather, the opposite. More precise components and higher pressure are how a current diesel runs its fuel, and that makes the protection matter more, not less.
One myth that catches people out: if it starts and drives, it must be unharmed. Feed diesel to a petrol motor and it normally will not run, so the motorist stops — and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump grinds. Fine and running are not the same at all.
Not so: a two-stroke additive makes it safe to drive home. It was an old workaround, supposed for another issue. None of what petrol thinned is put back by it — and afterwards, your tank still contains the petrol.
Myth: "Drain the tank yourself and you are sorted." Once the engine has been run, some of that petrol is no longer in that tank: it is in the fuel filter and the fuel lines, and it goes right back through the pump at your next start. It's also truly hazardous to drain petrol into a can by the roadside.
How does petrol in a diesel take place?
No one does it on purpose, and it is rarely carelessness. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol motor at all. So the error runs one way.
The moment routine stops matching the car is the moment it occurs. Any car that's new to you — a hire car, on loan as a courtesy car, or just bought. Two cars on one drive, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. A rushed fill en route to Newcraighall with a train to catch. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. With rain, a call coming in, or children to deal with, the hand just does what it has always done.
Preventing petrol in a diesel next time you fill up around Moredun
- Green for unleaded and black for diesel is usual in the UK — but not on each forecourt. Go by the label on the petrol pump, not the colour.
- Plenty of vehicles state the fuel inside the filler flap or on the cap, so check it on the first fill in any vehicle you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember, in a home with one of each.
- Before the nozzle leaves the pump the first time you fill a hired or new motor, say "diesel" aloud. Daft, perhaps, but it does the trick.
- While you're thinking about something else, this is an easy mistake to make — so tuck your phone away.
- 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 reading the petrol pump.
- The moment you realise, stop: less petrol in your tank means a thinner blend. What to do next doesn't change, though — still do not start the car.
Moredun: already put petrol in a diesel?
Then, there's just a short order of things. Do not switch your ignition on, and don't start it. The attendants at the forecourt — whether at Morrisons itself or wherever you filled up — will usually help roll it away from the petrol pump if you ask. Ring 0333 366 0103 next, with three facts — the fuel, the rough quantity, and whether it's run.
Corrosion and deposits are the issue with AdBlue, where petrol brings lost protection. So if it was AdBlue, say so — and read its own Moredun page.
Moredun petrol in a diesel jobs: why one costs more than another
The four situations above are four different jobs, so no single price for this would be honest. Mostly, your cost shifts with which one you're in. Next it's the proportion — how much petrol got in against how much the tank holds — and after that where your car is and whether a van can reach it safely.
Ahead of any quote, not after, come three questions: the fuel that got in, its quantity, and if it's run. That is why. Those replies are what turn a range into one firm number.
About Moredun
Moredun is a suburban area in the City of Edinburgh, situated near the River Esk and close to the city centre. Moredun sits at an elevation of 88 metres, with semi-detached housing being the predominant type of accommodation. Moredun is located near other suburban areas such as The Inch, Gilmerton, and Gracemount, and is approximately 3.4 miles from Edinburgh city centre.
Moredun and City of Edinburgh: where our fuel drain cover reaches
The teams answering petrol in diesel calls in Moredun, in the EH postcode area, also work the locations near it, The Inch, Gilmerton and Gracemount included. No need to move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
In Moredun and still at the pump?
No position is better: that's where you now are. Ring, and leave it switched off.