Should You Worry? Petrol in a Diesel Car in South Side
Far less than you probably are, provided it has not been started. Until your ignition primes your pump, the starter cranks, or your car is driven, petrol in a diesel tank simply rests there and does nothing. Which means the honest reply to the first South Side question — "have I ruined it?" — usually no. Petrol in Diesel is who to ring, with your engine left off, and so it remains that way. Read on for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and ways to make sure you never do it again.
Inside your engine: what petrol in a diesel does
Passing through a motor, diesel is doing two things at once. It lubricates to begin with, and only then does it burn. The high-pressure fuel pump and the fuel injectors are designed to extremely fine tolerances, and your diesel passing through them is what keeps those surfaces from grinding against one another.
Petrol handles the first job badly and the second not at all. Being less viscous than diesel, petrol strips away the protection a fuel system needs, leaving a pump on the mixture to wear itself. It is equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the knocking.
Put these together and the shape of the issue is clear. Not contact but circulation is what does the harm. Any tank with petrol in it is a fuel problem. A pump that has been working on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with the fuel to the fuel injectors further on.
Petrol in a diesel in South Side: how bad is it? Four situations
The best case there can be: filled up, not once started. The petrol is in your tank and just your tank, and the task is a drain and a flush where your car sits. This is the one scenario that can only really happen at a forecourt, as anywhere else the car has been driven to get there.
Ignition on, or started for a moment. The fuel system has been bled, and so petrol has left the tank and reached your filter and the fuel lines. Usually little more than emptying, purging and sorting the filter, so still easy.
The pump has worked a few miles on thinned fuel — that is what driving it does. Mileage is only half of it; how hard it was driven counts equally. Either way the work runs to that tank, the fuel lines, the fuel filter and fresh fuel through the entire system. The school run to the local primary school is one thing. Any miles on the M8, under 10 miles from South Side, means your engine working hard throughout, and a run to Edinburgh, under a mile away, is a very different job too.
Driven on until it protested — knocking, smoke, an uneven idle, a soft throttle. That's the motor telling you its fuel has stopped acting like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Crichton Street. The drain and flush-through still come first, and they take care of it: when a vehicle is stopped quickly, permanent damage is very uncommon.
What South Side people 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. Topping up takes out nothing; it gives you a fuller tank of the same mixture. That guidance supposes a diesel fuel system handles petrol by percentage. It does not.
If anything, the reverse holds. Myth: "A newer diesel can cope with a bit of petrol." Smaller components and higher pressure are the way a newer diesel runs its fuel, and that makes the lubrication count more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up most drivers than any other. A petrol engine fed diesel generally will not run, so the motorist stops and the harm stops with them. While your pump grinds, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. A running engine does not mean fine.
An old workaround for a different problem lies behind this one. Myth: "Add some two-stroke oil and drive it home." That petrol is still inside the tank after that, and whatever it has thinned isn't put back.
Once the motor has been run, part of that petrol is in the fuel filter and your lines, not that tank — and your next start sends it right back through the pump. So the myth "drain the tank yourself and you're sorted" does not hold. It is also truly hazardous to drain petrol into a can by the kerbside.
How does petrol in a diesel take place?
It is rarely carelessness, and nobody does it on purpose. One way only, because of the nozzles: the smaller petrol one slips inside a diesel filler with almost no resistance, while the diesel one mostly won't fit a petrol motor. That is how the forecourt makes it straightforward.
It occurs when routine and the vehicle stop matching. Courtesy car, hire car, or a motor that's new. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps laid out differently. A rushed fill on the way to Edinburgh Waverley with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. Add rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
Preventing petrol in a diesel next time you fill up in South Side
- Read the pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on every forecourt. The label is what matters.
- The first fill in a strange motor is the time to check your filler flap — on it, or on the cap, many motors state the fuel they take.
- Mark your key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It sounds silly and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away then keep your mind on the petrol pump.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to reject a petrol nozzle, and aftermarket devices exist for the rest. Count it as a backstop, and keep checking the pump.
- Spotting it mid-fill? Stop there and then. A thinner mixture results from less petrol in your tank, but the next step remains the same: don't start it.
South Side: already put petrol in a diesel?
The order of things is brief, then. Leave it unstarted, with the ignition switched off as well. If you are still at the forecourt — JET or anywhere else — ask the staff to help you push it clear of the petrol pump. Phone 0333 366 0103 next, with three facts — the fuel, the approximate amount, and whether it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a separate problem — South Side has a page all for it.
One petrol in a diesel task around South Side costs more than another. Why?
Four separate tasks sit behind the four situations above — which is why there is no honest single price. The situation itself does most of the work of moving your cost. Where your car is matters too, and whether a technician can safely reach it, after the ratio of petrol to what the tank takes.
That is why our engineers ask three queries before costing instead of after: what got in, how much, and if it's run. A range turns into a straight figure when the answers are in.
About South Side
South Side is a suburban area in the City of Edinburgh, situated near the coast and close to the city centre. South Side sits at an elevation of 87 metres, overlooking the surrounding landscape. South Side is predominantly composed of flat-type housing, which accommodates a significant portion of the local population. South Side is located near other Edinburgh neighbourhoods, including Dumbiedykes and Old Town.
South Side and City of Edinburgh: where our fuel drain cover reaches
Petrol in diesel calls around South Side — part of the EH postcode area — go to teams that also cover the spots round it, Dumbiedykes, Roxburghs Court and Old Town included. We drain where your vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
South Side: still at the petrol pump?
Nothing beats it: that is where you are. Keep the vehicle turned off, then ring.