Petrol in a Diesel Car in Comrie: How Worried Should You Be?
Probably less than you are now — as long as nobody has started the car. Till the ignition primes your pump, the starter turns, or the car is driven, petrol in a diesel tank just waits there and does nothing. Which makes the honest reply to that first Comrie query — "have I ruined it?" — normally no. Leave the motor off then phone Petrol in Diesel — that is how you keep it that way. The remainder of this page explains what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
Petrol in a diesel: what does it do to your engine?
Diesel has two tasks on its way through an engine. Before it ignites, it lubricates — then it burns. Very fine tolerances are built into your injectors and the high-pressure pump, and just the diesel flowing through keeps those surfaces from grinding together.
Badly at the first, not at all at the second: that's petrol. The rattling comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection your system rests on, and any pump running on that mix is wearing itself.
Put those together and the shape of the issue is plain. Contact doesn't do the damage — movement does. All a tank with petrol in it amounts to is a fuel problem. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the fuel injectors downstream.
Petrol in a diesel around Comrie: how bad is it? Four cases
Filled up, never started. The best case there is. That petrol is in that tank and only the tank, and the task is a drain and a flush where the car sits. This is the one situation that can only truly take place at a forecourt, because anywhere else the vehicle has been driven to get there.
Ignition on, or started for a second. With the system primed, your lines and filter now contain petrol that came from your tank. Normally nothing more than draining, cleaning and sorting the filter, and so still straightforward.
Those few miles on the road meant the pump labouring on fuel weakened by petrol throughout. The work is that tank, the lines, the fuel filter and fresh fuel through the whole system, and how hard the vehicle was driven counts as much as how far. On the school run to the local primary school, the mileage is small. Very different a second time: a run to Stirling, under 25 miles away, or any distance on the M9, under 15 miles from Comrie, where your engine never stopped working hard.
Driven on till it protested — clattering, smoke, a ragged idle, a soft throttle. The motor is telling you the fuel is no longer behaving like diesel. Pull up where you are — on the verge on Drummond Street, at the kerb, down a side road — and don't move it. The drain and flush still come first, and they take care of it: if a vehicle is stopped quickly, long-term damage is very rare.
Myths Comrie people hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing is removed by topping up — you're left with a fuller tank, still the same mix. The assumption behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: a newer diesel copes with a bit of petrol. If anything, the opposite. A modern diesel runs its fuel through finer components at higher pressure, which makes the lubrication matter more, not less.
"It starts, it drives, and so no harm done" — the myth that catches more people than any other. The driver of a petrol motor fed diesel normally stops, since it will not run, and the damage stops there. 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. A running engine doesn't mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an old fix for a separate problem. That petrol is still inside that tank afterwards, and what it has weakened isn't put back.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol sits in the filter and lines, ready to go right back through your pump on your next start. Clearing petrol into a can at the kerbside is also really dangerous.
Petrol in a diesel: how does it occur?
Nobody does it on purpose, and it's seldom carelessness. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle generally won't go into a petrol vehicle at all. So the error runs one way.
Habit and your car getting out of step is how it occurs. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. Your ordinary forecourt, its pumps suddenly in a different order. Filling up in a rush on the way to Gleneagles, with a train to catch. Years of petrol motors behind you, a diesel Volkswagen Tiguan in front of you at the forecourt for its first tank — that's when. Add rain, a phone call or a back seat full of children, and the hand does what it has always done.
Avoiding petrol in a diesel next time you fill up in Comrie
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what counts.
- In a car you do not know, look inside the flap over your filler or at the cap before your first fill: many motors state the fuel type there.
- One of each in the household? Label your key to the diesel — a bright fob, a sticker — since intending to remember is not enough.
- "Diesel", aloud, before you lift the nozzle — every time a new or hired car needs its first tank. It seems silly. It works.
- Thinking about something else is when this becomes an easy mistake to make, so tuck the phone away then keep your mind on the pump.
- Add-on devices exist for motors without one, and some diesels are built with a filler that will not take a petrol nozzle. Helpful — but a safety net at best, never a reason to stop checking the label.
- Less petrol means a thinner blend, so stop as soon as you notice — while remembering that the next stage is unchanged. It is still not to start the car.
Petrol already in a diesel in Comrie? Begin here
Short and simple, then, is the order of things. Starting it is out, and so is switching on your ignition. Still on the forecourt, at the nearest petrol station or anywhere else? Ask the attendants to help you roll it clear of the pump. Then ring 0333 366 0103 and tell us what was put in, about how much, and if it has run.
If it was AdBlue instead of petrol, say so. That's a separate problem — corrosion and deposits rather than lost protection — and it has its own page for Comrie.
Why one petrol in a diesel job in Comrie costs more than another
There's no fair single quote for this, because the four situations above are four different jobs. Mostly, your cost shifts with which one you are in. Where the vehicle is matters too, and whether a technician can safely reach it, after the proportion of petrol to what the tank takes.
Ahead of any quote, not after, we ask three queries: the fuel that was put in, its amount, and if it's run. That's why. Given those replies, you get a straight figure rather than a range.
About Comrie and its setting
Comrie is a village situated on the banks of the River Earn in Perth and Kinross, with a population of around 936 people. Comrie has a mix of housing types, but semi-detached homes are particularly prevalent. Comrie sits at an elevation of 61 metres, close to the nearby settlements of The Ross, Dalginross, and Polinard. Comrie is located approximately 18 miles from the city of Stirling, and 371 miles from London.
Fuel drain cover across Perth and Kinross, Comrie included
Our vans answering petrol in diesel call-outs around Comrie, in the PH postcode area, also work the places near it, The Ross, Dalginross and Polinard included. No need to bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
In Comrie and still at the petrol pump?
The best position there is, then — that is where you are. Ring, and keep it turned off.