Petrol in a Diesel Car in Portlethen: How Worried Should You Be?
Likely less than you are now — provided no one has started the car. Petrol sitting in a diesel tank does nothing to your motor till something pulls it through the fuel system — the ignition priming the pump, your starter, or driving on its own. So the fair answer to the first question everyone in Portlethen asks, "have I ruined it?", is normally no. To leave it that way, phone Petrol in Diesel and leave the motor alone. What petrol actually does to a diesel, how to judge how far it has travelled, and how to keep it from happening a second time: that's the remainder of this page.
Inside the engine: what petrol in a diesel really does
On its way through an engine, diesel has two tasks. It lubricates first, and after that does it burn. What stops the surfaces inside the high-pressure fuel pump and the fuel injectors from wearing down against each other is the diesel flowing through them — they're built to very fine tolerances.
Of those two jobs, petrol manages the first poorly and the second never. It's runnier than diesel and takes away the lubrication your 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 clattering comes from.
The shape of the problem is plain when you put those together. It is movement that does the damage, not contact. Where the petrol is only in that tank, it is a fault of fuel, nothing more. A pump that has been labouring on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with your fuel to your injectors downstream.
Four situations we see in Portlethen: how bad is petrol in a diesel?
Fuelled, and not started: nothing beats it. Being on a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol held in the tank alone, it is drained and rinsed on the spot, and nothing more is needed.
Started for a second, or just your ignition on. Petrol has come out of that tank and got to the filter and the fuel lines, since your system has been bled. Usually nothing more than clearing, cleaning and sorting the filter, and so still simple.
Driven a few miles. Now your pump has spent those miles running on thinned fuel. The work is that tank, your lines, your filter and fresh fuel through the whole circuit, and how hard the vehicle was driven counts as much as how far. On the school run to the local primary school, the distance is small. A run as far as Aberdeen, under 10 miles away, is a very different job. So is any distance on the M90, over 50 miles from Portlethen, where your engine has been running hard the whole time.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone lumpy. That is your engine telling you its fuel no longer is acting like diesel. Whether it's the verge on Cookston Road, a lay-by or a side road, stop there then leave it. The fuel drain and flush-through still come first, and they take care of it: if a car is pulled over soon, permanent damage is very rare.
Petrol in a diesel stories Portlethen motorists hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mix. The idea behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Current diesels can handle a little petrol" — a myth, and closer to the reverse. Finer components and higher pressure are how a modern diesel runs its fuel, and that makes the lubrication matter more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there's no harm done." A petrol engine fed diesel normally will not run, and so the driver stops and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump grinds. Running isn't the same as fine.
An old workaround for a distinct issue is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." The petrol is still inside your tank after that, and what it has thinned isn't put back.
"Drain it yourself and you are sorted" — a myth, since after it has been running some petrol lies in the fuel filter and lines, ready to go straight back through your pump on your next start. Draining petrol into a can at the roadside is also truly hazardous.
Petrol in a diesel: how does it occur?
No one does it on purpose, and it's seldom carelessness. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol vehicle at all. The forecourt makes it easy, and the slip runs one way.
When routine and the car stop matching, it happens. Hire cars, courtesy cars, and vehicles that are new to you. Two cars on one driveway, one petrol, one diesel. A forecourt you know, but with its pumps arranged differently. A train to catch, and a rushed fill en route to the nearest station. Precisely the moment it occurs: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. With rain, a call arriving, or children to deal with, your hand just does what it has always done.
How to avoid petrol in a diesel on your next fill-up around Portlethen
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Read the pump's label; the colour is just a clue.
- The first fill in a strange vehicle is the time to check the filler flap — on it, or on the cap, plenty of cars state which fuel to use.
- Label your key. In a home with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. It seems silly and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away then keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to reject a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop checking the petrol pump.
- The moment you notice, stop: less petrol in that tank means a weaker mixture. What to do next does not change, though — still do not fire it up.
Put petrol in a diesel around Portlethen already?
Then, there's only a short order of things. Never fire it up, and don't turn the ignition on. If you are still at the forecourt — Asda or anywhere else — ask the attendants to help you push the car away from the pump. Ring 0333 366 0103 next, with three facts — your fuel, the approximate quantity, and whether it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate fault — Portlethen has a page just for it.
One petrol in a diesel task around Portlethen costs more than another. Why?
The four situations above are four different tasks, so no single quote for this would be fair. What moves the cost is mostly which of them you're in. After that it's the ratio — how much petrol went in against how much that tank takes — and after that where your car is and whether a van can reach it safely.
What was put in, how much, and if it has run — three questions our engineers ask before costing, not after, for exactly that reason. A range becomes a straight figure once the replies are in.
About Portlethen, briefly
Portlethen is a coastal town in Aberdeenshire, situated approximately 6 miles south of Aberdeen. Portlethen sits at an elevation of around 71 metres, overlooking the North Sea. Portlethen has a mix of residential areas, including the older Portlethen Village and more modern developments, with detached housing being predominant. Portlethen is close to nearby places such as Hillside and Findon, and is around 392 miles from London.
Fuel drain cover across Aberdeenshire, Portlethen included
Our teams answering petrol in diesel call-outs in Portlethen, in the AB postcode area, equally work the spots around it, Hillside, Portlethen Village and Findon among them. No need to move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places where we work.
Still at the pump around Portlethen?
Then, you could not be in a better position. Keep the car turned off, and ring.