Petrol in a Diesel Car in Coed Mawr: How Worried Should You Be?
Unstarted? Then less worried than you likely are. Petrol sitting in a diesel tank does nothing to the engine until something pulls it through the system — your ignition priming your pump, the starter, or driving on its own. So the honest answer to the first question everyone in Coed Mawr asks, "have I ruined it?", is normally no. Keep it that way: leave the motor off and phone Petrol in Diesel. Keep reading 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 don't repeat it.
Your engine and petrol in a diesel: what happens
Passing through a motor, diesel does two things at once. Before it ignites, it lubricates — and then it ignites. Made to extremely fine gaps, the fuel injectors and your pump depend on the diesel moving through them to keep their surfaces from wearing against one another.
Petrol handles the first job badly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump running on the blend to wear itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the clattering.
Put those together and the shape of the problem is clear. Not contact but circulation is what does the harm. Petrol in a tank is a fuel issue. Whatever a worn pump sheds travels on, borne by the fuel, into the injectors downstream, which is why a pump that has been working on the petrol is where a mechanical problem begins.
Coed Mawr, petrol in a diesel: four situations, from mild to major
The best case there is: filled up, not once started. Only your tank has petrol in it, and so the task is emptying your tank and purging your system where your car sits. This scenario can only really take place at a forecourt: anywhere else, the car got there by being driven.
Started for a moment, or just the ignition on. Once primed, the system has drawn petrol out of that tank up to the filter and your lines. That is generally still an easy job — a drain, a flush, and the fuel filter dealt with.
The pump now spent a couple of miles on diluted fuel — that's what driving the car does. Distance is only half of it; how hard it was driven matters just as much. Either way the work includes your tank, the fuel lines, your filter and clean fuel through the whole circuit. Short trips, such as the school run to the local primary school, are one matter. A run as far as Bangor, under 3 miles away, is a very different job. So is any distance on the Moreton Spur, under 50 miles from Coed Mawr, where your engine has been labouring hard the whole time.
Driven till it complained. Clattering, a ragged idle, smoke, a throttle that has gone soft. The motor is telling you the fuel is no longer behaving like diesel. Pull up where you are — on the verge on Ffordd Coed Mawr, at the kerb, down a side road — and don't move it. What goes first is still the fuel drain and flush-through, and that deals with it, with long-term damage very uncommon if a car is pulled over early.
Myths Coed Mawr motorists hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up takes out nothing; it gives you a fuller tank of the same mixture. That advice supposes a diesel fuel system tolerates petrol by percentage. It does not.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. Protection counts more on modern diesels, not less, because their fuel runs through more precise components at higher pressure.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol motor and it usually will not run, so the motorist stops — and the damage stops with them. Whilst the pump wears, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. Being able to run is not proof of being fine.
An old fix for a distinct problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." It doesn't put back what petrol has thinned, and that petrol is still in the tank later on.
Once the motor has been run, part of that petrol sits in the fuel filter and the lines, not your tank — and the next start pulls it straight back through the pump. So the myth "drain your tank yourself and you are sorted" doesn't hold. Also, a can of petrol drained at the kerbside is genuinely risky.
How does petrol in a diesel occur?
No one does it on purpose, and it is seldom carelessness. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol motor at all. The forecourt makes it simple, and the error runs one way.
When habit and the car stop matching, it takes place. Courtesy car, hire car, or a motor that's new. One petrol and one diesel on the drive of the same household. Your usual forecourt, its pumps now in a different order. A train to catch, and a rushed fill on the way to Bangor (Gwynedd). Years of petrol cars behind you, a diesel Volkswagen Passat in front of you on the forecourt for its first tank — that is when. The hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
Next time you fill up around Coed Mawr: preventing petrol in a diesel
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most usually do. Read the petrol pump's label; the colour is only a hint.
- Many motors state the fuel inside the filler flap or on the cap, and so check it on the first fill in any car you don't know.
- One of each in the house? Mark your key to your diesel — a coloured fob, a sticker — since meaning to remember isn't enough.
- "Diesel", out loud, before you lift the nozzle — every time a new or hired car gets its first tank. It seems daft. It works.
- Whilst you're thinking about something else, this is an easy mistake to make — so put your phone away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to block a petrol nozzle, and add-on devices exist for the rest. Count it as a backstop, and keep checking the pump.
- Stop as soon as you realise. Less petrol inside your tank makes a thinner blend. It does not change what to do next, which is still not to fire it up.
Put petrol in a diesel around Coed Mawr already?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition switched off as well. Ask the staff to help you push it clear of the petrol pump if you are still at the forecourt, whether that is Texaco or anywhere else. What went in, about how much, and whether it has run: tell us that when you phone 0333 366 0103.
If it was AdBlue instead of petrol, say so. That's a separate fault — corrosion and deposits rather than lost lubrication — and it has its own page for Coed Mawr.
What makes one Coed Mawr petrol in a diesel task cost more than the next
Four different jobs sit behind the four situations above — which is why there's no honest single price. Which of them you are in is mostly what moves the cost. Beyond that it is the share — how much petrol was put in against how much that tank holds — and after that where the vehicle is and whether a technician can reach it safely.
What was put in, how much, and if it's run — three queries our technicians ask before pricing, not after, for exactly that reason. Their answers are what turn a range into one firm number.
About Coed Mawr, for a moment
Coed Mawr is a suburban area situated on the coast of northwest Wales, near the city of Bangor. Coed Mawr lies at an elevation of 48 metres, with views out to the surrounding coastline and the Menai Strait. Coed Mawr is characterised by its predominantly semi-detached housing stock, with nearby neighbourhoods including Bryn-Llwyd and Glan-Adda.
Fuel drain cover in Coed Mawr and across Gwynedd
Coed Mawr sits in the LL postcode area, and our teams that answer petrol in diesel call-outs there work the places around it as well — Bryn-Llwyd, Glan-Adda and West End among them. The car does not need to come to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the pump around Coed Mawr, still?
The best place there is, then — that is where you are. Keep it off. Ring.