Petrol in a Diesel Car in Mochdre: How Worried Should You Be?
Likely less than you are now — as long as nobody has started it. Petrol sitting in a diesel tank does nothing to your motor till something pulls it through your fuel system — your ignition priming your pump, your starter, or the drive itself. So the honest answer to the first query everyone around Mochdre asks, "have I wrecked it?", is usually no. Keep it like that: leave your engine off and call Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and the way to make sure you don't do it again.
Inside your engine: what petrol in a diesel really does
Two tasks fall to diesel on its journey through a motor. Before it ignites, it protects — and then it combusts. Very fine clearances are built into your injectors and your high-pressure pump, and just your diesel flowing through stops those surfaces grinding together.
Poorly at the first, not at all at the second: that's petrol. The clattering comes from petrol being made 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 out the protection the fuel system depends on, and any pump working on that mixture is wearing itself.
The shape of the problem is plain when you put those together. Not contact but movement is what does the harm. All a tank with petrol in it amounts to is a fuel problem. The start of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors beyond it.
Four scenarios our technicians see around Mochdre: how bad is petrol in a diesel?
The best case there is: filled up, not once started. The petrol is inside that tank and only your tank, and the job is a drain and a flush where the vehicle stands. This is the one scenario that can only really take place on a forecourt, because anywhere else your car has been driven to get there.
Ignition on, or started for a moment. With your system primed, your lines and filter now hold petrol that has come from your tank. That is usually still an easy job — a drain, a flush, and the fuel filter dealt with.
Your pump has worked a few miles on thinned fuel — that is what driving it meant. Distance is only half of it; how hard it was driven matters just as much. Either way the work runs to the tank, your lines, your filter and fresh fuel through the whole system. A school run to the local primary school is one thing. Very different a second time: a run to St Asaph, under 15 miles away, or any mileage on the Moreton Spur, under 50 miles from Mochdre, where your engine never stopped labouring hard.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven till it complained. The fuel is not acting like diesel any more, and your engine is telling you. Stop on the spot — on the verge on Conway Road, at the kerb, down a side road — and do not move it again. Lasting damage is very rare if a car is stopped soon, and the fuel drain and flush that still come first take care of it.
Petrol in a diesel stories Mochdre motorists hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Topping up takes out nothing; it gives you a fuller tank of the same mixture. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance assumes.
Not so: a modern diesel copes with a bit of petrol. If anything, the reverse. A current diesel runs its fuel through more precise components at higher pressure, which makes the lubrication matter more, not less.
The myth that catches drivers out: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it usually won't run, and so the driver stops — and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile your pump grinds. Fine and running are not the same at all.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate fault. It doesn't put back what petrol has diluted, and the petrol is still inside the tank later on.
Myth: "Drain your tank yourself and you're sorted." Once the motor has been run, some of that petrol is no longer in your tank: it is in your filter and your lines, and it goes right back through your pump at the next start. It's also genuinely hazardous to drain petrol into a can by the roadside.
How does petrol in a diesel occur?
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle generally will not go into a petrol car, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error simple, and just in one direction.
Routine and the car falling out of step is how it takes place. Hire cars, courtesy cars, and vehicles that are new to you. One petrol and one diesel on the drive of the same household. A well-known forecourt with the pumps in a different order. Rushing for a train at Colwyn Bay and fuelling up en route. A new-to-you diesel Renault Megane, its first fuelling, and a motorist used to petrol: precisely when it takes place. With rain, a call coming in, or a car full of children to deal with, the hand just does what it always has.
Mochdre people: how to prevent petrol in a diesel next time
- Read the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on each forecourt. The label is what counts.
- Plenty of cars state the fuel inside the filler flap or on the cap, and so check there on the first fill in any motor you don't know.
- 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 meaning to remember.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car gets its first tank. It sounds silly. It does the trick.
- Mistakes like this are easy to make whilst your mind is on something else, and so your phone goes away.
- Add-on devices are available for motors without one, and some diesels are built with a filler that won't accept a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label.
- Noticing it mid-fill? Stop there and then. A weaker blend results from less petrol in your tank, but the next stage remains the same: don't fire it up.
Petrol already in a diesel in Mochdre? Start here
Then, there's just a short order of things. Leave it unstarted, with the ignition switched off too. If you're still on the forecourt — Texaco or anywhere else — ask the attendants to help you roll the vehicle clear of the pump. Next, 0333 366 0103. We will ask what got in, about how much, and if it has been run.
Corrosion and deposits form the trouble with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and see its own Mochdre page.
Why one petrol in a diesel job around Mochdre costs more than another
Four different tasks lie behind the four scenarios above — which is why there is no honest single price. What shifts your cost is chiefly which of them you're in. Two things come after that: the petrol that was put in as a share of what your tank holds, then the spot your car is in and whether a van can reach it safely.
Ahead of any quote, not after, we ask three queries: the fuel that went in, its volume, and whether it's run. That is why. Those answers are what turn a range into one firm number.
About Mochdre, for a moment
Mochdre is a suburban area in Conwy, Wales, situated near the coast at an elevation of 13 metres. Mochdre lies close to several nearby places, including Bron-y-Nant, Dolwyd, and Llangwstenin, and is approximately 13 miles from the city of St Asaph. Mochdre has a population of around 2005 people, predominantly living in semi-detached housing. Mochdre is located near the north Welsh coast, within commuting distance of larger towns and cities.
Mochdre and Conwy: where our fuel drain cover runs
Bron-y-Nant, Dolwyd and Llangwstenin are among the places around Mochdre that the same vans work, answering petrol in diesel calls across Mochdre's LL postcode area. Our engineers drain where the car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the petrol pump around Mochdre, right now?
Then, you could not be in a better position. Turned off it remains; then call.