How Worried Should You Be? Petrol in a Diesel Car in Cefn-coed-y-cymmer
Likely less than you already are — provided nobody has started the vehicle. Everyone around Cefn-coed-y-cymmer begins with "have I wrecked it?", and the fair answer is generally no: petrol resting in your tank of a diesel remains harmless till priming, cranking or driving draws it into the fuel system. Petrol in Diesel is who to call, with your motor left off, so it stays that way. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to keep it from happening a second time: that is the remainder of this page.
Inside the motor: what petrol in a diesel really does
Two tasks fall to diesel on its journey through a motor. It lubricates to begin with, and after that does it burn. The high-pressure fuel pump and the fuel injectors are built to extremely fine tolerances, and the diesel passing through them is what stops those surfaces from wearing down against one another.
Of these two jobs, petrol handles the first badly and the second never. A pump working on a petrol mixture is wearing itself out, since petrol is thinner than diesel and strips out the lubrication the fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that is where any knocking comes.
Combined, those make the shape of the issue clear. Not contact but circulation is what does the harm. All a tank with petrol in it amounts to is a fuel fault. The beginning of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to your injectors downstream.
Four situations our engineers see around Cefn-coed-y-cymmer: how serious is petrol in a diesel?
Fuelled, and not started: nothing beats it. Just that tank has petrol in it, and so the job is draining the tank and cleaning the fuel system where the vehicle sits. This scenario can only truly happen on a forecourt: anywhere else, the vehicle got there by being driven.
A brief spell of running, or merely the ignition on. Petrol has come out of that tank and reached the fuel filter and the lines, because your system has been bled. That's normally still an easy job — a drain, a flush, and the fuel filter seen to.
The pump has spent a few miles on diluted fuel — that's what driving it meant. How hard the vehicle was driven matters as much as how far, and this work covers the tank, your lines, the filter and fresh fuel through the entire system. A school run to the local primary school is one thing. Any miles on the M4, under 25 miles from Cefn-coed-y-cymmer, means your engine has worked hard throughout, and a run to Newport, under 25 miles away, makes a very different task too.
Driven until it complained. Knocking, a lumpy idle, smoke, a throttle that has gone soft. That is your motor telling you its fuel no longer is acting like diesel. Stop where you are — on the verge on Old Chapel Road, at the kerb, down a side road — and do not move it. The fuel drain and flush still go first, and they sort it out: when a vehicle is stopped early, lasting damage is very uncommon.
Cefn-coed-y-cymmer people and the petrol in a diesel stories they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." A bigger tank of the same mix is all you get, because topping up removes nothing. The assumption behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A current diesel can cope with a bit of petrol." A current diesel sends its fuel through more precise components at higher pressure, which makes the protection count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that catches people. Diesel in a petrol motor normally means a motor that won't run: the motorist stops, and so does the damage. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, while your pump wears. Running isn't the same as fine.
An outdated fix for a different issue is behind this one. Myth: "Add some two-stroke oil and drive the car home." That petrol is still inside that tank after that, and whatever it has thinned is not put back.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol sits in the fuel filter and lines, ready to go right back through your pump at the next start. It is also really hazardous to drain petrol into a can by the kerbside.
Petrol in a diesel: how does it occur?
No one does it on purpose, and it's seldom carelessness. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle mostly will not go into a petrol car at all. So the slip runs one way.
Routine and the vehicle falling out of step is how it occurs. Any car that is new to you — a hire car, on loan as a courtesy car, or just bought. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps arranged differently. Rushing for a train at Merthyr Tydfil and filling up en route. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Volkswagen Passat for the first time. Throw in a back seat full of kids, a phone call or rain, and the hand takes over.
Cefn-coed-y-cymmer motorists: how to prevent petrol in a diesel next time
- A green handle for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Trust the label on the pump, not the colour.
- Many vehicles state the fuel type inside your filler flap or on the cap, so check it on your first fill in a vehicle you don't know.
- Label the key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car needs its first tank. It seems silly. It works.
- Put your phone away. This is an easy mistake to make while you are thinking about something else.
- Some diesels come with a filler built to refuse a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- As soon as you realise, stop: less petrol inside the tank means a weaker blend. What to do next doesn't change, though — still do not fire it up.
Already put petrol in a diesel in Cefn-coed-y-cymmer?
Then, there is only a short order of things. Starting it is out, and so is turning on the ignition. Ask the attendants to help you roll it away from the petrol pump if you're still at the forecourt, whether that's Applegreen or somewhere else. Then ring 0333 366 0103 and tell us what was put in, about how much, and whether it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a different problem — Cefn-coed-y-cymmer has a page just for it.
One petrol in a diesel task around Cefn-coed-y-cymmer costs more than another. Why?
A fair single quote doesn't exist here: four situations, four separate tasks. Which of them you're in is chiefly what moves your cost. Two things follow that: the petrol that got in as a share of what that tank takes, then the spot the vehicle is in and whether a technician can get to it safely.
Three queries come first, before any quote, rather than after — what got in, how much, has it run — and this is the reason. Given the replies, there is a straight figure instead of a range.
About Cefn-coed-y-cymmer, briefly
Cefn-coed-y-cymmer is a suburban area in Merthyr Tydfil, situated on the riverside at an elevation of 217 metres. Cefn-coed-y-cymmer has a mix of housing types, but is predominantly characterised by terraced homes. Cefn-coed-y-cymmer is located near other local places such as Gellideg and Clwydyfagwyr, and is within commuting distance of Newport. Cefn-coed-y-cymmer is home to a population of around 2800 people.
Fuel drain cover in Cefn-coed-y-cymmer and across Merthyr Tydfil
Cefn-coed-y-cymmer waits in the CF postcode area, and the teams that answer petrol in diesel call-outs there work the spots around it as well — Gellideg, Clwydyfagwyr and Trefechan among them. No need to move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places where we work.
Still at the pump around Cefn-coed-y-cymmer?
No position is better: that is where you are. Phone, and leave it switched off.