How Worried Should You Be? Petrol in a Diesel Car in Wistaston
Provided it hasn't been started, you can worry less than you likely are. Everyone in Wistaston begins with "have I ruined it?", and the honest answer is usually no: petrol left in your tank of any diesel stays harmless until priming, cranking or driving pulls it into the fuel system. To leave the vehicle like that, ring Petrol in Diesel and leave your motor switched off. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and ways to make sure you never repeat it.
Petrol in a diesel: what does it do to the motor?
On its way through an engine, diesel does two jobs. Before it combusts, it lubricates — then it combusts. Built to very fine tolerances, the injectors and the pump rely on your diesel moving through them to stop their surfaces wearing against one another.
The second job petrol doesn't do at all, and the first it does badly. It's thinner than diesel and removes the protection the system depends on, so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the knocking comes from.
The shape of the problem is clear when you put those together. The harm is done by movement, not by contact. A tank with petrol in it is a fuel fault. Whatever a worn pump sheds travels on, carried by the fuel, into the fuel injectors downstream, which is why a pump that has been working on that petrol is where a mechanical issue begins.
Wistaston, petrol in a diesel: four cases, from mild to serious
The best case there is: filled up, never started. Just your tank has petrol in it, so the job is draining the tank and purging the system where your car sits. This situation can only truly occur on a forecourt: anywhere else, your car got there by being driven.
Ignition on, or started for a moment. Once primed, the fuel system has drawn petrol from that tank up to the fuel filter and the lines. That is generally still a simple job — a drain, a flush, and the fuel filter dealt with.
Some miles driven, and the pump has spent every one of them running on diluted fuel. How hard your car was driven counts as much as how far, and the work takes in your tank, your lines, the filter and fresh fuel through the entire system. On the school run to Wistaston Church Lane Academy, the mileage is small. Very different a second time: a run to Stoke-on-Trent, under 15 miles away, or some mileage on the M6, under 10 miles from Wistaston, where the engine never stopped running hard.
Driven till it complained. Rattling, a lumpy idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer behaving like diesel. Leave it where it stops: a lay-by, a quiet street, the verge on Windsor Road. Long-term damage is very uncommon if a car is stopped early, and the fuel drain and flush that still go first sort it out.
Petrol in a diesel myths Wistaston people hear
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed when you top up — your tank simply carries more of the same mixture. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance presumes.
Myth: a newer diesel copes with a bit of petrol. If anything, the reverse. At higher pressure, through more precise components: that's how a modern diesel handles its fuel, so the lubrication counts more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools drivers. Any petrol motor fed diesel generally won't run, and so the motorist stops and the damage stops with them. A diesel fed petrol generally starts, ticks over and drives away as if nothing has happened, whilst the pump wears. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the car home." It's an outdated fix for a different fault. None of what petrol thinned is put back by it — and afterwards, the tank still contains that petrol.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol sits in your filter and lines, waiting to go right back through the pump on the next start. Also, a can of petrol drained by the roadside is genuinely risky.
Why petrol in a diesel occurs at all
A careless moment is seldom the cause, and nobody means to do it. A diesel nozzle generally will not go into a petrol car, but the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error easy, and just in one direction.
The moment routine stops matching your car is the moment it happens. Courtesy car, hire car, or a car that's new. One petrol and one diesel on the driveway of the same household. The pumps in a different order on a familiar forecourt. A train to catch, and a rushed fill on the way to Crewe. Precisely the moment it occurs: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
Preventing petrol in a diesel next time you fill up around Wistaston
- The label is what counts, and so read the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- Plenty of cars state the fuel type inside the filler flap or on the cap, so check there on your first fill in a car you don't know.
- Mark the 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 intending to remember.
- Before the nozzle leaves the pump the first time you fill a hired or new motor, say "diesel" out loud. Daft, yes, but it does the trick.
- Put the phone away. This is an easy mistake to make whilst you are thinking about something else.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the petrol pump.
- Less petrol means a thinner mix, so stop the moment you realise — though remembering that the next step is unchanged. It is still not to fire it up.
Wistaston: already put petrol in a diesel?
The order of things is brief, then. Don't start it, and don't switch your ignition on. Yet on the forecourt, at BP or anywhere else? Ask the attendants to help you push the car clear of the pump. Then ring 0333 366 0103 and tell us what went in, roughly how much, and if it's run.
Corrosion and deposits are the trouble with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and see its own Wistaston page.
One petrol in a diesel task in Wistaston costs more than another. Why?
The four scenarios above are four different tasks, so no single quote for this would be fair. Mostly, your cost shifts with which situation you're in. The proportion counts next, meaning how much of your tank is petrol, followed by the position of the car and whether reaching it is safe for a technician.
Three queries come first, before quoting, rather than after — what was put in, how much, has it run — and this is the reason. Given those answers, there is a straight figure instead of a range.
About Wistaston
Wistaston is a suburban area in Cheshire, situated near the River Dane and characterised by its predominantly detached housing stock. Wistaston sits at an elevation of 49 metres, with nearby places including Wells Green, Willaston, and Wistaston Green. Wistaston is located approximately 13 miles from Stoke-on-Trent and 147 miles from London, making it a commuter-friendly location. Wistaston has a population of around 2875 residents.
Fuel drain cover across Cheshire, Wistaston included
Our teams answering petrol in diesel call-outs in Wistaston, in the CW postcode area, also work the spots around it, Wells Green, Willaston and Wistaston Green included. Our engineers drain where the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the pump in Wistaston, still?
The best place there is, then — that's where you are. Phone, and leave it switched off.