Gee Cross: Petrol in a Diesel Car? How Worried to Be
Not started? Then less worried than you probably feel. Everyone in Gee Cross starts with "have I ruined it?", and the honest answer is generally no: petrol resting inside your tank of any diesel remains harmless till priming, cranking or driving pulls it into the system. To keep the car that way, ring Petrol in Diesel then leave the engine switched off. Read on for three things: the effect petrol has inside a diesel motor, the clues of how far it has got, and the way to make sure you don't do it again.
What petrol in a diesel does to the engine
Passing through an engine, diesel is doing two jobs at the same time. It combusts, and before it combusts it protects. The high-pressure pump and the fuel injectors are built to extremely fine gaps, and the diesel passing through them is what keeps those surfaces from wearing against each other.
Petrol does the first job poorly and the second not at all. A pump working on a petrol mixture is wearing itself out, since petrol is thinner than diesel and takes away the protection your fuel system depends on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that is where the knocking comes.
Put these together and the shape of the problem is clear. The harm is done by circulation, not by contact. Where that petrol is only inside the tank, it's a problem of fuel, nothing more. Whatever a worn pump sheds goes on, borne by the fuel, into the fuel injectors downstream, which is why a pump that has been working on that petrol is where a mechanical fault begins.
Four situations we see in Gee Cross: how serious is petrol in a diesel?
Fuelled up, not once started. The best case there is. Only that tank has petrol in it, so the job is emptying that tank and purging your system where your car stands. This scenario can only truly take place on a forecourt: anywhere else, your car got there by being driven.
Started for a moment, or only the ignition on. Once primed, the system has pulled petrol out of your tank as far as the fuel filter and the lines. That's generally still a simple task — a drain, a flush, and your filter dealt with.
A couple of miles driven, and your pump has spent each of them running on thinned fuel. Mileage is only half of it; how hard it was driven matters just as much. Either way this work runs to that tank, the fuel lines, the filter and clean fuel through the whole circuit. A school run to Gee Cross Holy Trinity CofE Primary School is one matter. Any distance on the M67, under 3 miles from Gee Cross, means the engine working hard throughout, and a run to Manchester, under 10 miles away, makes a very different job as well.
Driven on till it complained — knocking, smoke, a lumpy idle, a soft throttle. The engine is telling you your fuel is no longer behaving like diesel. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Buckley Close. Permanent damage is very rare when a vehicle is stopped quickly, and the drain and flush-through that still come first sort it out.
Petrol in a diesel myths Gee Cross drivers hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A fuller tank of the same mix is all it gives, since topping up takes out nothing. Percentage is not how a diesel fuel system copes with petrol, however much that guidance assumes.
"Newer diesels can handle a little petrol" — a myth, and closer to the reverse. At higher pressure, through smaller components: that's how a modern diesel moves its fuel, and so the lubrication counts more, not less.
"It starts, it drives, so no harm done" — the myth that trips up most drivers than any other. Feed diesel to a petrol motor and it generally won't run, and so the driver stops — and the harm stops with them. Feed petrol to a diesel and it generally starts, idles and pulls away as if nothing has happened — all the while its pump wears. Being able to run isn't proof of being fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate problem. What petrol has weakened stays weakened, and that petrol stays in your tank regardless.
The next start sends petrol back round the pump from the fuel lines and the fuel filter, where some of it sits once the motor has run. That is why draining your tank yourself doesn't leave you sorted — a myth. And, a can of petrol drained at the kerbside is genuinely hazardous.
How does petrol in a diesel take place?
Nobody does it on purpose, and it is rarely carelessness. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol motor at all. So the error runs one way.
The moment routine stops matching the car is the moment it happens. Courtesy car, hire car, or a car that's brand new. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. A train to catch, and a hurried fill on the way to Woodley. The first fill-up in a diesel Skoda Octavia after years of driving petrol is exactly the moment it takes place. Throw in a back seat full of children, a phone call or rain, and habit takes over.
How to avoid petrol in a diesel at your next fill-up in Gee Cross
- The label is what matters, and so read the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- The first fill in a strange motor is the time to check your filler flap — inside it, or on the cap, many cars state the fuel they take.
- Good intentions count for less than a sticker or a fob in a vivid colour on your diesel's key if a house has one of each. So mark it.
- It seems silly and it works: on the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- Thinking about something else is when this becomes an easy mistake to make, so tuck the phone away then keep your mind on the pump.
- Add-on devices exist for cars without one, and some diesels come with a filler that won't take a petrol nozzle. Helpful — but a backstop only, never a reason to stop checking the label.
- Less petrol makes a weaker mix, and so stop as soon as you realise — though remembering that your next step is unchanged. It is still not to start it.
Put petrol in a diesel in Gee Cross already?
In that case, there's only a short order of things. Starting it is out, and so is turning on your ignition. Still on the forecourt, at Shell or anywhere else? Ask the attendants to help you roll the car clear of the petrol pump. Next, 0333 366 0103. We'll ask what was put in, roughly how much, and if it has been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different problem — Gee Cross has a page just for it.
Gee Cross petrol in a diesel tasks: why one costs more than another
The four scenarios above are four separate jobs, so no single quote for this would be honest. The scenario itself does most of the work of moving your cost. Next it is the proportion — how much petrol went in against how much the tank takes — and after that where the car is and whether a van can reach it safely.
What got in, how much, and if it has run — three questions our engineers ask before costing, not after, for precisely that reason. A range becomes a straight figure when those replies are in.
About Gee Cross and where it is
Gee Cross is a suburban area in Greater Manchester, situated approximately 7.8 miles east of Manchester city centre. Gee Cross sits at an elevation of around 165 metres, near the rural landscapes of Werneth Low and Woodley. Gee Cross has a population of around 5077 people, predominantly living in semi-detached housing. Gee Cross is also close to nearby neighbourhoods such as Backbower.
Gee Cross and Greater Manchester: where our fuel drain cover reaches
The vans answering petrol in diesel jobs in Gee Cross, in the SK postcode area, equally work the spots near it, Backbower, Werneth Low and Woodley among them. Our engineers drain where your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the petrol pump in Gee Cross?
The best position there is, then — that is where you are. Phone, and leave it switched off.