Should You Worry? Petrol in a Diesel Car in Dales Green
Provided it hasn't been started, you can worry far less than you likely are. Till the ignition primes your pump, the starter cranks, or your vehicle is driven, petrol in a diesel tank just waits there and does no harm. Which means the honest reply to that first Dales Green question — "have I ruined it?" — usually no. To keep it that way, phone Petrol in Diesel then leave the motor switched off. The rest of this page explains what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you again.
Petrol in a diesel: what does it do to your engine?
Passing through a motor, diesel is doing two jobs at once. Before it burns, it lubricates — and then it burns. Designed to extremely fine clearances, the injectors and the pump depend on the diesel moving through them to keep their surfaces from wearing against one another.
Petrol does the first job poorly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump on the mixture wearing itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is where you get the knocking.
Put these together and the shape of the issue is clear. The damage is done by movement, not by contact. Any tank with petrol in it is a fuel fault. The beginning of a mechanical problem is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with the fuel to your injectors downstream.
Petrol in a diesel around Dales Green: how serious is it? Four cases
Filled up, and not started: nothing beats it. The petrol is in the tank and only the tank, and the task is a drain and a flush where the vehicle sits. This is the one scenario that can only really take place at a forecourt, as anywhere else your car has been driven to get there.
The ignition switched on, or a short start. With your system primed, the fuel lines and filter already contain petrol that came from the tank. Still generally easy: drain, flush, and the filter dealt with.
Those few miles driven meant your pump working on fuel diluted by petrol throughout. Tank, lines, filter, then clean fuel run through the entire system: that's this work, and the way the car was driven counts as much as the distance. Short trips, such as the school run to Castle Primary School, are one matter. A run as far as Stoke-on-Trent, under 10 miles away, is a very different job. So is any distance on the M6, under 5 miles from Dales Green, where the engine has been labouring hard throughout.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone lumpy. The motor is telling you the fuel is no longer behaving like diesel. Whether it is the verge on Dale View, a lay-by or a side street, stop where you are then leave it. A car stopped quickly very seldom has lasting damage, because the fuel drain and the flush-through, which still go first, sort it out.
Dales Green motorists and the petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Topping up removes nothing; it gives you a fuller tank of the same mixture. That advice presumes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. More precise parts and higher pressure are the way a newer diesel runs its fuel, and that makes the protection matter more, not less.
One myth that catches people out: if it starts and drives, it must be unharmed. Diesel in a petrol motor normally leaves a motor that will not run: the driver stops, and so does the harm. Feed petrol to a diesel and it usually starts, ticks over and drives away like nothing happened — all the while its pump is wearing. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the car home." It's an old workaround for a distinct issue. The petrol is still in that tank after that, and whatever it has weakened is not put back.
If your engine has been run, part of the petrol sits in the filter and the lines, not the tank — and the next start pulls it right back through the pump. So the myth "drain that tank yourself and you are sorted" doesn't stand up. It is also really dangerous to drain petrol into a can by the roadside.
Why petrol in a diesel happens at all
On purpose? Never. Through carelessness? Seldom, if ever. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle generally will not go into a petrol car at all. So the error runs one way.
It happens when routine and the vehicle stop matching. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps arranged differently. A train to catch, and a rushed fill en route to Kidsgrove. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
Preventing petrol in a diesel next time you fill up in Dales Green
- A green handle for unleaded and black for diesel is normal in the UK — but not on every forecourt. Trust the label on the petrol pump, not the colour.
- Check your filler flap. Plenty of motors state the fuel inside the flap or on the cap. Look at it on the first fill in any motor you don't know.
- A coloured fob or a sticker on your diesel's key does more than any amount of intending to remember, in a household with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. It sounds silly and it works.
- Mistakes like this are simple to make whilst your mind is on something else, so your phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to refuse a petrol nozzle, and add-on devices exist for vehicles without one. They are a backstop, not a reason to stop reading the pump.
- Spotting it mid-fill? Stop there and then. A thinner mix follows from less petrol inside your tank, but the next step stays the same: don't fire it up.
Dales Green: already put petrol in a diesel?
Then, there's only a short order of things. Do not turn the ignition on, and don't start it. The attendants on the forecourt — whether at Tesco itself or wherever you filled up — will normally help push it clear of the pump if you ask. Then ring 0333 366 0103 and tell us what was put in, about how much, and whether it's run.
If it was AdBlue rather than petrol, say so. That's a separate issue — corrosion and deposits rather than lost protection — and it has its own page for Dales Green.
Dales Green petrol in a diesel tasks: why one costs more than another
The four situations above are four different jobs, so no single price for this would be fair. What moves the cost is mostly which of them you're in. Where the car is matters too, and whether a van can safely reach it, after the share of petrol to what the tank holds.
What was put in, how much, and whether it's run — three queries we ask before quoting, not after, for precisely that reason. The answers change a range into a straight figure.
About Dales Green, for a moment
Dales Green is a locality in Staffordshire, situated inland at an elevation of 222 metres, approximately 6 miles from Stoke-on-Trent. Dales Green is characterised by its predominantly detached housing stock, reflecting its relatively rural setting. Dales Green is close to nearby places such as The Rookery, Mow Cop, and Harriseahead, and is about 141 miles northwest of London.
Dales Green and Staffordshire: where our fuel drain cover runs
Petrol in diesel call-outs in Dales Green — part of the ST postcode area — go to teams that likewise cover the locations round it, The Rookery, Mow Cop and Harriseahead among them. You need not bring your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
Dales Green: still at the pump?
In that case, you could not be in a better place. Keep it off. Call.